Papers by Beulah Pretorius
Introduction: Diets lack diversity, and the consumption of a few energy-dense cash crops is incre... more Introduction: Diets lack diversity, and the consumption of a few energy-dense cash crops is increasing. Nguni goats are an underutilised, indigenous source of red meat in sub-Saharan Africa. They survive in semi-arid and arid areas with little to no agricultural input. The nutritional contribution of Nguni goat meat is not well researched and documented from a food and nutrition security perspective. Objective: To determine the composition of Nguni goat meat, in comparison with other red meat species in the South African diet, focusing on the fatty acid profile. Method: The nutritional analyses, including the proximate analysis, minerals, and the fatty acid profile of Nguni goat meat from three different regions in South Africa, was performed and compared with other red meat species in the diet. Results: Values reported for moisture (74.2 g/100 g), ash (1.02 g/100 g) and protein (19.5%) are similar to other sources of red meat, with the total fat content (4.4%) being slightly lower. Nguni goat meat is a good source of iron (2.89 mg/100 g) and zinc (4.02 mg/100 g). Furthermore, the values reported for saturated fatty acids (2.55 g/100 g), monounsaturated fatty acids (1.51 g/100 g), polyunsaturated fatty acids (0.36 g/100 g) and cholesterol (5 mg/100 g) content of indigenous goat meat were lower than other red meat species. However, the percentage of saturated fatty acids (57.7%) and monounsaturated fatty acids (34.2%) to total fat is similar to other red meat sources but higher for polyunsaturated fatty acids (8.14%). Stearic acid (C18:0) (1.10 g/100 g) is the most prevalent saturated fatty acid, elaidic acid (C18:1t9) (0.11 g/100 g) is the most prevalent monounsaturated fatty acid and linoleic acid (C18:22 n6) (0.23 g/100 g) is the most prevalent polyunsaturated fatty acid. The omega-3 fatty acids and omega-6 fatty acids content is 0.07% and 0.25%, respectively. The majority of the PUFA's is linoleic acid (C18:22 n6) and is similar to values reported for beef. Conclusions: Goat meat is a nutritious underutilised indigenous, food source that can contribute toward increasing dietary diversity, thereby improving nutrition and food security in sub-Saharan Africa.
Chemical and Physical Characterization of 'Egusi' Seeds and Prediction of Fat Content by Nir Spectroscopy
Journal of Nutritional Health & Food Engineering, May 4, 2017
"Slap chips" are a traditionally South Africa product that is widely consumed throughout the coun... more "Slap chips" are a traditionally South Africa product that is widely consumed throughout the country. These chips are similar to French fries but are thicker and fried for a longer time at a lower temperature using a double fry method. It is assumed that different textural properties of potatoes will lead to certain cultivars being better suited for deep fat frying than others. As part of this study, a market investigation was conducted to better understand slap chip preparation methods so as to develop a repeatable slap chip preparation method that simulates market conditions. Chips prepared using this method were evaluated by a trained sensory panel to determine sensory attributes of aroma, appearance, flavour, texture and aftertaste. A standardised cooking method for slap chips preparation was developed. Statistical analyses showed that waxy and oily attributes grouped cultivars together, while dry matter, fried chip and earthy flavours differentiated between chips from different cultivars. No obvious grouping for cultivars within the same class according to the current South African potato classification system was found. It can be concluded that deep fat frying has such a significant impact on the chip characteristics that cultivar specific attributes have a lesser impact on the final characteristics of the product. However certain attributes such as dry matter can have an impact on the oil absorption of tubers.
Examining the contribution of an underutilized food source, Bambara Groundnut, in improving protein intake in Sub-Saharan Africa
Frontiers in Sustainable Food Systems
IntroductionBambara groundnut (BGN) is an underutilised, indigenous crop in sub-Saharan Africa. A... more IntroductionBambara groundnut (BGN) is an underutilised, indigenous crop in sub-Saharan Africa. As an underutilised crop the nutritional contribution it can make is not well researched and documented. This study aims to better understand the nutritional profile and protein quality of BGN and the potential of this legume to combat food and nutritional security in rural and malnourished communities.MethodsNutritional analysis, including proximate analysis, minerals, total fat and amino acid profile of BGN from three different regions in the Mpumalanga (MP) province of South Africa (SA), were determined. The protein quality was evaluated with various methods including CSEAA, IEAA, PDCAAS and DIAAS and compared with other pulses and legumes in the diet.ResultsBGN consists of - 18,9% carbohydrates, 9,4% protein and 3% fat as consumed. The protein quality is lower than some other commonly consumed pulses but can still be valuable as a complementary protein in the current traditional diet ...
Frontiers in Sustainable Food Systems
High-quality food composition data are indispensable for improved decision-making in food securit... more High-quality food composition data are indispensable for improved decision-making in food security, health policy formulation, food labeling, diet formulation, agricultural policymaking, nutrition research, and many other nutrition-related activities. The optimisation of dietary patterns is a powerful tool to reduce the impact of malnutrition on a population’s health and well-being. Many countries in resource-poor settings lack a framework for developing and managing food composition data appropriate for these purposes. In the article, an overview of available food composition tables in Africa and the origin, use and limitations of theses tables are discussed. It is important that those working on any nutrition-related activity for resource-poor settings understand the limitations of current food composition data. Production of high-quality data requires the harmonization and adoption of international standards and guidelines across Africa. Moreover, continuity in the production, co...
Investigating consumer perceptions towards red meat classification
Compare your dairy options : processing
The quality of nutrition depends on the distribution of nutrients and their availability in the f... more The quality of nutrition depends on the distribution of nutrients and their availability in the food and water consumed.
Lipid Technology, 2016
Regular consumption of red meat is often considered detrimental to human health due, among other ... more Regular consumption of red meat is often considered detrimental to human health due, among other factors, to a perceived unhealthy fatty acid profile. With production systems intensifying globally, grain-fed beef from feedlots are dominating market shelves within westernized countries. Although grass fed beef is considered to be a healthier alternative due to a lower total fat content and more desirable fatty acid composition, no studies have been performed to quantify such differences in South Africa. The current study evaluated the fatty acid profile of the different beef offerings available on the market, and expressed the data per edible portion to effectively guide future dietary recommendations. Notable differences were found in the quantity and quality of different fatty acids between the different production systems. Due to the unique classification system dictating the characteristics of fresh meat the result indicated distinctive differences between South African red meat and international produce.
Antinutrients and metabolomic compounds of Bambara groundnut (Vigna subterranean) as affected by traditional processing by smallholder farmers
Journal of Food Science
Bambara groundnut (BG) (Vigna subterranean) is an underutilized, indigenous crop in South Africa ... more Bambara groundnut (BG) (Vigna subterranean) is an underutilized, indigenous crop in South Africa that has nutritional and associated health benefits. Decreasing the antinutrients in food sources can potentially increase the digestibility of proteins and mineral absorption. To determine the effect of traditional processing (cooking) on the antinutrient content and metabolome of this crop, BG was sampled from 12 rural farms in three districts of the Mpumalanga province, South Africa. The four main colors that were identified (cream, orange, brown, and purple) were pooled together according to the district they were obtained from. One‐half of each color sample obtained from each of the three districts was dehulled, color sorted, milled, and subjected to subsequent antinutrient and metabolome analyses, while the other half was cooked, air‐dried, and milled prior to analyses. Samples were analyzed for phytate and tannins (antinutrients) by hydrochloric acid extraction methods as well as ...
Opportunities for higher education institutions to develop sustainable food systems in Africa
Frontiers in Sustainable Food Systems
An African Vice-Chancellors' Regional Food Systems Dialogue was hosted with the aim to provid... more An African Vice-Chancellors' Regional Food Systems Dialogue was hosted with the aim to provide a multi-stakeholder platform for stakeholders to explore various existing and emerging approaches that have the potential to deliver sustainable solutions at scale and encourage collaborative actions to directly transform Africa's agriculture and food systems. Various food system experts and leaders from policy research institutions, universities, and other stakeholders participated. A lack of coherent linkages among stakeholders, youth restlessness, and silos within and between higher education institutions were some of the challenges identified to hindering the much needed transformation. Poor links with ministries and political red tape, inadequate programme funding and capital for coping with rising input costs, as well as unsustainable resource mobilization were also reported as having a negative effect. To address these, stakeholders must embrace collaboration and transdiscip...
Evaluating the Effect of External Conditions on the Quality Attributes of Potatoes
Potato Research
What’s cooking? Exploring red meat cooking methods among consumers in the Western Cape
Plaas Media, Jun 1, 2020
Protein Quality of South African Potatoes to Inform Dietary Choices
Potato Research, 2022
Cholesterol, fatty acids profile and the indices of atherogenicity and thrombogenicity of raw lamb and mutton offal
Food Chemistry, 2021
Dietary fats may affect blood lipid levels and the development of cardiovascular diseases. Offal,... more Dietary fats may affect blood lipid levels and the development of cardiovascular diseases. Offal, may contribute to food security in marginalised communities and information on the contribution to dietary fat intake is needed to inform dietary guidelines and recommendations and consumers. This study aimed to describe the fatty acid profile, cholesterol content and indexes of lipid quality. The fatty acid profile and cholesterol were determined by gas chromatography coupled with flame ionisation detection (GC-FID). To evaluate lipid quality the indices of atherogenicity (IA) and thrombogenicity (IT) were calculated. Offal products can contribute beneficial fatty acids to the diet, not only in terms of essential fatty acids such as linoleic (C18:2n-6) and alpha linolenic (C18:3n-3) acids, but also the polyunsaturated fatty acids, arachidonic (C20:4n-6) and eicosapentaenoic (C20:5n3) acids. The offal studied in the present work showed a P/S ratio of 0.04-0.12 and the n-6/n-3 ratio varied between 3.9 and 12.5.
Contemporary policy issues and the imperatives to reduce malnutrition
Food Security Policy, Evaluation and Impact Assessment, 2019
Sustainability, 2021
Poor diets are responsible for more of the global burden of disease than sex, drugs, alcohol, and... more Poor diets are responsible for more of the global burden of disease than sex, drugs, alcohol, and tobacco combined. Without good health, food security, and nutrition, development is unsustainable. How food is grown, distributed, processed, marketed, and sold determines which foods are available, affordable, and acceptable within the local cultural context. These factors guide food choices, influencing the quality of people’s diets, and hence they play a vital part in health. The food system is complex and is neither nutrition nor health driven. Good nutrition and human health are not seen as important supply chain outcomes, diminishing between the different processes and actors in the chain. This is in contrast to the environmental and labour concerns now also perceived as supply chain issues. Although food loss and waste is now appreciated as key to sustainable food supply chains, the critical role on nutrition security remains obscure. In a free market dispensation, the trade-offs...
So much more than just a bean
Red meat often evokes a wide array of complex and contradictory arguments. It is viewed as the mo... more Red meat often evokes a wide array of complex and contradictory arguments. It is viewed as the most expensive component of any diet, supplying many essential nutrients as part of a healthy, prudent eating plan. Yet, red meat is non-homogenous, unique to each country, and continually changing in composition. It is observed that the amount of fat on carcasses has reduced over time, simultaneously improving nutrient density through feed efficiency. The objective of this paper is to present composition data on South African lamb, mutton and beef, and report on the changes observed between local data and international data (for lamb and mutton), as well as changes in the composition of South African beef over time. South African lamb and mutton contain notably less fat and more nutrients per 100 g product than international sheep meat produced, rendering a lean product with a higher nutrient density. Compared to previous studies on South African beef, the current data indicate notable ch...
A preliminary study on mycotoxin contamination in red meat from registered abattoirs in South Africa
Mycotoxin Research, 2021
The frequency of some major mycotoxins in marker tissues (liver and kidney) and in muscle tissue ... more The frequency of some major mycotoxins in marker tissues (liver and kidney) and in muscle tissue of slaughter pigs and cattle, obtained from registered abattoirs in South Africa, was studied. Samples of each three bovine carcasses were obtained from two abattoirs, and samples of three porcine carcasses were from a third abattoir. All samples originated from animals from subsistence farming. All samples were analysed for aflatoxins (AFB1, AFB2, AFG1, AFG2, deoxynivalenol (DON), ochratoxin A (OTA) and zearalenone (ZEN) using immunoaffinity chromatography extract cleanup and high-performance liquid chromatography (HPLC). At a limit of quantification (LOQ) of 1 μg/kg (individual AFs, 100 μg/kg (DON), 1 μg/kg (OTA) and 20 μg/kg (ZEN)), no mycotoxins were detected in any of the samples.
South African Journal of Animal Science, 1970
The South African consumer market is characterised by socio-economic and cultural diversity. Food... more The South African consumer market is characterised by socio-economic and cultural diversity. Food expenditure patterns, behaviour and preferences differ significantly between the various socio-economic sub-groups. Packaging information, including red meat classification information, could be an important tangible resource used by consumers to gauge product quality. The first objective of the research reported in this paper is to investigate the red meat knowledge, usage and perceptions regarding beef and sheep meat classification and related quality parameters among South African consumers. Consumer perceptions of red meat classification were extracted from a comprehensive consumer survey among stratified representative samples of South African low-, middle- and high-income consumers (n = 165, n = 171 and n = 249). The paper also briefly reports on an in-store ‘observational’ research project that was conducted to develop an understanding of the communication of carcass classificati...
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Papers by Beulah Pretorius