Faculty of Applied Sciences

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Adressing food and nutrition insecurity through the development and implementation of an agricultural and nutrition education programme on legumes for older farmers living in Mariannhill, KwaZulu-Natal, South Africa
(2020) Mkhize, Nkumbulo Xolile; Napier, Carin E.; Oldewage-Theron, Wilna; Duffy, Kevin Jan
Introduction Food and nutrition security can be influenced by various external and internal factors that contribute to a compromised wellbeing status amongst older farmers who are considered as a vulnerable group. This group faces diverse socio-economic and health challenges within an evolving food system. The complexity of this challenge persistently requires multisectoral intervention programmes, as reflected in the nature of this study. Aim and Objectives The aim of the study was to determine the levels of and address the food intake and nutrition insecurity status of elderly farmers. The main objective was to address the challenges that compromised the health of selected previously non-legume producing farmers by encouraging legume production and consumption amongst them. The findings of the study informed the proposal of appropriate strategies to develop an intervention programme intended to educate the identified elderly farmers and to promote their dietary diversification by means of legume production and consumption. Methodology The study employed a cross-sectional design. A baseline study was conducted that aimed at examining variable relationships using a mixed methods approach involving both qualitative and quantitative data collection techniques. A sample of 112 elderly farmers participated in the baseline study, followed by a case-controlled intervention programme that included preand post-intervention surveys. The measuring instruments included socio-demographic as well as health and medical surveys to elicit data such as blood pressure, blood indices for glucose and cholesterol due to dietary intake, household food security, legume knowledge, legume acceptability and agricultural practices. The data informed the findings of both the baseline and the intervention phases of the study. The baseline study involved a sample of 112 elderly farmers, whereas the intervention study involved two case controls (n=103) that comprised an experimental group (EG: n=53) and a control group (CG: n=50). Data were obtained for both groups by analysing blood indices, dietary intake, yields of legume production (EG only) and legume acceptability levels using statistical analyses of variance, significance and trends of pre- and post-intervention surveys over two years. A follow-up survey (FU) was conducted six months after the conclusion of the intervention phase and involved only the EG (n=32), to assess the impact of the intervention programme on their dietary intake and farming practices. The follow-up study thus compared the intervention data of the farmers’ consumption and production patterns with data obtained postintervention. During this latter study, only dietary intake and production levels were measured. All the data were analysed using IBM Statistical Package for Social Sciences (SPSS), Food Finder software, the Mann-Whitney U test, Analysis of Variance (ANOVA) and T-tests for statistical frequencies, variances and correlations. Results In the baseline study, 79.5% of the participants were women. The mean age of the participants was 63.3 ± 8.2 years. A diverse legume consumption was not observed as indicated by a low legume food group diversity score (FGDS) for 0-9 varieties with a mean of 3.5 (SD ± 1.70). Legumes were the least (19.0%) preferred crop planted by the farmers prior to the study. In the intervention study, the majority of participants were also women (73.6% in the EG and 66.0% in the CG). Of the six varieties of legumes under study, red kidney beans was the most preferred (141.60 kg/ha-1 SD ± 162.11). There was a high significance (p=0.001) amongst the six legume varieties produced, which implies that some legumes had a higher yield than others. A comparison between the genders indicated that the women produced 81.70 kg/ha-1 (SD ± 77.95), while the men produced 33.63 kg/ha-1 (SD ± 166.40). The higher yields produced by the women were significant (p=0.011). Legume consumption improved for the EG because the intervention programme resulted in a significantly (p=0.000) increased dietary diversity score (DDS) of legume intake with a mean (±SD) FGDS from 2.4 (SD ± 1.35) to 5.7 (SD ± 2.56) and a mean (±SD) Dietary Diversity Score (DDS) from 8.59 ± 0.74 to 8.23 ± 1.11, while that of the CG was 3.0 (SD ± 1.82). According to the post-intervention survey, the blood results of the EG indicated nutrient improvement at the 5.0% significance level for blood glucose (p=0.038) and cholesterol (p=0.008). The blood glucose levels of the EG were statistically significant (p=0.037) when this group was compared with the CG in both the pre-intervention and post-intervention surveys. Trend analyses were conducted and compared between those men and women who participated throughout the study (i.e. participation from the baseline to the post-intervention surveys). It was found that cholesterol (p=0.033) and Systolic Blood Pressure (SBP) (p=0.013) were statistically significant when the genders were compared across all phases of the study. Data obtained for the EG in the Follow Up (FU) study six months after the intervention study indicated that the production of legumes had declined (71.8%). This was because the legume intake with a mean (±SD) FGDS of 3.0 ± 2.2 indicated a significant (p=0.000) drop from 5.7 (SD ± 2.56) with DDS from 8.23 (± 1.11) to 8.81 (± 0.47) at p=0.005 significance as determined by the FU survey. It was also found that limited marketing of legumes had occurred, which suggests that the sustainability of legume production and consumption post-intervention by the elderly farmers was a challenge. However, 100.0% of the farmers indicated that they intended to continue their production and consumption of legumes, provided that the constant supply of legumes did not cease. Conclusions Evidence was obtained that the intervention project positively impacted the production and consumption of legumes and that the elderly farmers thus diversified their dietary intake for the better during this phase of the study. However, further investigations need to be conducted to explain the decline in consumption and production in the post-intervention period if support for a healthier lifestyle amongst elderly farmers is to be sustained. The technology to produce legumes with high yields to address food insecurity through more appropriate consumption patterns also needs to be explored in greater depth. Because the two streams of knowledge transfer that involved hands-on training of elderly farmers improved legume production and consumption patterns, this study established a sound foundation on which future studies and intervention strategies for food security amongst vulnerable groups may be built.
Analysis of the nutritional status and dietary intake data of a group of elderly at a day and frail care centre in Verulam
(2011) Govender, Theloshni; Oldewage-Theron, Wilna; Napier, Carin E.
Background: South Africa, a richly diverse developing country has been faced by the consequences of transition attributed to urbanisation and acculturation. A Westernised lifestyle has, therefore, resulted in increasing disease patterns that are characterized by a combination of poverty-related diseases together with the emerging chronic diseases. The shift to a Westernised lifestyle has resulted to a shift in the composition of dietary staples leading to dietary factors related to an increase in lifestyle diseases. These include a high fat, low fibre diet, as well as an inadequate intake of fruits and vegetables. However, this in turn has led to higher energy intakes with insufficient and imbalanced micronutrient intake. Research conducted amongst the elderly in South Africa has clearly indicated that the elderly live within a limited financial budget leading to extreme levels of food insecurity and the social burden of being the head of the household, in addition to being the caregiver to grandchildren and sick children. Due to the current living status the elderly encounter reduced food intake in addition to a reduced variety in their diet, therefore, micronutrient deficiencies are common amongst this age group. Therefore, a consumption of energy-dense foods, particularly staple foods, to stretch the food budget which are more affordable and thus allow for an increased consumption is evident. Aim: To determine the socio-demographic profile, health and nutritional status in relation to the dietary intake patterns to reflect malnutrition among free living elderly (60yrs+) in Verulam. Methodology: Fifty nine randomly selected men and 191 women aged 60+ participated on a voluntary basis in this study. A descriptive survey method was used for this cross sectional study. Trained fieldworkers assisted with the administration of all questionnaires and a registered nurse measured blood pressure. Socio-demographic questionnaires were administered to determine the socio-economic characteristics of the elderly within this community. Anthropometric measurements determined the Body Mass Index according to the World Health Organisation and Asian cut-off points to indentify the risk factors. The Health questionnaire identified the health status correlated to the respondent’s profundity of disease and deficiencies associated to dietary patterns. Blood pressure measurements were taken to determine the hypertension prevalence related to the dietary intake. Two 24-Hour Recall questionnaires were completed by the 250 respondents to identify actual vii food intake and measured against the Dietary Recommended Intake (DRIs). A food frequency questionnaire (FFQ) determined the respondent’s food variety score over a period of one week. The socio-demographic questionnaire, health questionnaire, food frequency questionnaire and anthropometric measurements were captured on an Excel® spread sheet by the researcher and analyzed for descriptive statistics using the Statistical Package for the Social Sciences (SPSS) version 17.0 with the assistance of a statistician. The 24-Hour Recall data were captured and analyzed by a nutrition professional using the MRC Food Finder® version 3.0 software, based on the South African Food Composition tables. Results: The majority of the respondent’s role in the family was mothers (70.8%) and lived in an urban area (68.8%). In addition, 73.2 percent (n=183) of the respondents shared the house with one to five people, and lived in a brick house (74.4%, n=186) with more than 3 rooms (74.0%, n=185). The elderly in this sample were pensioners and, therefore, 76.0 percent (n=190) received state grants of which the total household income ranged between R1001-R1500 (35.2%, n=88). Food insecurity is prevalent as reported by 28.4 percent. Primary school was the highest level of education completed by 52.4 percent (n=131) and English is the most spoken language amongst this group (74.0%, n=185). Women had higher BMI values particularly in the overweight (18.32%, n=35) and obese I and II (58.6%, n=112) categories when compared with men. Blood pressure measurements indicated that 60.0 percent (n=150) of the respondents suffered from hypertension. The use of chronic medication was reported by 84.4 percent (n=212). The total range of individual food items consumed by an individual during the seven-day data collection period measured by the (FFQ) was between 4-66 foods. However, the highest consumption was four food items by 23.2 percent (n=58) of the respondents. The summary of the food variety within food groups indicated a high dietary diversity, of which the other vegetable group reported the highest individual mean FVS (±SD) of 10.86 (±5.82), followed by other fruit, cereal, flesh and Vitamin A rich groups with 5.73 (±4.41), 5.03 (±1.85), 4.08 (±2.23) and 2.43 (±1.09) respectively. The nutrient analysis indicated a deficient intake by both men and women of all the nutrients, except for the mean (±SD) total protein in the women 45.10 (±12.55) and carbohydrate 212.83 (±36.97) in the men. The energy contribution indicated 98.3 percent (n=58) men and 85.72 percent (n=158) women consumed <100 percent of the EER for viii energy. However, the findings from the Top 20 food items measured by the 24-Hour Recall indicated that this community’s diet is largely carbohydrate-based, containing primarily starchy staple foods, sufficient intake of animal products, and insufficient intakes of dairy foods, fruit and vegetables, possibly resulting in the micronutrient deficiencies. The energy distribution of the macronutrients from the average of both 24-Hour Recalls indicates that both men and women are in range of 15-30 percent total fat intake, 10-15 percent protein and 55-75 percent carbohydrate. Conclusion: The results of the study reflect that the elderly in this community are faced with poverty, food insecurity as well as social factors thus contributing to a compromised nutritional status. The progression of malnutrition in particular overnutrition is experienced by the majority of the respondents in this study, however, an increased BMI and the prevalence of hypertension is a risk marker for noncommunicable diseases. However, the high prevalence of inadequate food and nutrient intake amongst elderly discloses the need for nutrition interventions and should be aimed at modifying the elderly food choices when purchasing food, healthier food preparation methods, increasing fruit and vegetable portions and improving daily physical activity to attain a better quality of life.
Barriers and facilitators of brown rice consumption, sensory acceptability and its effect on blood glucose level among university staff
(2021) Reddy, Anjellah; Naicker, Ashika; Singh, Evonne
Background: South Africa is undergoing an epidemiologic and nutrition transition, characterized by a surge in the prevalence of overweight and obesity levels, with a noticeable increase in the consumption of high energy-dense, low nutritive foods and beverages, and a marked decrease in physical activity. Food consumption patterns in South Africa have changed dramatically over the past decades, and will most likely continue to transform over the coming decades. Diabetes is on the rise in South Africa, and a significant body of evidence suggests that targeted interventions, such as the inclusion of whole grains and a plant-based diet, are beneficial towards lowering blood glucose levels. A shift to substitute white rice with brown rice, and to increase awareness on the impact of brown rice consumption, can be a solution towards enabling behaviours aimed at subsequently maintaining and lowering blood glucose levels among adults. However, this can only happen if barriers and facilitators of brown rice consumption are identified and addressed. Additionally, pairing brown rice with meals typically enjoyed by a target population may increase acceptability of brown rice inclusion in the diet. Aim: The purpose of this research was to determine barriers and facilitators of brown rice consumption, and the sensory acceptability of brown rice when paired with typical South African dishes, lastly, to measure the effect of a brown rice meal on blood glucose level among staff members of the Durban University of Technology (DUT). Methodology: The study used a mixed methods approach; qualitative methods were used to assess the barriers and facilitators of consuming brown rice through three focus group discussions (FGDs). A quantitative method approach was applied to assess the sensory acceptability, appropriateness, and palatability of paired meals with brown rice. A selection of measuring tools and techniques were utilized, namely, FGDs, starch food frequency questionnaire (SFFO); sensory acceptability tests of brown rice cooked using various methods; sensory acceptability tests of brown rice paired dishes; anthropometrics and clinical measurements of participants, and pre-prandial and 2-hour post-prandial blood glucose measurements. Results: Three FGDs were conducted until meaningful saturation was reached; two face-toface and one in the online mode. The total number of participants in the three FGD groups consisted of 24 participants, comprising of 25% (n=6) men and 75% (n=18) women participants. Five broad themes were identified: perceptions of healthy and unhealthy foods, factors that determine food choice, factors that influence rice choice, barriers, and facilitators of including brown rice in the diet. The FGDs outlined the following barriers: brown rice is not as tasty as white rice; it requires a longer cooking time; participants had limited preparation skills; brown rice is expensive, and the designated family shopper purchases only white rice. On the other hand, facilitators of brown rice consumption included favourable sensory attributes such as crunchy mouthfeel, nuttiness, non-sticky texture and an earthy aroma. The SFFQ was administered to 94 Durban University of Technology participants who work at the institution. Significantly, the most frequently consumed starch was potatoes, where 63.8% of the study participants had eaten potatoes in the previous 7 days (p=.010). This was followed by brown bread (48.7%) and white parboiled rice (42.6%). In the total rice category, 89.4% of participants reported consuming rice, of which brown rice was the least consumed (11.7%). This alluded to a strong potential to shift from white to brown rice consumption if barriers could be overcome. For the sensory acceptability tests of brown rice paired dishes, two meals, butter chicken and lamb curry, were paired with brown rice. A strong liking was shown for both these paired meals when examining all sensory attributes (appearance, taste, smell and texture) with brown rice. The sensory evaluation (n=60) of butter chicken paired with brown rice using the 9-point hedonic scale showed that taste had the highest ranking of 7.97, followed by appearance at 7.95, texture at 7.90 and smell at 7.82. The sensory evaluation (n=60) of lamb curry paired with brown rice showed that appearance had the highest ranking at (7.87), followed by texture at (7.69), taste at (7.67) and smell at (7.52). Four different cooking methods were used to cook brown rice, namely, stove-top, gas, microwave and oven. Although brown rice prepared using microwave cooking was most preferred at (28.8%), the chi-square goodness-of-fit test showed that all four cooking methods were equally preferred (p=.834). The anthropometric results showed that the (n=51) mean waist circumference (WC) for both men and women in this study was higher than the recommended WC cut-off points. The anthropometric status in this study denotes that high WC places participants in this study at a greater risk of chronic diseases. The anthropometric measure for weight (n=58), one participant was underweight (1.15%); 28.4% (n=25) participants were normal weight; 35.22% (n=31) participants were overweight, and 35.23% (n=31) participants were obese. The anthropometric for height (n=58) in centimetres was indicated at 1.60 for women and 1.71 for men. After participants observed an overnight fast, (n=60) the mean pre-prandial blood glucose level was 5.54 mmol/L, 2 hours after consuming a healthy brown rice breakfast, the mean post-prandial blood glucose was 5.45 mmol/L. Analysis from a Wilcoxon signed ranks test showed that there was no significant difference in blood pre to post eating, (p=.771). Analysis using a paired ttest showed that there was no significant difference in blood values before and after eating, (p=.431), meaning that blood glucose levels were maintained after consuming the brown rice breakfast. The findings of this result endorse the healthful benefits of brown rice, as it is widely evidenced in existing literature that brown rice reduces insulin spikes and aids in the stabilisation of the body's blood sugar levels due to its low glycaemic index. There is potential to shift participants from white to brown rice however, this can be facilitated by deliberately pairing brown rice with dishes most preferred by the target population. Once palates become more accustomed to brown rice, it may be easier to encourage brown rice consumption with other dishes. No significant differences in post-prandial blood were found across the Body Mass Index (BMI) categories, F (3, 51) (p= .970, p=.414). However, there was a significant moderate positive correlation (r=.365) between WC and post-prandial blood scores, (p=.011) alluding to the risk factor association of increased WC and blood glucose levels. Conclusion: The health benefits associated with brown rice consumption as outlined in this research, warrants that further research be conducted on the acceptance of brown among consumers in South Africa. The favourable acceptance of brown rice when paired with butter chicken, lamb curry; egg fried rice and breakfast muesli concept as depicted in this study, indicates scope for a much larger percentage of brown rice consumption than the current 11.7%. It also alludes to the importance of contextualising meal combinations and sensory acceptability, to fit specific contexts and thus influence consumption patterns. Shifting individuals starch preference to more healthful starches, like brown rice, can contribute to health gains for a target population. Alongside this, consumer education, recipes and sensory sampling can help consumers feel part of the solution. Many studies have documented the healthful benefits of making the transitional shift from white rice to brown rice. However, this study notes despite its healthful benefits, that the acceptance of brown rice has been limited, compelling the activation of consumer education and practical preparation solutions to ease consumer acceptance of brown rice.
Biochemical characterization of selected carbohydrases from Beauveria bassiana and their potential applications
(2021-07) Amobonye, Ayodeji Emmanuel; Pillai, Santhosh Kumar Kuttan; Singh, Suren
Different filamentous fungi have continued to attract scientific interests as novel sources of enzymes and other important bioproducts. Beauveria bassiana, a well-known entomopathogenic fungi has long been valued for its biotechnological application as a biocontrol agent in its entomopathogenic state and as a plant-growth promoter in its endophytic state. The fungus has also been proven to be safe for human health, as studies have shown B. bassiana strains to be non-pathogenic to humans, other animals and plants. Furthermore, its ability to utilize various agro-residues for its growth and the concomitant production of important bioproducts have been well demonstrated. However, despite all of these, there has been no appreciable attempt at exploring this remarkable fungus for the production of industrially important enzymes, especially in its saprophytic state. Recently, a filamentous fungus was isolated in its endophytic state from onion leaves, in our laboratory. It was confirmed by rDNA ITS sequencing to be a B. bassiana strain and was subsequently designated as B. bassiana SAN01. Preliminary experiments revealed the remarkable ability of this novel strain to utilize lignocellulosic biomass for its metabolism while secreting various biomass-degrading enzymes in the process. Hence, carbohydrases from B. bassiana SAN01 were considered worthy of investigation because of the established safety of the source organism, as well as the probable low production cost of the enzymes using readily available plant biomass. Besides, it was also observed that there has been no significant investigation into the biochemical properties of lignocellulolytic enzymes from B. bassiana, which has probably hindered their industrial applicability. Hence, this Ph.D. research was focused on investigating the production, the biochemical properties, as well as the potential applicability of selected biomass-degrading enzymes, viz., amylase, cellulase (endoglucanase), pectinase (polygalacturonase) and xylanase from B. bassiana SAN01. To achieve these, the phylogenetic relationship of the fungal strain was established, and its carbon utilization profile was annotated using phenotypic microarray technology. Furthermore, to understand the dynamics surrounding its lignocellulosic biomass utilization and its carbohydrase-production capabilities, comparative transcriptomics analysis was carried out B. bassiana SAN01 under three different simulated conditions i.e., endophytic, fermentation and lab control conditions. In addition, to fully explore the carbohydrase production potential of the fungus, the production of the selected carbohydrases was optimized using response surface methodology; subsequently, all the selected enzymes were purified to enhance the evaluation of their biochemical properties as well as their potential industrial applications. The proclivity of B. bassiana SAN01 for polyols, pentoses, N-acetyl-D-glucosamine and some other carbon sources was demonstrated by the phenotype microarray profiling. While the comparative genome-wide transcriptome analyses revealed a clear distinction between the fungus under the different trophic conditions investigated. It was observed that 4-5% of the 10,365 B. bassiana SAN01 genes were differentially expressed between these conditions, and a significant proportion of the genes were found to be involved in lignocellulose deconstruction. The annotation of CAZymes from the B. bassiana SAN01 transcriptome under fermentation (saprophytic) conditions confirmed the upregulation of biomass-degrading enzymes such as amylases, cellulases, chitinases, glucanases, laccases, lignases, pectinases and xylanases. The subsequent optimization of the production parameters of B. bassiana SAN01 amylase, endoglucanase, polygalacturonase and xylanase led to heightened yields of 34.82 UmL-1, 23.03 UmL-1, 51.05 UmL-1, and 1061 UmL-1, respectively. These were estimated to be 1.79-, 1.35-, 1.87- and 3.44- folds higher than unoptimized production levels and are also the highest ever production levels recorded for these enzymes from any B. bassiana strain. Further in the study, the xylanase from B. bassiana SAN01 was purified to homogeneity while the other three enzymes were partially purified. The purified xylanase was demonstrated to have a molecular mass of ~37 kDa and performed optimally at pH 6.0 and 45oC. However, the optimum pH of the partially purified amylase, endoglucanase, and polygalacturonase were found to be pHs 6.0, 6.0 and 7.0, while the optimum temperatures were observed to be 35oC, 35oC and 45oC, respectively. Consequently, the purified B. bassiana SAN01 xylanase was demonstrated to be effective in deinking wastepaper with an optimized deinking rate of 106.72% relative to the control. In addition, the partially purified amylase-polygalacturonase from B. bassiana SAN01 was demonstrated to adequately clarify pear juice with a 1.37-fold improvement in clarity recorded under optimal conditions. Furthermore, results also showed that the enzymatic- assisted juice clarification was without any detrimental effect on some quality parameters of the juice. In the same vein, crude endoglucanase-xylanase from the fungus was shown to significantly hydrolyze sugarcane bagasse, releasing ~20% reducing sugars under optimal conditions. Finally, to gain insights into the structure-function relationship of B. bassiana carbohydrases, the structural properties of B. bassiana chitinases and xylanases were elucidated for the first time using computational techniques. The in silico prediction revealed that the enzymes were generally hydrophilic, thermostable, negatively charged and extracellularly secreted. The modelled tertiary structures of B. bassiana chitinase and xylanase were validated by the presence of ~ 90% of their amino acid residues in the Ramachandran plot’s favoured region. The findings from this study have thus created a strong framework for the prospective utilization of B. bassiana and its carbohydrases in alternative biotechnological processes.
Biodiesel production from microalgae by enzymatic transesterification
(2015) Guldhe, Abhishek; Bux, Faizal; Permaul, Kugen; Mutanda, Taurai
Main focus of this study is to investigate the enzymatic-conversion of microalgal lipids to biodiesel. However, preceding steps before conversion such as drying of microalgal biomass and extraction of lipids were also studied. Downstream processing of microalgae has several challenges and there is very little literature available in this area. S. obliquus was grown in the pilot scale open pond cultivation system for biomass production. Different techniques were studied for biomass drying and extraction of lipids from harvested microalgal biomass. Effect of these drying and extraction techniques on lipid yield and quality was assessed. Energy consumption and economic evaluation was also studied. Enzymatic conversion of microalgal lipids by extracellular and whole cell lipase application was investigated. For both applications, free and immobilized lipases from different sources were screened and selected based on biodiesel conversion. Process parameters were optimized using chosen extracellular and whole cell lipases; also step-wise methanol addition was studied to improve the biodiesel conversion. Immobilized lipase was studied for its reuse. Final biodiesel was characterized for its fuel properties and compared with the specifications given by international standards. Enzymatic conversion of microalgal lipids was compared with the conventional homogeneous acid-catalyzed conversion. Enzymatic conversion and chemical conversion were techno-economically investigated based on process cost, energy consumption and processing steps. Freeze drying was the most efficient technique, however at large scale economical sun drying could also be selected as possible drying step. Microwave assisted lipid extraction performed better compared to sonication technique. Immobilized P. fluorescens lipase in extracellular application and A. niger lipase in whole cell application showed superior biodiesel conversion. The extracellular immobilized P. fluorescens lipase showed better biodiesel conversion and yields than the immobilized A. niger whole cell lipase. Both the enzyme catalysts showed lower biodiesel conversion compared to conventional chemical catalyst and higher processing cost. However, techno-economic analysis showed that, the reuse potential of immobilized lipases can significantly improve the economics. Fewer purification steps, less wastewater generation and minimal energy input are the benefits of enzymatic route of biodiesel conversion. Microalgae as a feedstock and lipase as a catalyst for conversion makes overall biodiesel production process environmentally-friendly. Data from this study has academic as well as industrial significance. Conclusions from this study form the basis for greener and sustainable scaling-up of microalgal biodiesel production process.
Biodiversity of anaerobic cellulolytic bacteria in landfill sites
(2001) Goldstone, Loren; Tivchev, G. N.
Landfills play an important role in the removal of waste from the surroundings. There is a limit to the types of waste that can be recycled and the landfill becomes the final method of waste disposal. Because waste constitutes a wide variety of materials, the microbial consortia that develop within a landfill will be equally varied, depending on the type of waste deposited, the temperature of the landfill and moisture content of the waste. The metabolism of these microbial consortia can result in products that are either harmful or beneficial. In order to increase the pool of knowledge on landfill microbiology, it is important to study the various consortia that inhabit the landfill to determine the various microbial interactions that occur and subsequently to manipulate these interactions to enhance the benefits of a landfill site and reduce the harmful effects. In this research, an attempt was made to isolate anaerobic cellulolytic bacteria from a landfill site. Six waste samples, varying in age were obtained over a period of two years. Samples were excavated from a maximum depth of 4m. Samples are processed in anaerobic, phosphate buffer and cultivated in various pre-reduced anaerobic media and incubated under anaerobic conditions. Samples were also collected from other potential anaerobic sites namely, anaerobic sludge, decomposing bagasse, compost, manure, rumen and pond sediment. Results of degradation of the cellulose source (Whatman No. 1 filter paper) indicated that it was possible to cultivate cellulose-degrading microorganisms from the landfill. Zones of clearing around colonies, which would be indicative of cellulose degradation on solid media, were not obtained. Samples from the anaerobic sludge, compost and rumen showed degradation of cellulose in liquid media but not on solid media. It is concluded that the solid media used was unsuitable for the cultivation of anaerobic, cellulolytic bacteria or that the anaerobic conditions employed were not adequate to initiate the growth of the anaerobic cellulolytic bacteria.
Chemoprotective action of natural products on cultured human epithelial cells exposed to aflatoxin B1
(2005) Reddy, Lalini; Odhav, Bharti
Previous studies indicate that a mutation in the non-oncogenic p53 gene is epidemiologically linked to human HCC (Ozturk, 1991; Chan et al., 2003). Hsu et al. (1991) found this link in Chinese, South African and Asian patients and Hollstein et al. (1993) found the same gene mutation in Taiwanese patients. The incidence of these aberrations is reported to be about 20- 50% in HCC’s (Kishimoto et al., 1997). There is sufficient evidence to indicate that carotenoids in addition to their well known antioxidant properties (Paiva and Russel, 1999), also affect intercellular communication, immune responses, neoplastic transformations and growth control, and cellular levels of enzymes that detoxify carcinogens (Zhang et al., 1991; Brockman et al., 1992; Pryor et al., 2000). To date studies carried out have used the rat (Foote et al., 1970; Gradelet et al., 1998) and the mule duckling model (Cheng et al., 2001) to show the protective effect of these carotenoids against AFB1 exposure. Of the well known carotenoids, lycopene and beta- carotene occur in abundance in fruits and vegetables and are safe for human consumption. Aflatoxin B1 frequently induces mutations of the p53 gene which is linked to HCC. Although there is much evidence from epidemiological studies linking the beneficial aspects of carotenoids to the prevention of cancer, the cellular and molecular mechanisms need to be understood in order to implement large scale intervention strategies to prevent AFB1 induced carcinoma. The use of chemical or dietary interventions to alter the susceptibility of humans to the actions of carcinogens and to block, retard or reverse carcinogenesis is an emerging chemoprotective strategy for disease prevention (Abdulla and Gruber, 2000; Kensler et al., 2003; Bingham and Riboli, 2004). Chemoprotection by natural products involves maintaining cellular integrity, preventing DNA alterations, activation of p53 suppressor protein and apoptosis. The aim of this study was thus to investigate the cellular and molecular mechanisms by which beta-carotene and lycopene may prevent the AFB1-induced toxic changes in human hepatocytes. In order to achieve this aim, the following objectives were set out: i. To optimise an in vitro system for the evaluation of AFB1 damage to cultured hepatocytes. ii. To determine the biochemical protection offered by beta-carotene and lycopene to AFB1-exposed hepatocytes, by measuring the mitochondrial activity, cell viability and ROS levels using appropriate enzyme assays and flow cytometry. iii. To determine the cellular protection offered by beta-carotene and lycopene to AFB1-exposed hepatocytes, by studying the morphological changes at the structural and ultrastructural levels using phase contrast light and electron microscopy respectively. iv. To determine the molecular protection offered by beta-carotene and lycopene to AFB1-exposed hepatocytes, by detecting apoptotic bodies as genomic markers and measuring the levels of p53 protein and AFB1-N7-guanine adducts produced.
Cytotoxicity and gene expression of selected apoptotic markers in the human laryngeal carcinoma cell line (HEp-2) by Bulbine spp. fractions
(2013-07-30) Singh, Rishan; Reddy, Lalini; Permaul, Kugen
Apoptosis, or programmed cell death, is a process which is pivotal in eliminating damaged, infected, or unwanted cells from the body. It has been studied in numerous types of cell lines ranging from normal to infected cell lines, and there have been a wide range of studies on apoptosis in laryngeal cancer because this type of cancer has become one of the most common types of head or neck cancer due to the high incidence of alcohol consumption, tobacco smoking and chewing of betel quid amongst populations. Laryngeal cancer is usually treated with radiotherapy or is surgically removed, but due to the loss of the function of the larynx after surgery, it has been suggested that alternative strategies or ways of treating laryngeal cancer are required. This has prompted the use of, and research in the field of, plant medicine to combat laryngeal cancer. Plant medicine has been used for centuries by the Chinese, Indian and Arabian population in Uhani, Ayurveda and Siddha as a form of replacing conventional medicine with complementary and alternative medicine, these include many plants from the family Asphodelaceae, which have become marketable commodities owing to their medicinal values and traditional uses. Amongst these plants, the genus Bulbine has been used as a form of natural medicine in rural Africa and they are also exploited for their aloe vera properties as well as their possession of phytochemical compounds such as isoflavanoids, nor-lignans, naphthalene derivatives, anthracene and poly prenylated flavonoids. There has been a compelling amount of literature on the traditional uses of the Bulbine spp. because these are linked to the Bulbine spp. having secondary metabolites such as pyroles, chromones, coumarins, bianthraceane, benzene as well as alkaloids. However, for Bulbine natalensis and B. frutescens, the plants of interest in this study, the location of anticancer compounds in them are the only amounts of information available. It has been reported, traditionally, that B. natalensis possesses the anticancer potential in the roots, while the anticancer potential for B. frutescens is in the leaves. However, this requires scientific clarification. Therefore, this study was conducted to assess programmed cell death or apoptosis by analysing the responses of the human laryngeal carcinoma cell line (HEp-2) to crude aqueous and organic (50% and 100% ethanol) fractions of B. natalensis and B. frutescens. In order to have achieved this, the HEp-2 cell line was exposed to the above mentioned fractions at three different final concentrations (20, 2 and 1μg/ml) and assessed for cytotoxicity using the 3-(4,5- dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cytotoxicity assay as an indicator of cell death after fraction utilisation (3 days) for 5 and 8 days. The differences in the potency of the Bubline spp. fractions were confirmed using the non-parametric ANOVA test. Thereafter, selected fractions were screened for apoptotic potential using reverse transcriptase-polymerase chain reaction (RT-PCR) to determine the expression of bax and caspase-3 biomarkers, which are the biomarkers that participate in mitochondrial, endoplasmic reticulum and receptor-ligand mechanism of apoptosis. The fractions of B. frutescens were selected relative to those of B. natalensis for the RT-PCR procedure (read section 3.4.1. for the selection procedure) and links between the cytotoxicity and gene expression results were analysed. It was found that the B. natalensis fractions had a much greater cytotoxic effect on the HEp-2 cell line compared to fractions of B. frutescens by the fifth day of the MTT assay. On the eight day of incubation, there was an increase in HEp-2 cell line proliferation by the fractions of both plant species administered. The fractions selected for bax and caspase-3 gene expression analysis for B. natalensis were the: 20 μg/ml root and corm aqueous fractions, 20 μg/ml leaf and corm 100% ethanol fractions, 20 μ g/ml corm 50% ethanol fraction, 2 μg/ml root aqueous fraction, 2 μg/ml leaf 100% ethanol fraction and the corm 1 μg/ml aqueous and 50% ethanol fractions. The fractions that were compared to B. natalensis were the 20 μg/ml root and leaf aqueous and 100% ethanol fractions respectively, the 2 μg/ml root aqueous fraction and the 2 μg/ml leaf 100% ethanol fraction. It was found from RT-PCR analysis that all of the B. natalensis fractions tested induced expression of caspase-3, which indicated that those fractions were capable of inducing apoptosis in laryngeal carcinoma in vitro, since caspase-3 is the molecular indicator of apoptosis. The aqueous B. frutescens root fraction, did not induce expression of caspase-3 gene, although it caused expression of bax. This implied that the root aqueous B. frutescens fraction, may be involved in some other form of cell death, other than apoptosis. It was also found that there was variability in the response of the HEp-2 cell line to the Bulbine spp. fractions because of the variation in bax expression among fractions of different concentration. It was difficult, from this study, to classify fractions into categories for their mechanism of action, because not all of the fractions that caused the expression of capase-3, induced bax gene expression. Hence, proper conclusions were unable to be made, more so, because all the mechanisms of apoptosis mentioned, involve bax gene activation in order to proceed to completion. Therefore for those Bulbine spp. fractions to which the HEp-2 cell line exhibited a variable response to, it was postulated that cell death or apoptosis occurred through some other unknown mechanism. Overall, the cytotoxicity result didn’t correlate to the gene expression results because fractions that promoted HEp-2 cell line growth by day five, expressed apoptotic markers, which highlighted the sensitivity and accuracy of the cells-to-cDNATM II kit for detecting a few possibly apoptosed cells. This was confirmed by the fact that the HEp-2 cell line used in the MTT cytotoxicity assay and gene expression study had the same passage number and were viable, the latter being achieved because the MTT assay only measures the cytotoxicity of compounds once they have been taken up by viable cells – measuring mitochondrial activities expressed as absorbances. Therefore, the deduction that HEp-2 cell death may be due to bax/caspase-3 expression was valid because the mRNA was isolated from viable HEp-2 cells that had been killed by Bulbine spp. fractions of different polarity. Furthermore, the lack of correlation between the cytotoxicity and gene expression results indicated the amount of HEp-2 cell line proliferation by the fraction out-competes those that died, thereby producing a negative cytotoxicity result. There was a relationship between the traditional information about the anticancer potential for B. natalensis and B. frutescens. For example, the aqueous root fractions of B. natalensis were found to be non-toxic to the HEp-2 cell line, but did express caspase-3, which indicated the possibility of apoptosis. Similarly, the 100% ethanol leaf B. frutescens fractions were non-toxic to the HEp-2 cell line, but were able to induce apoptosis as well. This emphasised that the MTT cytotoxicity assay should be compared with other methods of measuring cytotoxicity when performing studies like this, because although literature has emphasised many advantages of using the MTT cytotoxicity assay in apoptotic studies, this study proved otherwise. When identical HEp-2 cells were treated with the same extract, only some cells were killed (apoptosis) whereas others proliferated. This was because although the cells were identical phenotypically, they were all probably at different phases of the cell cycle resulting in the HEp-2 cells responding variably to the same fraction at different concentrations. It was also found that the responses were concentration independent. For example, the 1 μg/ml B. natalensis corm fraction exhibited the highest toxicity of the three concentrations administered. The lowest cytotoxicity was achieved for the 20 μg/ml fraction – showing a proliferative effect on the HEp-2 cell line. Similarly, the 2 μg/ml aqueous B. natalensis leaf fraction induced the highest cytotoxicity level in the HEp-2 cell line followed by the 1 μg/ml and then the 20 μg/ml fractions. Apart from the genetic variation in identical HEp-2 cells; this indicated that the HEp-2 cell line was selective to particular fractions of the Bulbine spp. for utilisation. Concentration independence and HEp-2 cell preferential selection has been reported in many other studies involving plant fractions/extracts and natural products. This study demonstrated that although all the tested B. natalensis fractions were capable of inducing HEp-2 cell death possibly via. apoptosis (caspase-3 induction), a lack of any link between apoptosis and the cytotoxicity results (hence the 20 μg/ml corm fraction had a negative cytotoxicity but expressed both apoptotic markers), indicated the need for phytochemical screening of both Bulbine spp. in future, to determine the compounds that are responsible for the cytotoxicity and gene expression result outcomes of both Bulbine spp. fractions. Furthermore, procaspase genes also have to be analysed since genes are expressed to form procaspases, which then form active caspases. Although normal cells also express caspase-3 genes during apoptosis, this study focused exclusively on the effect of Bulbine natalensis and B. frutescens fractions (selected relative to the cytotoxicity results of B. natalensis) on the HEp-2 cell line (read cell culture and cytotoxicity discussion for selection of HEp-2 cell line). The validity of this study is confirmed by similar experimental designs that assayed the cytotoxicity of plant-derived or natural compounds on cancer cell lines only, and the detection of apoptosis through caspase- 3 induction and other unrelated methods. This is the first study to report the induction of apoptosis in cancer cell lines by Bulbine spp. fractions using cytotoxicity and the expression of bax and caspase-3 apoptotic markers. It provides insight into the interaction between the HEp-2 cell line and the aqueous and organic fractions of B. natalensis and B. frutescens by analyzing links between cytotoxicity and bax and caspase-3 gene expression; which could probably contribute to drug design with selected Bulbine spp. fractions. Further investigations are required in future, to confirm the possible drug targets of the studied Bulbine spp. fractions in an attempt of assaying their therapeutic importance.
Determining nutritional status and food intake patterns of pre-school children in Empangeni, South Africa
(AJHTL, 2016) Mwadiwa, R.J.; Kearney, J.E.; Napier, Carin E.
The major goal of the assessment was to establish the prevalence of child malnutrition in two sampled pre-schools, in order to determine the resources and approaches required for an appropriate response to the concern, and with a view to finding sustainable solutions. The means of anthropometric measurement tools concurrently with socio-demographic and food frequency questionnaires were applied in conducting the survey to evaluate the food intake patterns of the 1-3 year old pre-school children. The cross-examination of the pre-school cycle menus was analysed. The combined results of the tools applied in data collection were also used to classify nutrient deficiencies of the sample group as well as detecting specific dietary requirements comparing with the World Health Organisation’s standards. The findings of the assessment showed that malnutrition was prevalent among the 1-3 year olds in the sampled pre-schools and that these conditions resulted from persistent household and pre-school food insecurity in quantity, quality and diversity. The food intake patterns were inconsistent as in some instances children consumed either high or low intakes of macro or micro nutrients and that consumption habits were incompatible with required nutrient RDAs per child. The ultimate objective of the assessment was to form the core for implementing a more in-depth experimental study aimed at scientifically developing novel food products out of integrating traditional and modern processed foods. The researcher’s primary objective is to improve the pre-school feeding menus in the hope of adding value to the nutritional status of the target population.
Development and acceptability of a cost-effective, energy-dense snack suitable for the National School Nutrition Programme
(2020-11-13) Hassanally, Saffia; Naicker, Ashika; Singh, Evonne
Background: The National School Nutrition Programme (NSNP) was established in South Africa (SA) to ensure that hunger will not be a barrier to learning among school learners attending quintile one to three schools and aims to provide a free, nutritious meal for all 189 school days. The NSNP currently does not have a solution to ensure that all learners are suitably sustained until the main NSNP meal can be served. With the increase in food insecurity levels, the need for the development of an energy-dense snack item for school learners is critical, in the effort of combatting hunger and ensuring learners have the necessary energy to sustain their concentration until their next meal. Aim: This study aimed to develop a suitable, cost-effective, energy-dense snack item for learners as a supplement to the NSNP, to assist learners in reaching their recommended dietary requirements. Methodology: The snack product development was informed by a cross-sectional snack preference survey, as well as a scoping review of the literature on school feeding programmes and past snack interventions that have shown success in South Africa and other developing countries in Africa. Through informed consent, 85 primary school learners between the age group of nine to thirteen that were part of the NSNP from two quintile three schools in KwaZulu-Natal participated in the snack preference survey whilst 81 learners participated in the consumer sensory evaluation. The snack preference survey and scoping review of past snack development interventions were conducted, to decide on a suitable, cost-effective snack for development, for the learners of the primary schools. The developed snack product then went through sensory evaluation, using trained personnel and, thereafter, for microbiological testing, to deem the product safe for consumption. The product then underwent nutritional analysis, to determine the nutritional properties of the snack item and shelf-life testing. Lastly the product was presented to the learners for final sensory analysis, to determine sensory acceptability of the developed snack, using a 7-point facial hedonic scale. Results: Analysis of the reviewed articles inferred that the most appropriate snack product to develop for this study was a biscuit. Results from the snack preference survey showed that muffins were the most preferred snack (57.1%) by both girls and (55.8%) boys, respectively. Biscuits were the second most preferred snack (32.6%) by both girls and (33.3%) for boys, respectively. There was no significant relationship between gender and choice of snack (p=1.000) and no significant relationship between age and choice of snack (p=0.141). The literature results showed biscuits to have a longer shelf life than most other snacks. It can be emulated with ease and can carry many nutrients, while being cost-effective. Trained sensory panellists, comprising of consenting Food and Nutrition staff and students, were used to evaluate the sensory acceptability of the trial recipes, during development. Following the systematic steps of food product development, at the end of the trained sensory tests, a crispy, flavourful biscuit was developed. The final recipe yielded 20 portions of 22g biscuit dough, of which the final weight of the biscuit was reduced to 20g, due to moisture loss during baking. The microbial analysis deemed the product to be safe to consume, as total counts of coliform bacteria were zero, showing no bacterial growth. The nutritional analysis showed that fat contributed the most energy (61.0%). The Recommended Dietary Intake (RDI) percentage values of the biscuit amounted to 14.3% for girls and 14.2% for boys, which is in-keeping with the first objective of creating an energy-dense product. When compared to two other products of a similar nature on the market, the developed biscuit was found to be the most cost-effective (R0.79 for 20g portion). The shelf stability of the product proved that the product is highly shelf stable, remaining fresh for five weeks and can last up to five months, under proper storage conditions. Following the consumer sensory evaluation, a significant number (69.1%) of children found the snack to be ‘Super good’ (p<.0005), 14.8% rated the product as ‘Good’ and 12.3% rated the product as ‘Really good’. There was no significant difference in sensory scores across age groups (p=0.706). Conclusion: It is well established that school feeding programmes create a positive impact on school children, as it enriches their lives and provides them with much needed nutrients. In SA, the well-established NSNP does have challenges one of which is the shortfall of -providing 30.0% of the Recommended Dietary Allowances (RDA) to learners. Although there are existing snack development studies, this study is unique, in the sense that it is designed to assist the NSNP to fill the current gap in the RDA for the children of SA. All objectives of this study were reached, and a suitable, cost-effective, energy-dense snack biscuit was developed in a systematic process. This snack can be a potential solution to sustain children that come to school hungry. This study will be brought to the attention of NSNP stakeholders, in the hope of the programme adopting this solution, to fill the RDA gap in the NSNP.
Development of a protocol for the micropropagation of mature Eucalyptus grandis clones through somatic embryogenesis
(2001) Tsewana, Andiswa; Watt, Maria Paula
Biotechnology techniques such as micropropagation VIa somatic embryogenesis offer potential significant advances in the improvement of forest species, which could sustain forest production in South Africa, as well as globally, without increased use of land. In order to apply such techniques to commercial breeding and clonal programmes of E. grandis species, it is necessary to develop reliable and efficient protocols applicable to explants of proven superior genotypes. Most of the research on E. grandis somatic embryogenesis has used the genetically variable embryos or seedlings as explant sources, which results in the propagation of material of unproven genetic value. In order to exploit somatic embryogenesis maximally for cloning of superior trees, somatic embryos have to be induced from highly selected and, hence, mature trees. The aim of this investigation was to develop such a protocol for E. grandis and to test its applicability to various E. grandis hybrids. Somatic embryos were induced from buds, stems, leaves and petioles, with petioles and buds giving the best results. Thus, these were selected for further studies which involved testing the effect of medium composition on embryogenic callus induction. Media used for this purpose contained MS or B5 nutrients, 1 mg.l' 2,4-D, 0.5 g.r! glutamine, 0.5 g.r! casein hydrolysate, 4 g.r! Gelrite and 30 or 50 g.rl sucrose. All the media tested were able to support induction of embryogenic callus, although the number of explants producing embryogenic calli was affected significantly by the media composition (10-91 %). Callus induction media with B5 nutrients seemed to have a significant effect onn the developmental stage of embryos in the callus induction medium. Presence of 50 g.r! sucrose in the callus induction medium reduced the embryo yield, but the progress of embryo development was enhanced. The callus induction medium containing B5, 1 mg.l' 2,4-D, 0.5 g.rl glutamine, 0.5 g.r! casein hydrolysate, 4 g.r! Gelrite and 30 g.l' sucrose was chosen for subsequent studies. Of all the media tested for embryo development, the medium with B5, 2.5 mg.l' 2iP, 0.5 g.r! glutamine, 0.5 g.r! casein hydrolysate, 4 g.r! Gelrite and 50 g.r! sucrose was found to be the most suitable for embryo development to the cotyledonary stage. Experiments involving incorporation of both ABA and 2iP aiming at maturation of E. grandis somatic embryos led to an increase in size of the cotyledonary embryos formed but not to germination.
Development of objectives for an educational programme to improve consumer knowledge of and attitudes towards nutritional information on food labels
(1994) Anderson, Diana Jane; Coertze, Dirk J.
Much attention has been given to the prevalence of diseases related to over-consumption of food, with nutritional labelling playing an increasingly prominent role in the prevention and reduction of these diseases. The development of technology and the subsequent availability of processed food have greatly contributed to these diseases, and created gaps in both distance and concept between the consumer and the manufacturer. An increasing number of food manufacturers are providing nutritional information regarding their products in order to maintain their position in the market; however, this avalanche of information is outstripping the ability of the consumer to use it effectively or to even comprehend it. This study was undertaken to identify the objectives needed for the formulation of an educational programme concerning the nutritional labelling of food containers.
The effect of seasonal food variety and dietary diversity on the nutritional status of a rural community in KZN
(2014-08-07) Nsele, Nelisiwe; Napier, Carin E.
Introduction: Dietary diversity is an indicator of access and measurement of household food security as it relates to income, location and seasonality. Dietary diversity is measured by physically counting the number of individual foods as well as food groups consumed over a given reference period. When dietary diversity is accurately measured, nutrient adequacy will be easily predicted. In order to measure dietary diversity accurately, it is important to determine household food security. Insufficient food and resources often result in food insecurity which leads to little or no dietary diversity. Poor populations suffer most from achieving dietary diversity because they consume a standard diet based on starchy staple food with limited fruits and vegetables resulting in multiple nutrient deficiencies. Rural communities rely on seasonal food variety in order to obtain fruits and vegetables needed by the body to limit nutrient deficiencies. Some seasons are more productive than others. Rural communities also use various coping strategies to deal with food insecurity in all four seasons. High levels of unemployment as well as a lack of nutrition education results in most rural households unable to cater for dietary diversity. Aim: The aim of the study is to determine the effect of seasonal food variety, dietary diversity and nutrient adequacy on the nutritional status of women in rural areas. Method: A hundred women in this community were weighed and measured and BMI determined and classified according to the WHO cut-off points for BMI. Waist circumference was measured in order to determine the waist-to-height ratio indication risk of metabolic syndrome. Twenty four hour recall questionnaires were used to determine actual intake compared to dietary reference intake (DRIs). Food Frequency Questionnaires for a period of seven days were completed captured and analysed using the SPSS version for descriptive statistics in order to determine food diversity. Coping strategies were determined by Focus Group interviews with community members in order to identify the various strategies used in time of food shortages. The severity of these strategies was determined by the community. Seasonal food consumption patterns and dietary intake behaviour were assessed over the four seasons. The highest frequency score (7) x severity weight (1-4) x10 strategies = maximum score of 140. Thus the higher the score the more food insecure the community is. Results: Food production from crops differs in different seasons. Food insecurity is high in summer and autumn due to a low number of food items harvested from crops. The community cope less in summer and autumn due to less crops available. The community is more food insecure in spring and winter due to the high number of food items harvested from crops. The community cope better in winter and spring due to the high level of available crops. Anthropometric measurements indicated that 41.2% of women between 31 and 50 and 49% of women between 51 and 70 years of age had a BMI of 30 and above. About 44% of total women are obese and 29% are pre obese. Only 26% had a normal weight. The 24 hour recall analysis indicates that the high level of obesity is due to the fact that a high number of participants consume large amount of carbohydrates every day. Conclusion: Overall results in this study indicated that this rural community is food insecure, on a higher level during summer and autumn, which leads to the consumption of undiversified diets. The women are malnourished and obese with a risk of metabolic syndrome. The information obtained in this study can be used to formulate strategies to develop interventions that can be used to access sufficient food in rural area in order to improve food insecurity, dietary diversity and, therefore, nutrient adequacy.
The effects of laccase and xanthan gum on the quality of glutten-free amadumbe bread
(2018) Seke, Faith; Kudanga, Tukayi; Amonsou, Eric Oscar
Celiac disease (CD) is an auto-immune disorder that is triggered by the consumption of gluten in predisposed individuals. The only remedy that has been proposed thus far is total exclusion of gluten from the diet. This may be the most difficult task to most celiac disease patients for most of the convenient and widely consumed baked products such as bread are prepared using ingredients that contain gluten. The replacement of gluten in the baking industry comes with some implications on the overall quality of the baked products, especially bread. It has been observed that gluten-free baked products currently on the market are of poor texture, less volume, not visually appealing and have a bad taste. Hence, the need for polymeric substances that can mimic gluten properties, yielding baked products with similar characteristics as the gluten-containing counterparts. Various crops such as rice, sorghum, sweet potato and cassava have been used and additives such as hydrocolloids, protein-based ingredients, emulsifiers and enzymes included to improve gluten-free bread quality. The use of carbohydrate-rich tubers and protein-rich legumes as gluten-free ingredients shows great potential in the food industry. Amadumbe (Colocasia esculenta) is a carbohydrate rich tuber which is highly underutilized in South Africa and contains vast amounts of mucilage, a hydrocolloid which can be of great help to improve dough rheology. Hydrocolloids have been reported in literature to have the ability of improving dough water holding capacity and improving dough viscosity hence facilitating gas retention and impacting on the overall quality of the baked product. However, despite the presence of mucilage, amadumbe is very low in protein and it is difficult to produce bread with properties that resemble gluten-containing bread. Hence the need for protein supplementation which may also potentially facilitate protein cross-linking during bread making. Legume proteins from crops such as soy bean and bambara groundnuts contain abundant quantities of lysine, tyrosine and cysteine which could potentially be manipulated through the use of enzymes such as laccase in order to initiate the formation of a network similar to gluten. The project investigated the effect of laccase and xanthan gum (a hydrocolloid) on the quality of gluten-free bread supplemented with bambara groundnut flour and soy protein isolate as protein sources. Flour blends were prepared using a ratio of 70:30 (amadumbe flour: bambara groundnut flour) and 88:12 (amadumbe flour: soy protein isolate) based on a targeted protein content of 16 g/100 g and the quality properties were determined. Colour analysis showed that amadumbe flour had a higher L* value compared to the other flours and the blends, showing that amadumbe can be used in applications where food colour contributes to food perceptions. However, when bambara groundnut flour and soy protein isolate were added the L* value decreased. The nutritional profile of the individual flours and the blends showed that amadumbe flour protein content was improved with the addition of bambara groundnut flour and soy protein isolate in the above-mentioned ratios. The protein content of amadumbe increased from 2.36 g/100 g to 15.87 g when bambara groundnut flour was added and to 16.10 g/100 g when soy protein isolate was added, values that were close to the targeted protein content. Incorporating bambara groundnut flour and soy protein isolate in amadumbe flour resulted in improved water absorption capacity, foam capacity and stability as well as emulsion capacity and stability of the amadumbe flour. However, there was no significant difference in oil absorption capacity between amadumbe flour and the blends. The blends were then used to formulate different bread samples incorporating the enzyme laccase (25 nkat/g flour) and a hydrocolloid, xanthan gum (1%). Laccase-mediated treatment of gluten-free amadumbe dough resulted in a 30% decrease in the free sulfhydryl groups and a 40% decrease in phenolic content indicating that crosslinking had occurred. Laccase action resulted in a 64% increase in bread specific volume and a 32% decrease in bread crumb hardness. Sensory analysis showed that laccase-treated bread samples were more acceptable compared to the non-treated bread samples in terms of appearance, texture, aroma and taste. The acceptability index varied between 46% and 86.2%. This study showed that there is great potential of laccase in gluten-free bread making. The addition of 1% xanthan gum to amadumbe dough supplemented with bambara groundnut flour and soy protein isolate resulted in gluten-free amadumbe bread with improved crumb texture and specific volume, and decreased the rate of moisture loss. Sensory analysis also revealed that gluten-free amadumbe bread with added xanthan gum was more acceptable compared to the bread samples without xanthan gum. The acceptability index of the bread samples ranged between 40% and 85%. The resulting bread with xanthan gum showed that hydrocolloids such as xanthan gum can be successfully used in the development of gluten-free baked products. Overall, this study has shown that the incorporation of laccase and xanthan gum to gluten-free amadumbe bread results in bread with improved and acceptable bread properties.
Electrochemical aptasensor for the detection of mycotoxins in food samples by experimental and computational methods
(2021) Kunene, Kwanele; Bisetty, Krishna; Kanchi, Suvardhan; Sabela, Myalowenkosi Innocent
Mycotoxins are secondary metabolites of fungi that are present in various foodstuff and feed commodities. A large number of mycotoxins exist, however only a limited number represent a major damages and toxic properties. Amongst them, the aflatoxins and ochratoxins are deemed to be the most poisonous and extensively circulated in the world and then, represent a real hazard to both human and animal. Depending on several factors like the consumption levels, exposure time, mechanisms of action, digestion and defense mechanisms, mycotoxins stimulate a wide spectrum of toxicological effects leading to both acute and chronic diseases, liver and kidney failure, skin rash, cancer, immune suppression, birth defects or even death. To address the harmful impact of mycotoxin contaminants in food and feed, health authorities in various countries world-wide have established guidelines in order to protect human and animal from the possible damages instigated by these toxins. Authorities such as the European Commission, US Food and Drug Administration (FDA), World Health Organization (WHO) and the Food and Agriculture Organization of the United Nations (FAO) set up maximum level regulations for main mycotoxins in foods and feeds. To accomplish the expectations of these regulation levels, there is a great need for the development and validation of modern, uncomplicated, rapid, and detailed methodologies for the detection of toxins. In this study, various approaches for the rapid, inexpensive and ultrasensitive biosensors for the detection of two major mycotoxins were developed. The electrochemical-based aptasensor and immunosensor were developed for the determination of aflatoxin B1 (AFB1) and ochratoxin A (OTA) in different food products. The fabricated biosensors demonstrated good practical analytical feasibility for mycotoxins detection in real samples such as WeetBix, yoghurt, coffee and in wine samples with excellent recoveries and RSD values. To avoid fouling on the sensor surface by the constituents present in real samples, the carbon screen printed electrode (C-SPE) and carbon felt electrode (CFE) surfaces were modified with different nanomaterials such as silver nanoparticle (AgNPs), palladium nanoparticles (PdNPs), palladium doped boron nitride (PdNPs-BN) and titanium nanoparticles doped with boron nitride BN-TiO2. In addition, the aptamers and antibodies were immobilized on the modified electrode in order to enhance the selectivity of the sensor towards the detection of OTA and AFB1. The electrochemical aptasensor for OTA permitted for highly sensitive detection in Weet-Bix with a wide linear range (0.002 - 0.016 mg L-1) and limit of detection of 7×10-4 mg L-1. It is worth prominence that it is the first time that carbon screen printed electrode (C-SPE) modified with AgNPs was used, opening new pathways for highly precise analysis. Experimental results were further supported computationally for a better understanding of the interaction between the aptamer and the analytes. Computational results were in good agreement with experimental results. The same procedure was also established in voltammetric detection of AFB1 using CFE modified with BN-TiO2 (CF/BN-TiO2). A wide concentration range of 2.5 - 20 ng mL-1 with an excellent LOD of 0.002 ng mL-1 for AFB1 was obtained. For the case study of wine samples tested for AFB1 detection, a simple but very effective pretreatment method was effectively applied. The addition of acetonitrile to the wine reduces the non-specific interactions that might be accountable for inactivation of antibody and blocking of the sensor surface. Furthermore, the PdNPs-BN enhanced the electrical signal and the sensor sensitivity. Attained results allowed for AFB1 detection at concentrations range from 1.0 - 10 ng mL-1 with limit of detection of 0.832 ng mL-1 . In the case study of the electrochemical immunosensor for the detection of OTA in coffee, a linear detection range of 0.5 - 20 ng mL-1 was achieved with LOD of 0.096 ng mL-1 . The fabricated aptasensors and immunosensors in this study combines the most desirable characteristics of a good biosensor such as high sensitivity, inexpensive, rapid, and simple but portable method make proposed approaches an important and very promising tools for extensive biosensing applications.
Energy and daylighting performances of highly glazed buildings
(Building Simulation, 2015-12) Singh, Ramkishore; Lazarus, Ian Joseph
Glazed façades create indoor environment more attractive and pleasant but also let high solar and thermal gains in the buildings that lead to energy inefficiency. Hence, more attention needs to be given to the glazed component to improve the buildings’ energy performance and indoor visual comfort. This study aims to provide insightful on the suitable selection of the glazed components for the office buildings. In this study, a number of simulations were performed, using EnergyPlus, for the office rooms with one and two exposure wall(s) in two different climates. Results were analysed and presented in terms of the energy demands for heating, cooling, fans and lightings and daylighting performance considering useful daylight illuminance (UDI) and discomfort glare.
Evaluation of biohydrogen production potential of sugarcane bagasse using activated sludge in a dark fermentation process
(2016) Reddy, Karen; Bux, Faizal; Kuttun Pillai, Sheena Kumari; Gupta, Sanjay Kumar
Anaerobic dark fermentation is an efficient biological process to produce hydrogen from waste material. In South Africa, this technology has not been explored adequately to extract energy from biological wastes. Within the KwaZulu Natal region of South Africa, the sugar industry is a prominent venture that produces mass quantities of sugarcane bagasse amongst other waste products. This by-product can be an ideal source of substrate for biohydrogen generation. In this study, sugarcane bagasse was used as the main substrate for biohydrogen production by anaerobic fermentation using sewage sludge as the inoculum. Different pre-treatment methods were employed to maximize the release of fermentable sugars from the lignocellulosic biomass. Among the different pre-treatment methods employed, the maximum sugar yield (294.4 mg/g) was achieved with 0.25% H2SO4 for 60 minutes at 121°C. Prior to inoculation, the sewage sludge was also subjected to thermal pre-treatment to eliminate methanogens. Thermal pre-treatment of inoculum sludge for 30 min was effective in eliminating methanogens. Fluorescence in situ hybridization was used to positively identify the hydrogen producing bacteria present before and after treatment. The pre-treated substrate and inoculum was integrated into a dark fermentation process to further optimize the effect of pH, substrate to biomass, iron and magnetite nanoparticles on hydrogen production. The maximum hydrogen production (1.2 mol/mol glucose) was achieved at a pH range of 5-6, a substrate to biomass ratio of 3.5, and iron and magnetite nanoparticle concentration of 200 mg/L. Microbial analysis using quantitative polymerase chain reaction has confirmed the dominance of Clostridium spp. in the reactor. The highest hydrogenase gene activity (number of copies of hydrogenase gene expression/ng DNA) was recorded in the reactor supplemented with magnetite nanoparticles with lowest being in the raw sludge. There was a direct positive correlation between the hydrogenase gene copy number and the hydrogen yield obtained at different reactor conditions. Scanning electron microscopy was a useful to visually analyse the interaction of microorganisms with activated sludge. This study highlights the significance of anaerobic microorganisms from waste sludge being able to utilize agricultural waste material to produce biohydrogen which could be further scaled up for continuous hydrogen production. In addition, statistical tools used to predict the possible sugar (Design of experiments) and hydrogen yields (Gompertz model) produced would be helpful in saving time during full-scale operation of biohydrogen producing reactors.
Evaluation of chitosan–coated magnetic nanoparticle-immobilized thermostable hemicellulases for enhanced saccharification and production of bioethanol
(2022-09) Mdlaka, Sibongile Patience; Singh, Suren; Puri, Adarsh Kumar
Enhancing the efficiency of saccharification of pentose and hexose sugars present in lignocellulosic biomass is a major bottleneck for industrial bioethanol production. This problem can be addressed by a concerted effort combining nanotechnology, enzymology and fermentation technology. Functionalized chitosan-coated magnetic nanoparticles (CCMNPs) were prepared and used for co-immobilization of purified xylan hydrolysing xylanase and xylosidase from the thermophilic fungus Thermomyces lanuginosus SSBP for the release of xylose. Stability studies revealed that immobilized enzymes were more stable than free enzymes over a wide range of pH (4.0 – 7.0) and temperature (40 – 90 °C) for xylanase and 30 – 80 °C for xylosidase. The optimum activity of the co-immobilized enzymes shifted slightly as compared to the free enzymes, with coimmobilized xylanase and xylosidase showing optimum activity at pH 6.5 and 6.0, respectively. The study showed sustained production of xylose as the major fermentable sugar under repeated batch and fed-batch saccharification of lignocellulosic biomass. Statistical optimization of saccharification of 1% xylan using response surface methodology indicated the enhanced release of xylose at 50 °C, pH 7.0 and enzyme dose of 60 U/mL xylanase and 30 U/mL xylosidase. Finally, liberated xylose was fermented with Scheffersomyces stipitis to yield bioethanol.
Evaluation of toxicity and biochemical characterisation of a microalgal diatom
(2023-05) Beekrum, Lamees; Amonsou, Eric Oscar; Odhav, Bharti; Lalloo, Raj
One ofthe critical challengesthat we face in the 21st century isthe need to feed an ever-increasing human population with increasingly limited natural resources. Microalgae have emerged as a potentialsolution for global food security as a sustainable biological food source for humans due to their nutrient-rich composition, particularly rich protein and bioactive compoundsthat provide potential benefits for human health. By establishing microalgae as a new food platform, we can increase the supply of these essential productsto address global demandsin a more efficient and environmentally sustainable way. These under-exploited organisms have been consumed in the human diet for thousands of years. Microalgae cultivation does not compete with land and resources required for traditional crops and has a superior yield compared to terrestrial crops. Diatoms are a major group of microalgae in the phytoplankton community and have the potential to be engineered into cell factoriesforthe sustainable production of bioactive compoundsin food and nutraceutical industries. This study aimed to characterise a rapidly growing marine diatom in terms of its toxicity and biochemical profile. This was done by evaluating the safety profile and biochemical composition, characterising the soluble protein, and investigating the carbohydrate profile with specific emphasis of β-glucan and its effect of cardioprotective properties on ferric-induced oxidative cardiac injury in a rat model. Based on Basic Local Alignment Search Tool (BLAST) analysis, the strain showed the closest similarity to Amphora sp. (JF834543.1) with 99.5% and istherefore represented as Amphora sp., accession number MW721231. The bacterial reverse mutation assay found no evidence of mutagenicity on the methanolic, aqueous, and hexane extracts of Amphora sp. and was found to exert low levels of cytotoxicity against Peripheral Blood Mononuclear Cells (PBMC). A 28- day acute oral toxicity assessment on male Wistar rats showed an absence of adverse effects and mortality in the rats. The biomass exhibited a low lipid profile, modest protein content, notable amino acid content, and excellent carbohydrate and mineral content. Results of this study for antioxidant assays displayed low to moderate activities. Protein extracted using three-phase partitioning (TPP) treatment showed that the protein concentration and total amino acid content were substantially higher in the protein-enriched biomass extract when compared to the dried biomass. The solubility of the protein-enriched biomass extract increased with the increase in pH within the range of pH 2 to pH 12. The biomass consisted of a simple monosaccharide profile comprising glucose, rhamnose, and mannose, and a β-glucan content of approximately 9%. The cardioprotective properties ofthe β-glucan extract on ferric-induced oxidative cardiac injury did not improve the glutathione (GSH) level significantly, it led to increased superoxide dismutase (SOD) and catalase activities, while depleting malondialdehyde (MDA), NO (nitric oxide), low-density lipoprotein cholesterol levels, and simultaneously elevating triglycerides and high-density lipoprotein (LDL) cholesterol levels. GC-MS analysis revealed a complete depletion of the lipid metabolites. Our results advocate the protective capabilities of the β-glucan extract against ferric-induced oxidative cardiac injury as portrayed by its ability to stall oxidative stress and modulate cardiac lipid metabolism while inhibiting the acetylcholinesterase and lipase activities. These results display that the β-glucan extract could be utilized as an alternative for the development of nutraceuticals for maintaining cardiac health. The diversity of food bioactive molecules obtained from microalgae makes these microorganisms a bioresource with full potential of exploitation in the food industry. The richness of compounds in microalgae can contribute to develop an algal-based food industry, focusing on producing and utilizing microalgae for innovative functional food products. Overall, this study demonstrated the potential utilization of the diatom, Amphora sp. as a potential ingredient and nutraceutical in foods.
Fishing and fish consumption contributing to the nutrient profile, dietary diversity and food security of adult caregivers in a coastal community in Rivers State, southern Nigeria
(2019-06) Legbara, Kadi Prudence; Napier, Carin E.; Hart, A.
Introduction: The contribution of fishing practices and fish consumption to food and nutrition security cannot be over emphasized, particularly where large numbers of people are poor. Nutrition research has identified fish and fishery products as key components of human nutrition as well as one of the essential foods to incorporate into daily dietary food consumption based on its potential health benefits. These benefits have promoted the consumption of fish in recent times. Fish contains proteins, vitamins and fats (Omega 3 Polyunsaturated Fatty Acids) (PUFAs) among other nutrients (Domingo 2016: 979). Recently, there has been a notable increase in the harvesting of wild stocks of fish and shellfish. Oceans are currently at their maximum sustainable yields to cope with the world’s growing population and the demand for fish and shellfish. Overexploitation and the use of harmful chemicals used in harvesting fish and oil exploitation are some of the core reasons for the global decline of fish. These factors pose a threat to the ecological health of marine resources (Bennette and Dearden 2014: 107) and the economy of low-income countries whose livelihood largely depends on fishing for household and national food security sources (Sowman and Cardoso 2010: 1164). In the research community of Buguma, the decline of the fish population is attributed to the corrosion of pipelines, sabotage and mishandling of oil production operations. The petroleum and gas/oil products from this mismanagement find access directly into the rivers and creeks. The residue from these substances settles on the ocean floor, endangering the ecosystem by killing marine life such as fish and seafood. To this end, food and nutrition insecurity have become evident in the community as livelihoods are dependent on fishing and fish is a primary source of protein. Food insecurity is further aggravated by the high rate of unemployment and low educational attainment. The households are left to apply certain strategies to cope with household food shortfalls. Having to employ certain strategies to cope with food insecurity, negatively affects nutrient adequacy. Thus, inadequate nutrient intake and imbalances have resulted in poor health outcomes and malnutrition. Aim: The study aim was to determine the fishing practices and fish consumption contributing to the nutrient profile, dietary diversity and food security of adult caregivers in a coastal community. Methodology: Two hundred and forty-seven respondents were selected using a multi-stage sampling method. The sample size was calculated using a power calculation indicating that 250 respondents represents a reliable sample out of which 247 respondents completed the research instruments. Sampling procedures were multistage (cluster and random) sampling. The study was descriptive and quantitative in nature. Research tools used to collect data were a sociodemographic questionnaire, a fishing practices questionnaire, a coping strategies questionnaire, a food frequency questionnaire, 3x24-hour dietary recall questionnaires and an anthropometric measurement questionnaire. Food frequency and food security coping strategies questionnaires were compiled through focus group discussions to establish the relevant foods consumed and the respondents were interviewed for the socio-demographic, food frequency, food security coping strategies and fishing practices data. All the respondents were also weighed and measured in order to determine Body Mass Index (BMI), Waist Circumference (WC), Waist to Height Ratio (WHtR) and Blood Pressure (BP) classified in terms of World Health Organization (WHO) reference cut-off points. Socio-demographics, fishing practices, coping strategies and food frequency data were captured on Excel spread sheets and analyzed for descriptive statistics using the Statistical Package for Social Science (SPSS) version 24.0. Data from the 24-hour recall was captured and analyzed for nutrient analysis using the MRC Food Finder® version 3.0 software and comparisons were made to the recommended nutrient standards by the World Health Organization. Results: The mean age group was 31-50 years old. Sixty-one-point one percent (n=151) of the respondents were females and males made up 38.9% (n=96). Most of the fish caught by the respondents was used for consumption (64.0%; n=126) and the rest was used for income generation (36.0%; n=71). The community had on average a secondary school education (55.5%; n=137) and recorded high rates of unemployment (80.2%; n=198) with 62.3% (n=76) actively looking for employment. The respondents indicated that between one person (47.8%; n=118) and two people (46.2%; n=114) contributed to household income. Thirty-three-point two percent (n=82) had an average income of #21,000 to #30,000 (Rand value: R3100-R4000), while 25.5% had a monthly income of #31,000 to #40,000 (Rand value: R4100-R5000), accommodating six persons (42.1%; n=104) and four persons (22.3%; n=55) in the household. Thirty-seven-point seven percent (n=93) and 25.5% (n=63) respectively complained that the household “sometimes” and “always” had insufficient funds to buy food. This had led households to adopt certain coping strategies to combat food shortages. The most frequently used strategies per mean were: “relying on less expensive or preferred foods” (11.47 ±7.949), “limiting portion size” (9.73 ±2.593) and “restricting consumption by adults in order for children to eat” (8.70 ±6.628). The negative effect of applying these coping strategies adversely compromised nutrient adequacy. The 20 top consumed foods showed consumption of more energy dense foods and less fruits and vegetables. The Food Variety Score (FVS) indicated that 51 different individual food items with mean ±SD of 20.83. (±6.546) from all food groups were consumed. Vitamin K, Biotin, pantothenate, calcium, riboflavin and thiamine were below DRIs recommendation cutting across all age groups and genders. Inappropriate imbalances in food intake reflected in BMI, WC and WHtR. The mean BMI for men (25.07kg/m2) and women (27.66kg/m2) fells into the overweight category with a mean average of 26.36kg/m2 for both genders and age groups while only women (95.46cm) were majorly found to be at risk for an elevated WC/ central obesity per mean average. The WHtR at risk factor affected the female gender (88.70%; n=133, 19-50 years and 88.90%; n=18, 51+ years old) compared to their male (44.4%; n=78, 19-50 years and 61.1%; n=18, 51+years) counterparts. Mean high BP for systolic (146.9mmHg) and diastolic (92.2mmHg) BP occurred in women 51+ years old. Conclusion: This research revealed inappropriate eating patterns and increased risk of developing NCDs. The 20 top foods consumed showed consumption of mostly macronutrients and limited consumption of fruits and vegetables across both genders and all age groups. Overweight, at risk for WC and WHtR and High Blood Pressure (HBP) were an indication of the presence of NCDs. Food insecurity resulting from a jeopardized fishing livelihood, high levels of unemployment and low educational attainment were the main causes of a compromised nutritional status in the research community. The introduction of nutrition education and an alternative means of livelihood will assist in addressing the current food and nutrition insecurity.