Research Articles (Food Science)

Permanent URI for this collectionhttp://hdl.handle.net/2263/1727

This collection contains some of the full text peer-reviewed/ refereed articles published by researchers from the Department of Food Science

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Systematic review of the agro-ecological, nutritional, and medicinal properties of the neglected and underutilized plant species Tylosema fassoglense
(MDPI, 2024-07) Munialo, Sussy; Gasparatos, Alexandros; Ludidi, Ndiko; Ali, Ali Elnaeim Elbasheir; Keyster, Eden; Akanbi, Musa Oyebowale; Emmambux, Mohammad Naushad; sussy.munialo@up.ac.za
Neglected and Under-utilized plant Species (NUS) can contribute to food system transformation in Sub-Saharan Africa, but many are understudied. Here, we conducted a systematic review of 37 empirical studies to synthesize the evidence from Sub-Saharan Africa about the agro-ecological characteristics, nutritional properties, and medicinal properties of the NUS Tylosema fassoglense. Overall, the evidence is highly fragmented and lacks a comprehensive description of the species characteristics, properties, and benefits. Most reviewed studies focus on the eastern part of Africa and a few on the southern part, suggesting its limited geographic distribution. Studies on agro-ecological properties, and especially on morphological characteristics, indicate that the species’ long tuberous roots and large vegetative systems help it adapt to harsh climatic conditions. The species is also utilized for medicinal and nutrition purposes by different communities across its range due to its phytochemical, macro-, and micronutrient content, along with its favorable physico-chemical properties. In particular, the seeds contain many different amino acids, while their calcium, magnesium, phosphorus, zinc, and carbohydrate content is comparable to Tylosema esculuntum, the better studied species in the Tylosema genus. These demonstrate the species’ potential to contribute to nutrition and food security. Furthermore, parts of the plant contain many phytochemicals, such as phenolics, alkaloids, flavonoid, terpenoids, and tannins (mainly in the roots), and for this reason local communities use it to treat various conditions. Overall, our systematic review suggests that although Tylosema fassoglense has some potential to contribute towards food security, nutrition, health, and livelihoods, there are many remaining knowledge gaps that constrain its effective integration into agricultural production systems and possible contribution to food system transformation in the region.
Unpacking consumer preferences : perceptions and sustainability of packaging material for orange juice
(MDPI, 2024-07) Dlamini, Nomzamo N.; Mayhew, Emily J.; Nolden, Alissa A.
Understanding the motivation behind consumers’ packaging choices is crucial to providing insights for achieving environmental sustainability outcomes. Here, we examined the influence of product attributes (packaging type, packaging claim, product claim, and price) and consumers factors (e.g., diet type, demographic information) driving orange juice selection. Participants residing in the USA (n = 847) responded to an online survey including: (1) a check-all-that-apply (CATA) to valued beverage characteristics question; (2) a choice-based conjoint task with packaging type, packaging claim, product claim, and price as the attributes; (3) a question tasking respondents to rank packaging material from their perception of the least to most sustainable; and (4) demographic questions. The conjoint analysis revealed that price was the most important attribute, particularly the lowest price. This study revealed that the most ideal orange juice option was packaged in glass, labelled as 100% recyclable, locally produced, and priced at $1.10 per 12 fl. oz. Not only was glass the most preferred packaging type, but it was also incorrectly perceived as the most sustainable. The intention to purchase sustainable packaging was the most important predictor of attribute relative importance (RI) and packaging utilities, followed by effectiveness perception, which only predicted the RI of price. Thus, for consumers to make more sustainable choices, education initiatives need to direct consumers to more sustainable, yet affordable, choices, while considering that purchase intention and effectiveness perception are key attitudinal drivers.
Low β-carotene bioaccessibility and bioavailability from high fat, dairy-based meal
(Springer, 2024-09) Kruger, Johanita; Sus, Nadine; Moser, Andrea; Scholz, Sophie; Adler, Guenther; Venturelli, Sascha; Frank, Jan
PURPOSE : The original aim of the study was to determine, in a double-blind 3-arm crossover human trial (n = 7), the effect of supplemental levels of iron (25 mg) and zinc (30 mg) on β-carotene (synthetic) bioavailability (10 h postprandial). However, despite the high dose of supplemental β-carotene (15 mg) consumed with the high fat (18 g), dairy-based breakfast test meal, there was a negligible postprandial response in plasma and triglyceride rich fraction β-carotene concentrations. We then systematically investigated the possible reasons for this low bioavailability of β-carotene. METHODS : We determined (1) if the supplemental β-carotene could be micellised and absorbed by epithelial cells, using a Caco-2 cell model, (2) if the fat from the test meal was sufficiently bioavailable to facilitate β-carotene bioavailability, (3) the extent to which the β-carotene could have been metabolised and converted to retinoic acid/retinol and (4) the effect of the test meal matrix on the β-carotene bioaccessibility (in vitro digestion) and Caco-2 cellular uptake. RESULTS : We found that (1) The supplemental β-carotene could be micellised and absorbed by epithelial cells, (2) the postprandial plasma triacylglycerol response was substantial (approximately 75–100 mg dL−1 over 10 h), indicating sufficient lipid bioavailability to ensure β-carotene absorption, (3) the high fat content of the meal (approximately 18 g) could have resulted in increased β-carotene metabolism, (4) β-carotene bioaccessibility from the dairy-based test meal was sixfold lower (p < 0.05) than when digested with olive oil. CONCLUSION : The low β-carotene bioavailability is probably due to a combination of the metabolism of β-carotene to retinol by BCMO1 and interactions of β-carotene with the food matrix, decreasing the bioaccessibility. TRAIL REGISTRATION : The human trail was retrospectively registered (ClinicalTrail.gov ID: NCT05840848).
The development, psychometric properties and refinement of a food literacy scale for specific and general application
(Elsevier, 2024-03) Fisher, Hennie; Potgieter, Marietjie; hennie.fisher@up.ac.za
Please read abstract in the article.
Recent developments in the application of natural pigments as pH-sensitive food freshness indicators in biopolymer-based smart packaging : challenges and opportunities
(Wiley, 2024-04) Ndwandwe, Bongekile K.; Malinga, Soraya P.; Kayitesi, Eugenie; Dlamini, Bhekisisa C.
Recently, the assimilation of pH-sensitive natural pigments into biopolymers has shown promising prospects for pH-reactive based smart packaging material. Unlike synthetic pigments, which have potential safety problems due to migration, natural pigments have negligible toxicity levels both to humans and the environment and some even possess nutritional and pharmacological properties. To complement the advantages of natural pigments, natural biopolymers have proven to be ideal candidates for the development of smart packaging because of their biocompatibility, availability, biodegradability, stability, minimum toxicity and good film-forming capability. Smart packaging gives consumers real-time signals on the quality of packaged food via food deterioration indicators like pH alteration. This review will consider the recent progress in the development of pH-responsive smart packaging based on natural pH-sensitive pigments and natural biopolymers from 2013 to the present. It will further discuss the challenges and opportunities of colorimetric smart packaging.
Diarrhoeagenic Escherichia coli and Salmonella spp. contamination of food and water consumed by children with diarrhoea in Maputo, Mozambique
(MDPI, 2024-09) Faife, Sara; Macuamule, Custódia; Gichure, Josphat Njenga; Hald, Tine; Buys, Elna; elna.buys@up.ac.za
In Mozambique, about 500,000 cases of diarrhoea were caused by foodborne pathogens in 2018. A review of the epidemiology of diarrhoea in children under five showed a high disease burden. This study aimed to identify Diarrhoeagenic Escherichia coli (DEC) and Salmonella spp. contamination of food and water in urban and rural areas of Maputo consumed by children under five with diarrhoea. One hundred and eighty-six children with diarrhoea were selected from Primeiro de Maio and Marracuene Health Care Centres from the Kamaxakeni and Marracuene districts, respectively. Food (n = 167) and water (n = 100) samples were collected in children’s households for diarrhoeagenic bacterial identification. Interviews were conducted using a semi-structured questionnaire to collect data about demographics and foods consumed a week before the children’s diarrhoea episodes. The prevalence of both DEC and Salmonella spp. was 9.8% in food and 5.4% in water samples. DEC was most prevalent in cereals (urban = 2.8%; rural = 2.4%) and water samples (urban = 1.4%; rural = 3.3%). Salmonella spp. was mainly detected in cereals (urban = 0.7%; rural = 0.8%). Diarrhoeagenic pathogens were associated with the type of food frequently consumed by children under five years with diarrhoea (infant formula, fruit puree, ready-to-eat meals, and bottled water), while the association with demographics was absent. We found that the infant foods consumed by children with diarrhoea are associated with DEC and Salmonella spp., and the prevalence of these contaminants is higher in the rural (8.9%) than in the urban area (6.3%), showing the need for caregiver education on food handling practices.
All we crave is pleasure! The motivation behind millennial men's clothing store choices when purchasing semi-formal/smart workwear for themselves
(Wiley, 2024-07) Diedericks, Lizette; Erasmus, Alet C. (Aletta Catharina); Donoghue, Sune; erasmusa@gibs.co.za
Multi-method research was conducted in South Africa to explore the personal values that shape millennial men's clothing retail store choices when purchasing semi-formal/smart workwear for themselves. The qualitative phase comprised in-depth, personal interviews with 25 participants, implementing soft laddering to elicit the preferred attributes and desired consequences that drive clothing retail store choices. These ‘easier to communicate’ properties formed the crux of the phase 2 measuring instrument. The online quantitative questionnaire, an interactive version of the established Association Pattern Technique (APT), was completed by 408 millennial men as part of the means-end chain (MEC) procedure. The stepwise process produced a series of hierarchical value maps (HVMs), disclosing two prominent underlying personal values that drive millennial men's clothing store choices. ‘Pleasure’ emerged as the most prominent personal value, signalling millennials' high regard for enjoyable shopping experiences. The importance of a sense of ‘security’ should also be noted. Accordingly, the underlying forces that drive this financially lucrative cohort's clothing retail store choices extend beyond the marketing principles taught in business schools. Retailers will, therefore, have to delve deeper to understand their target markets' needs to prosper in a highly competitive marketplace.
Tourists’ luxury value and sustainability perceptions of South African exotic leather products
(Academic Conferences International Limited, 2024-03) Sonnenberg, Nadine Cynthia; Labuschagne, Marlien; De Klerk, Helena Maria; nadine.sonnenberg@up.ac.za
Travelling mostly involves expenditure on products beyond daily consumables (i.e. tourism shopping), but sometimes tourists visit a country with the specific intention of acquiring goods unique to that particular context, either for personal or commercial use. This type of “shopping tourism” contributes to the growth of luxury markets such as the exotic leather industry. In stimulating shopping tourism and promoting the local exotic leather industry, it is crucial to understand tourists’ underlying perceptions and sustainable values that influence their luxury shopping behaviour. Using animal skins to create fashion accessories involves several environmental concerns and remains controversial among American and Chinese consumers, who rank among the world’s top luxury goods spenders. This research, therefore, investigated American and Chinese shopping tourists’ luxury value perceptions, sustainability excellence perceptions, and purchase intent for South African exotic leather products. Data was derived from a purposive sample including both American and Chinese tourists, aged 25 years and older, who had either visited South Africa in the past or intended to visit the country soon. A structured online questionnaire consisting of scales adapted from prior empirical research was developed. The English version of the questionnaire was translated into Mandarin and Cantonese for Chinese tourists. Data analysis involved two structural equation models (one based on the American and another on the Chinese tourists’ responses) to test hierarchical relationships among variables. The results confirm that personal luxury value strongly influences sustainability excellence and the purchase intent of exotic leather products for both American and Chinese respondents. These findings highlight the potential of positioning South Africa as a luxury shopping tourism destination for exotic leather products, thus contributing toward economic growth and employment opportunities. However, environmental concerns must be addressed to conform to Eastern and Western tourists' sustainable luxury value perceptions.
The microbial genetic diversity and succession associated with processing waters at different broiler processing stages in an abattoir in Australia
(MDPI, 2023-03-20) Gichure, Josphat Njenga; Coorey, Ranil; Njage, Patrick Murigu Kamau; Dykes, Gary A.; Muema, Esther K.; Buys, E.M. (Elna Maria); esther.muema@fabi.up.ac.za
The high organic content of abattoir-associated process water provides an alternative for low-cost and non-invasive sample collection. This study investigated the association of microbial diversity from an abattoir processing environment with that of chicken meat. Water samples from scalders, defeathering, evisceration, carcass-washer, chillers, and post-chill carcass rinsate were collected from a large-scale abattoir in Australia. DNA was extracted using theWizard® Genomic DNA Purification Kit, and the 16S rRNA v3-v4 gene region was sequenced using Illumina MiSeq. The results revealed that the Firmicutes decreased from scalding to evisceration (72.55%) and increased with chilling (23.47%), with the Proteobacteria and Bacteroidota changing inversely. A diverse bacterial community with 24 phyla and 392 genera was recovered from the post-chill chicken, with Anoxybacillus (71.84%), Megamonas (4.18%), Gallibacterium (2.14%), Unclassified Lachnospiraceae (1.87%), and Lactobacillus (1.80%) being the abundant genera. The alpha diversity increased from scalding to chilling, while the beta diversity revealed a significant separation of clusters at different processing points (p = 0.01). The alpha- and beta-diversity revealed significant contamination during the defeathering, with a redistribution of the bacteria during the chilling. This study concluded that the genetic diversity during the defeathering is strongly associated with the extent of the post-chill contamination, and may be used to indicate the microbial quality of the chicken meat.
Systematic review of the literature to inform the development of a South African dietary polyphenol composition database
(MDPI, 2023-05) Jumat, Malory; Duodu, Kwaku Gyebi; Van Graan, Averalda; gyebi.duodu@up.ac.za
Comprehensively compiled dietary polyphenol data is required to compare polyphenol content between foods, calculate polyphenol intake and study its association with health and disease. The purpose of this review was to identify data on the presence and content of polyphenolic components in South African foods, with the aim of compiling the data into a database. An electronic literature search was conducted up until January 2020 using multiple databases. Additional literature was sourced from South African university repositories. A total of 7051 potentially eligible references were identified, of which 384 met the inclusion criteria. These studies provided information on food item name, geographical distribution, polyphenol type, quantity, and quantification method. Data for 1070 foods were identified, amounting to 4994 polyphenols. Spectrophotometry was the main method used for quantification of gross phenolic content in various assays such as total phenolic content (Folin–Ciocalteu assay), total flavonoid content (AlCl3 assay) and condensed tannin content (vanillin–HCl assay). Phenolic acids and flavonoids were the main polyphenol classes identified. This review highlights that South Africa has abundant information on the polyphenol content of foods, which could be utilised within a food composition database for the estimation of polyphenol intake for South Africa.
Comparison of feeding practices and growth of urbanized African infants aged 6–12 months old by maternal HIV status in Gauteng Province, South Africa
(MDPI, 2023-03-21) Tshiambara, Phumudzo; Hoffman, Marinel; Legodi, Heather; Botha, Tanita; Mulol, Helen; Pisa, Pedro Terrence; Feucht, Ute Dagmar; phumudzo.mamphwe@up.ac.za
Appropriate feeding practices are protective against malnutrition and poor growth. We compared feeding practices and growth in HIV-exposed-uninfected (HEU) and HIV-unexposeduninfected (HUU) between 6-12 months of age in urbanized African infants in South Africa. A repeated cross-sectional analysis was used to determine differences in infant feeding practices and anthropometric measures by HIV exposure status at 6, 9, and 12 months in the Siyakhula study. The study included 181 infants (86 HEU; 95 HUU). Breastfeeding rates were lower in HEU vs. HUU infants at 9 (35.6% vs. 57.3%; p = 0.013) and 12 months (24.7% vs. 48.0%; p = 0.005). Introduction to early complementary foods was common (HEU = 16.2 11.0 vs. HUU = 12.8 9.3 weeks; p = 0.118). Lower weight-for-age Z-scores (WAZ) and head circumference-for-age Z-scores (HCZ) were found in HEU infants at birth. At 6 months,WAZ, length-for-age Z-scores (LAZ), HCZ, and mid-upper-arm circumference-for-age Z-scores (MUACAZ) were lower in HEU vs. HUU infants. At 9 months, lowerWAZ, LAZ, and MUACAZ were found in HEU vs. HUU infants. At 12 months, lowerWAZ, MUACAZ, and weight-for-length Z-scores (0.2 1.2 vs. 0.2 1.2; p = 0.020) were observed. HEU infants had lower rates of breastfeeding and poorer growth compared to HUU infants. Maternal HIV exposure affects the feeding practices and growth of infants.
South African consumers’ knowledge, opinions and awareness of whole grains and their health benefits : a cross-sectional online survey
(MDPI, 2023-08-10) Taylor, John R.N.; Rehm, Colin D.; De Kock, Henrietta Letitia; Donoghue, Sune; Johnson, Andrew; Thompson, Chanelle; Berezhnaya, Yulia; john.taylor@up.ac.za
Evidence indicates that whole-grain food consumption reduces the risk of cardiovascular disease, type-2 diabetes, and some cancers. Increasing whole-grain consumption in developing countries is likely to significantly benefit the health of the population. However, there is very limited information on consumer whole-grain knowledge, attitudes, and behaviors in developing countries. An online cross-sectional survey was conducted among 1000 South African consumers with sufficient income to make food purchase choices and who were generally representative in terms of gender, age, and ethnicity. Most respondents (64%) were confident of their whole-grain knowledge. However, 60% of all participants selected incorrect definitions of whole grains. Whilst most correctly identified common cereals as whole grains, at most 50% of participants correctly identified common whole-grain foods. Also, whilst most (67%) thought that they were consuming enough whole grains, the majority (62%) underestimated the recommended level of consumption. Furthermore, respondent knowledge regarding whole-grain food attributes and the health benefits of whole-grain consumption was generally poor. Clearly, consumer-focused strategies are needed in developing countries to increase whole-grain food consumption to help the broader population achieve a healthy and sustainable diet. Actions proposed include: simple-to-understand information on whole-grain content relative to recommendations on food product labels, the provision of whole-grain foods in school nutrition schemes, and coordinated social and behavior change communication initiatives.
Chronic cassava meal modulates body weight, histology and weight of reproductive organs in male albino rats
(Springer, 2023-09) Egbune, Olisemeke U.; Egbune, Egoamaka O.; Orororo, Osuvwe C.; Ezedom, Theresa; Onojakpor, Ogheneyoma Suzan; Sabo, Ahmed M.; Amadi, Kemakolam
OBJECTIVE : This study evaluated the effect of chronic cassava meals on some reproductive parameters of male albino rats. METHODS : Twenty-four sexually mature albino rats were divided into four groups which received oral treatments from a variety of cassava products containing cyanogenic glycosides in varying quantities: Group A—Control (received 300 g normal rat feeds); Group B (received 50 g red garri at a concentration of 150 ppm cyanogenic glycosides/rat/day); Group C (received 50 g white garri at a concentration of 200 ppm cyanogenic glycosides/rat/day); and Group D (received 50 g raw cassava at a concentration of 400 ppm cyanogenic glycosides/rat/day). After 60 days of treatment, male reproductive organs were harvested from the rats for histological examination. Also noted were the weights of the body and the organs. RESULTS : The weight of the body and reproductive organs significantly changed in group D after receiving raw cassava at a dose of 400 ppm/rat/day. Compared to the group treated with red garri at 100 ppm/rat/day cyanogenic glycosides, which showed no significant changes in body weight gain or the weight of the reproductive organs, the white garri group showed substantial changes in the testis and prostate weight. The group given 150 ppm/rat/day of red garri did not exhibit any changes in histology, but the groups given 150 ppm/rat/day of white garri and 400 ppm/rat/day of raw cassava displayed testicular atrophy, degeneration, vacuolation, decreased secretion, and desquamation of glandular epithelium in the prostate. CONCLUSIONS : This study has revealed that the concentration of cyanogenic glycosides is higher in raw cassava and white garri than red garri, and that 400 ppm/day of cyanogenic glycosides may have negative impacts on their ability to reproduce.
Functional properties and in vitro starch digestibility of infrared-treated (micronized) green banana flour
(Wiley, 2023-07) Khoza, Minenhle; Kayitesi, Eugenie; Dlamini, Bhekisisa C.
BACKGROUND : The consumption of green banana flour (GBF) products has been linked to reduced glycemic index (GI) and low risk of type 2 diabetes and obesity. The purpose of this study was to investigate the effect of micronization (high-intensity infrared heating method) on the molecular, microstructure and in vitro starch digestibility of five GBF cultivars grown in South Africa. The GBF was micronized at three surface temperatures (90, 120 and 150 °C for 30 min) and the in vitro starch digestibility was determined with Megazyme kits. RESULTS : Micronization at the highest temperature (150 °C) increased the swelling power by 6.00% in all five GBF cultivars when compared to control (unmicronized GBF). Micronization slightly reduced the resistant starch (RS) of the GBF cultivars by up to 8.63%. The FHIA-01 cultivar showed the highest RS (86.50%), whereas Grande Naine – 150 °C cultivar had the lowest RS (76.00%). Both micronized and control GBF exhibited similar X-ray diffraction patterns with all cultivars and at all micronization temperatures. Similarly, the functional properties of the GBF were not altered by micronization when observed with Fourier transform infrared spectroscopy. Scanning electron microscopy showed changes in the surface morphology of starch granules after micronization and these were dependent on temperature. CONCLUSION : Overall, micronization at 120 °C showed the best improvement in functional properties of GBF and this makes it suitable for potential application for the manufacture of instant breakfast products, baked goods and pasta. In addition, the micronized GBF cultivars retained high RS, suggesting potential health benefits for people with diabetes and obesity.
“I find it hard to change poor food habits” : measuring food choice motives in an emerging economy
(Elsevier, 2024-09) Dlamini, Nomzamo N.; Ramkilawon, Gopika Devi; Tuorila, Hely; De Kock, Henrietta Letitia; u13034929@tuks.co.za
Food choices are driven by an array of motives that have been approached, determined and quantified in a number of ways, mainly in developed countries. The objective of this study was to better understand the motives behind food choices in an emerging economy by collecting information from urban people in South Africa in a series of four studies. (1) Items generated through focus group discussions with low, middle and high income participants by Magano et al. (2023) were checked for content and face validity and (2) 123 statements derived from them were evaluated by 621 respondents. After exploratory factor analysis (EFA), 46 statements best representing the motivational space were (3) presented to another group of respondents (n = 259). Here, the EFA resulted in a 31-item, 7-factor food choice questionnaire for emerging economies (FCQ-EE) which was (4) confirmed by a nationwide sample (n = 814) and further refined to an alternative 19-item, 7-factor solution. The emerging factors were: Healthy eating constraints (HEC), Frugality (FR), Emotional eating (EE), Meat appeal (MA), Weather (WE), Quality seeking (QS) and Cooking constraints (CC). Whether used in the 31-item or 19-item format, this set of statements highlights factors underlying food choice in an emerging economy and offers a way to study their importance in similar contexts. Further research is needed to show the extent to which these factors can predict actual food choices.
University-industry-government research and development collaborations in public higher education institutions in South Africa
(NISC (Pty) Ltd and Informa UK Limited (trading as Taylor & Francis Group), 2023) Sihlobo, Sinqobile; Mbatha, Sipho
This paper explores the university, industry and government (UIG) research and development (R&D) collaborations that academia in South African higher education institutions (HEIs) with clothing-related programmes engage in. In the research on which the paper is based, Fashion, Consumer Science, Textiles and Clothing Management academia were purposively sampled to gather data regarding the UIG R&D collaborations. Data collection was conducted through an online questionnaire. Descriptive statistics were employed to analyze data and present results in figures and graphs. Findings show that majority surveyed academia had never been involved in UIG R&D collaborations with any government levels, the clothing, textiles, leather and footwear (CTLF) industry or other clothing related organizations. The paper concludes that the ability of surveyed academia to produce ‘relevant’ new knowledge may be limited due to under developed UIG R&D collaborations. The likelihood of the surveyed clothing-related programmes producing graduates with ‘relevant skills’ for a changing world may also be negatively impacted.
Etiology-specific incidence and mortality of diarrheal diseases in the African region : a systematic review and meta-analysis
(BMC, 2024-07) Thystrup, Cecilie; Majowicz, Shannon E.; Kitila, Dinaol B.; Desta, Binyam N.; Fayemi, Olanrewaju E.; Ayolabi, Christianah I.; Hugho, Ephrasia; Buys, E.M. (Elna Maria); Akanni, Gabriel B.; Machava, Norgia E.; Monjane, Celso; Hald, Tine; Pires, Sara M.
BACKGROUND : Diarrheal diseases substantially affect public health impact in low- and middle-income countries (LMIC), particularly in Africa, where previous studies have indicated a lack of comprehensive data. With a growing number of primary studies on enteric infections in Africa, this study aimed to estimate the incidence and mortality of diarrheal pathogens across all ages in Africa in the year 2020. We also explored different methodological assumptions to allow comparison with other approaches. METHODS : Through a systematic review and meta-analysis of data from African LMICs, we estimated the etiology proportions for diarrheal diseases and deaths. We combined the etiology proportions with incidence data collected from a population survey in Africa from 2020 and mortality data from the Global Health Observatory of WHO. RESULTS : We estimated 1,008 billion diarrhea cases (95% UI 447 million-1,4 billion) and 515,031 diarrhea deaths (95% UI 248,983-1,007,641) in the African region in 2020. In children under five, enteroaggregative E. coli (EAEC) (44,073 cases per 100,000 people, 95% UI 18,818 − 60,922) and G. lamblia (36,116 cases per 100,000 people, 95% UI 15,245 − 49,961) were the leading causes of illness. Enteroinvasive E. coli (EIEC) (155 deaths per 100,000 people, 95% UI 106.5-252.9) and rotavirus (61.5 deaths per 100,000 people, 95% UI 42.3-100.3) were the primary causes of deaths. For children over five and adults, Salmonella spp. caused the largest number of diarrheal cases in the population of children ≥ 5 and adults (122,090 cases per 100,000 people, 95% UI 51,833 − 168,822), while rotavirus (16.4 deaths per 100,000 people, 95% UI 4.2–36.7) and enteroaggregative E. coli (EAEC) (14.6 deaths per 100,000 people, 95% UI 3.9–32.9) causing the most deaths. Geographically, the highest incidence of diarrhea was in Eastern Africa for children under five (114,389 cases per 100,000 people, 95% UI 34,771 − 172,884) and Central Africa for children over five and adults (117,820 cases per 100,000 people, 95% UI 75,111–157,584). Diarrheal mortality was highest in Western Africa for both children below five and above (children < 5: 194.5 deaths per 100,000 people, 95% UI 120-325.4; children ≥ 5 and above: 33.5 deaths per 100,000 people, 95% UI 12.9–75.1). CONCLUSION : These findings provide new information on the incidence and mortality of sixteen pathogens and highlight the need for surveillance and control of diarrheal infectious diseases in Africa. The cause-specific estimates are crucial for prioritizing diarrheal disease prevention in the region.
Development and characterization of poly(butylene succinate-co-adipate)/poly(3-hydroxybutyrate-co-3-hydroxyvalerate) with colignocellulosic fibers as a filler via injection molding and extrusion film-casting
(Wiley, 2024-08) Masanabo, Mondli Abednicko; Tribot, Amelie; Luoma, Enni; Virkajarvi, Jussi; Sharmin, Nusrat; Sivertsvik, Morten; Ray, Suprakas Sinha; Keranen, Janne; Emmambux, Mohammad Naushad; naushad.emmambux@up.ac.za
Biodegradable poly(butylene succinate-co-adipate)/Poly(3-hydroxybutyrate-co-3-hydoxyvalerate) (PBSA/PHBV) filled with lignocellulosic sidestream/fibers from cowpea, a neglected and underutilized African crop are produced by injection molding and extrusion film casting. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) suggests that the fibers have more affinity and interfacial interaction with PBSA than PHBV. This is shown by a decrease in dampening of PBSA and an increase in dampening of PHBV with fiber addition. In addition, fiber addition results in more homogeneous crystal morphology of PBSA, while resulting in more heterogeneous crystal morphology of PHBV. The tensile strength of injection molded bio-composites increases with fiber addition due to good interfacial adhesion between the matrix and fibers revealed by scanning electron microscope. In contrast, the tensile strength of bio-composite films decreases with fiber addition due to the high-volume fraction of pores in bio-composite films that act as stress raisers. The stiffness of both injection molded, and bio-composite films increase with fiber addition, as revealed by an increase in Young's modulus and storage modulus, while the tensile strain decreases. In conclusion, low-value cowpea sidestream can be used as a filler to produce injection molded bio-composites and bio-composite films for potential application as rigid and flexible packaging.
Effects of sourdough-type fermentation and sorghum type on the techno-functional properties of the batter used for kisra, a fermented flatbread
(Elsevier, 2024-07) Ali, Sami Sidahmed; Taylor, J.R.N. (John Reginald Nuttall); Emmambux, Mohammad Naushad; naushad.emmambux@up.ac.za
Techno-functional properties of six sorghum types were determined during spontaneous sourdough batter-type fermentation for Kisra production. All sorghum types showed a progressive decrease in pH to about 3.3 with fermentation for 40 h, accompanied by an increase in titratable acidity and free amino nitrogen. Fermentation increased pasting viscosity at 16 and 24 h, but decreased at 40 h due to starch hydrolysis. Protein hydrolysis as shown by SDS-PAGE leads to disaggregation of flour particles and the release of starch granules to increase the pasting viscosity. Thus, starch was more freely available to absorb water to paste and produce a higher viscosity from zero to 40 h. The decrease in pasting viscosity from 24 h to 40 h of fermentation was related to starch hydrolysis, as there was a reduction in total starch in the batter and pitting of starch granules, as shown by scanning electron microscopy. Fermentation had a more significant effect on techno-functional properties than sorghum types. Low protein and high tannin contents among the sorghum type also showed higher pasting viscosity. The techno-functional changes of sorghum batter during fermentation, especially the high pasting viscosity, might be helpful for structure design of kisra and other gluten-free sorghum-based products.
Effects of combining microwave with infrared energy on the drying kinetics and technofunctional properties of orange-fleshed sweet potato
(Wiley, 2024-05) Kgonothi, Daddy; Mehlomakulu, Ngwekazi Nwabisa; Emmambux, Mohammad Naushad; naushad.emmambux@up.ac.za
The aim of the study was to determine the effects of oven, microwave (MW), and infrared (IR) drying technology on the drying kinetics, physicochemical properties, and β-carotene retention of the dried orange-fleshed sweet potato flour (OFSP). Fresh OFSP slices were dried in an oven (40°C), MW (80 W), IR (250 W), MW-IR (80 W + 250 W), and freeze-drying (-45°C, 100 kPa) and milled into flour. Hot air at a constant temperature was applied to all thermal drying technologies (40°C, 4.5 m/s air velocity). The drying rate of the MW-IR drying method was the fastest (45 min), followed by MW (60 min), IR (120 min), and oven (180 min). The Page model was most suitable for the oven-drying method, the Lewis model for IR drying, and Henderson and Pabis for IR and Logarithmic for the MW-IR method. The pasting and thermal properties of the flours were not significantly (p > 0.05) affected by the different drying methods. However, IR- and MW-IR-dried flours showed a higher final viscosity when compared to other drying methods. MW-IR drying methods, IR, and MW showed a higher water solubility index, while the oven and freeze-drying methods showed a lower solubility index. MW-IR drying methods showed a higher retention of β-carotene (85.06%). MW also showed a higher retention of β-carotene (80.46%), followed by IR (66.04%), while oven and freeze-drying methods showed a lower retention of β-carotene. High β-carotene retention in the produced flour is due to the faster drying method, and these flours can be used in food-to-food fortification to address vitamin A deficiency.

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