Beulah Pretorius

Effect of different maize meal diets on growth and vitamin A : case-study on chickens

South Africa embarked on mandatory vitamin and mineral fortification of wheat flour and maize meal in 2003 as part of a multi-faceted approach to alleviate malnutrition. However, it was reported, in 2008, that vitamin A deficiency increased despite the mandatory fortification programme. This motivates an investigation into the absorption of vitamin A as fortificant in the maize meal. Relative absorption, in chickens as the biological model, was determined by evaluating growth and vitamin A status. The weight, cumulative feed intake and liver retinol stores of chickens on different diets were measured over a 6week period. The fortified white maize meal diet was able to maintain the vitamin A status of the chickens. Poor absorption of the fortificant vitamin A is therefore not a constraint in combating vitamin A deficiency. It is in therefore also important to focus on the level of fortification delivered when consumed as a traditional prepared dish. In the traditional diet, maize porridge is often consumed with only a relish. The total fat content of the traditional meal is very low, lacking absorption enhancers.

Effect of animal age and trimming practices on the physical composition of Bonsmara beef

Increased economic incentive for producing young and leaner carcasses, as well as demand for lean meat from progressively health conscious consumers, are considered drivers for change in carcass composition over time. Furthermore, many retailers trim visible fat from meat to various degrees and consumers increasingly remove visible fat from meat prior to, or after, cooking. The objective of this study was to determine the composition of South African Bonsmara beef from four age groups from different production systems, as well as to extrapolate the effect of fat trimming on physical composition. Fat content of marketable beef has decreased notably since the 1930s, and beef from the South African Bonsmara breed contains less than 10g lipid per 100g after trimming of subcutaneous fat, irrespective of age. Removal of all visible fat reduces the lipid content to less than 5g per 100g, comparing favourably with other lean animal products.

Total and haem iron content lean meat cuts and the contribution to the diet.

This study provides data on the total and haem iron contents in raw lean beef, chicken, lamb and pork meat samples. Total iron, expressed as mg/100g edible portion on fresh weight basis in raw lean beef (A-age), lamb, pork and chicken average 1.58, 1.64, 0.81 and 0.78, respectively. The haem iron content in beef (A-age), lamb, pork and chicken are 77%, 81%, 88% and 74% respectively of total iron. This has important dietary implications in calculating haem iron fractions of meat as this is higher than the common value used in the Monsen equation.

The nutrient content of selected South African lamb and mutton organ meats (offal)

The Research Technology Fund of the National Research Foundation and Red Meat Research and Development of South Africa.

Bioavailability of Nutrients

Bioavailability aims to describe the effect of metabolic events on nutrient utilization. The supply of nutrients to the human body depends not only on the amount of a nutrient in food but also on its bioavailability. The bioavailability of nutrients is highly variable and can be influenced by numerous factors. Different nutrients (including protein, iron, and vitamin A), and the forms in which they exist in the ingested medium, will react in different ways to inhibitors and enhancers as well as the hosts nutritional status, all of which contribute to nutrient bioavailability.

The important role of food composition in policies and programmes for better public health: A South African case study

Most governments have committed to the set of Sustainable Development Goals established by the United Nations (UN) to be achieved by 2030. Subsequently the governments have drafted, or are in process of drafting, policies and programmes which aim to answer to these global requests. South Africa provides a unique case study: despite economic growth, undernutrition has not improved when compared to other industrialised nations, while at the same time, diet-related non-communicable diseases and obesity have exponentially increased. Access to healthy food is a constitutional right of all South Africans, and towards increasing food security and improving population health, various policies, programmes and regulations have been developed and implemented by the government to rectify the situation. The paper presents an overview of food composition within these public health policies, programmes and regulations and unpacks the important role of accurate food composition data.

The contribution of processed pork meat products to total salt intake in the diet.

Consumption of processed meats is reported to be the second largest contributor to total dietary sodium intake. This study aims to describe the contribution of commonly consumed processed pork products to total salt intake. A large variation was found in the sodium content between similar products. Sodium content (mg/100g) for bacon ranged from 558 to 1570, russians from 762 to 1403, viennas from 480 to 1340 and ham from 696 to 1360 respectively. When converting sodium content from 100g to serving size, different products contributed the most sodium to the diet. A serving size of brawn (125g uncooked) will contribute on average 983mg sodium to total sodium intake. Pork bangers will contribute the lowest amount of sodium (∼400mg) to the diet (∼4% of RDI). Reported daily intake are smaller than indicated serving sizes and the contribution of processed meat to sodium intake can be predicted to be lesser than expected.

Fatty acids in beef from grain- and grass-fed cattle: the unique South African scenario

Abstract Objective: Different fatty acids elicit different responses in the human body once ingested. Although red meat is often considered to be a source of fatty acids which has a negative impact on human health, many studies have reflected variability in the quantity and quality of fatty acids found in red meat produced on different production systems in different countries. This study evaluated the fatty acid profile of beef, produced by the grass- and grain-fed production systems practised in South Africa. Design: Data are reported as a percentage of lipid per 100 g total fat to enable a comparison with international findings. Furthermore, the findings are translated into edible meat portions, taking fat trimming (often associated with red meat intake) into consideration in order to determine the contribution which the different products can make to the human diet. Subjects and setting: Three cuts of beef from cattle from four production groups were sampled and the fatty acid composition analysed for the meat and fat fractions. Results: Notable differences were found in the quantity and quality of different fatty acids in beef from the different production systems. When untrimmed, no statistically significant difference was found in the total fat between beef produced on the different production systems. Differences became more significant as trimming was performed. When trimmed of all visible fat, beef from young cattle fed according to a grain-based feeding system contained less total fat (6.96 g), and less saturated fat (2.16 g) per 100 g, than beef produced from their grass-fed counterparts (9.77 g and 3.30 g, respectively). There was a more favourable omega-6 to omega-3 fatty acid ratio, i.e. 2.0–2.5:1.0 for grass-fed cattle, compared to 8–30:1 for grain-fed cattle, irrespective of the degree of trimming. The beef from the grass-fed cattle also contained a higher quantity of conjugated linoleic acid. Conclusion: A unique classification system for red meat has been implemented in South Africa and dictates the characteristics of the fresh meat that is available to consumers. The results of this study consequently indicate distinctive differences between the fatty acid profile of local red meat and that of beef produce from other countries; often used as a reference for dietary guidance.