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Start date: 2023Subject: search.filters.subject.Plant bioactive compounds

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    The consumption, product compliance and manufacturer insights of plant-based foods in KwaZulu-Natal
    (2024-09) Govender, Camilla; Naicker, Ashika; Makanjana, Onwaba
    Background: The term plant-based diet focuses predominantly on the consumption of food from plants. A plant-based diet consists mainly of wholegrains, fruits, vegetables, legumes, nuts, seeds and may also include more processed food products made from these ingredients. Food is the single most powerful lever to optimise human health and environmental sustainability. A large body of work has emerged on the environmental impact of various diets. As per the findings of the Environmental Assessment and Reference Tool (EAT)-Lancet Commission, many studies have concluded that a diet rich in plant-based foods (PBFs) has improved health and also environmental benefits. This transition has led to a noteworthy increase in the demand for PBFs globally, and South Africa is no exception. Aim: This study aimed to determine the consumption, product compliance and manufacturer insights of plant-based foods in KwaZulu-Natal (KZN). Methods: This study used a mixed methods approach, namely, qualitative and quantitative research methodology. The first objective of this study was to determine the consumption of PBFs and identify barriers and facilitators influencing the adoption of plant-based diets through a consumer survey. The study's second objective was to document the scope of plant-based products in terms of availability through in-store and online observations that were available in KZN. All products were analysed to determine the scientific and regulatory compliance of plant-based products by analysing food labels according to the Foodstuffs, Cosmetic and Disinfectant Act (Act 54, 1972), R146 Regulation relating to the labelling and advertising of foodstuffs. The qualitative aspect of the study delved into the product development practices, trends and challenges of plant-based manufacturers in South Africa through key informant interviews. The adequacy of the diet among consumers (n=100) who consumed plant-based foods was assessed through two 24-hour food recalls and analysed for dietary adequacy. Results: Three hundred and eighty consumers participated in the online survey, of which 67.7% (n=259) of participants were women and 31.3% (n=120). Regarding the frequency of consumption of PBFs, 47% (n=180) of participants consumed PBFs between 2 to 3 times a week, 27.7% (n=106) of participants consumed PBFs daily, 17.2% (n=66) of participants consumed PBFs once a week, and 4.2% (n=16) of participants consumed PBFs once a month. A significant 63.4% (n=243) of participants indicated that they spend at most R60.00 on plantbased products, p<0.001. Using the binomial test to assess if any response option was selected significantly more than others, a significant number of participants (80% n=307) p<0.001, reported that they consumed PBFs for health reasons, followed by 37% (n=142) who reported that they consumed PBFs due to religious reasons. A significant 64% (n=245) and 58.5% (n=224) of participants reported that the most common format of plant-based meat alternatives that they consumed were burgers and sausages, respectively (p<0.001). The findings of this study also revealed that there are many challenges and barriers that are associated with the adoption of PBFs. This study found that 58.5% of participants (n=224) reported that PBFs were expensive (p<0.001), and 40.5% of participants (n=155) indicated that PBFs were limited and lacked variety. A comprehensive database of plant-based products (n=431) in the South African market was documented through in-store and online observations. Eighty-nine percent (n=386) of the products documented were manufactured in South Africa.. Regarding South Africa's labelling regulation, 95% (n=411) of the plant-based products complied with legislation. Key informant interviews were conducted with manufacturers to understand the market trends and constraints within the South African plant-based food sector. Key themes emerging from the key informant interviews included consumer-centric PBFs, consumer-driven plant-based trends, growth in the plant-based market, dynamic and evolving plant-based product development, challenges in PBF manufacture and marketability, insufficient government support and market-related price of PBFs. Furthermore, the adequacy of plant-based diets was analysed using the 24-hour food recall (n=92). The majority of nutrients fell below the EAR for both males and females. Both groups exhibited dietary inadequacies in specific micronutrients: vitamin D, folate, vitamin B12, and iron. Dietary inadequacy of specific micronutrients was noted for vitamin D, Folate, vitamin B12 and iron in both groups. However, there was notable carbohydrate excess intake across both groups and genders, surpassing the recommended estimate for energy. Conclusion: This study comprehensively examined the consumption patterns, product compliance, and manufacturer insights of PBFs in KZN. The findings reveal a growing interest in flexitarian diets and frequent consumption of PBFs, driven primarily by health motivations but hindered by cost and limited variety. Retail availability of PBFs in KZN is extensive, offering consumers a wide range of choices in both fresh and frozen categories, reflecting the robust state of the plant-based industry in KZN and it can be reasonably generalised to the whole country Regulatory compliance among PBFs is generally high, although small-scale manufacturers occasionally fall short of labelling standards. Manufacturer insights indicate a consumer-driven demand for PBFs that closely mimic meat products, necessitating innovation and regulatory support to stabilise this emerging market. Nutritional assessments of plant-based diets highlight a critical need for dietary supplementation to address deficiencies in essential vitamins and minerals such as B12, iron, and zinc. The study underscores the importance of nutrition education to guide consumers towards healthier food choices within plant-based diets. In conclusion, while the plant-based food sector in KZN is expanding and meeting many consumer needs, there are significant opportunities for improvement in product variety, affordability, regulatory compliance, and nutritional adequacy. Addressing these challenges through coordinated efforts among stakeholders can further enhance the adoption and benefits of plant-based diets. The conclusions drawn from this study can be reasonably generalised to metropolitan areas of the whole country.
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    Antioxidant and anticancer properties of bioactive peptides from Lablab purpureus
    (2023-05) Sipahli, Shivon; Mellem, John Jason
    Cancer can be described as a non-communicable disease that develops from defective cells in the human body and grows uncontrollably. Globally in 2020, statistics revealed that the disease had affected approximately 19.3 million people. With about 51% of these cases resulting in death. Cancer treatments usually comprise surgery, chemotherapy, radiotherapy, or a combination of the three. Traditional therapies such as chemotherapy and radiotherapy drugs are effective at shrinking tumours. However, a key disadvantage is that these drugs are unable to distinguish between cancerous and healthy cells. Subsequently, the human body experiences many adverse side effects such as hair loss, vomiting, lowered immunity, and a general deterioration of health. Drug resistance and rejection are also major disadvantages of these traditional therapies. Alternative therapies are required to mitigate these drawbacks. The vital factor to consider for alternative treatments should be to selectively target cancer cells thereby alleviating the unwanted side effects. Compounds derived from non-toxic edible plants have shown to have bioactive potential. These plants are regarded as non-toxic to the human body therefore they would be able to target the tumour cells alone. Plant compounds also provide additional protection such as their antioxidant abilities and apoptotic potential. Evidence suggests that bioactive peptides derived from legumes can act as both anticancer agents and strong antioxidants. This study investigated the bioactive potential of peptides derived from Lablab purpureus. This investigation began by assessing the antioxidant capacity (2,2-diphenyl-1-picrylhydrazyl-hydrate (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic (ABTS), superoxide radical scavenging and Ferric Reducing Antioxidant Power (FRAP) assays) and antiproliferative abilities (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT)) of L. purpureus protein isolate and hydrolysates (alcalase, trypsin and pepsin). The hydrolysate and fractions of interest were selected based on the MTT assay with the pepsin hydrolysate selected for further apoptotic studies (caspase-3 and -7, and annexin V-PI). Thereafter, the pepsin hydrolysate was fractionated by ultrafiltration (molecular weight cut-off: <1, 3, 5, 10, >10 kDa). The 3 kDa fraction was further fractionated by RP-HPLC. Five peaks appeared on the chromatogram, however, fraction 2 was selected, for apoptotic investigations (caspase -3 and -9, p53 and annexin V-PI). Antioxidant studies are a good measure of the isolate or hydrolysate's ability to perform as a bioactive compound. The 50% inhibitory concentration (IC50) observed for the respective antioxidant studies showed the radical scavenging ability of the isolate and hydrolysates to be 1.81-4.47 mg/mL (DPPH), 1.73-2.42 mg/mL (ABTS), 1.36-4.4 mg/mL (superoxide radical scavenging) and 19.20-21.94 mg/mL (FRAP). Anticancer activity was substantiated by the peptides' ability to induce apoptosis. The pepsin hydrolysate was selected using the MTT assay (IC50 values of A549, 119.6; MCF7, 9.80 and HEK293, 13.86 µg/mL). Pepsin hydrolysate inhibited cancerous cells (A549 and MCF-7) while causing minimal damage to healthy cells (HEK293). Thereafter apoptotic markers, caspase 3/7 and annexin V-PI were quantified. Visualisation of cells in different stages of apoptosis was investigated by Annexin V-PI staining quantified by flow cytometry. During early apoptosis; A549, 42%; MCF-7, 17%; HEK293, 34%. Caspase 3/7 assay verified that the pepsin hydrolysate caused an increase in apoptotic activity. Caspase-3 and -9 activity of cells, determined by ELISA showed that Fraction 2 treated cancer cells (A549 - 0.067 ng/mL, 21.966 ng/mL, and MCF-7 - 0.137 ng/mL, 0.205 ng/mL respectively) had a greater caspase concentration over camptothecin (A549 - 0.029 ng/mL, 20.486 ng/mL and MCF-7 - 0.051 ng/mL, 0.112 ng/mL respectively). Tumour suppressor protein, p53, acts as a protective mechanism by initiating apoptosis in ‘suspicious’ cells. The A549 cell line showed the greatest p53 expression compared to MCF-7 and HEK293. Increased p53 can regulate signalling pathways leading to targeted apoptosis. Finally, annexin V-PI confirmed that Fraction 2 did induce apoptosis in the cells (cells in early apoptosis, A549, 85%; MCF-7, 90%; HEK293, 94%). Results from this study have shown that peptides derived from L. purpureus (specifically fraction 2) have potential anticancer abilities which may be attributed to their antioxidant and apoptotic abilities.