Thesis (M.Sc.(Agric.))(Food Science)--University of Pretoria, 2006. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.

Master of Science / Department of Human Nutrition / Kadri Koppel / Products must be tolerant to many conditions, particularly when those products are prepared by consumers. Consumers may not measure added ingredients, they may add or leave out ingredients specified in recipes, or change cooking and holding times for foods. Fortified blended food (FBFs) are used as a source of nutrition for disaster or famine relief in developing countries and sorghum is looked at as a potential alternative to wheat and corn based products that are currently being used as FBFs. Porridge products are the most common dishes prepared from FBFs with a wide range of solids content, cooking times and variations in added ingredients such as sugar and fruit. This study was intended to evaluate the tolerance to preparation variations for a porridge product made as a FBF intended for food aid. Whole Sorghum Soy Blend (WSSB), a fortified, extruded, ground cooked cereal was selected as the FBF for this study. Descriptive sensory analysis was performed to evaluate the tolerance of porridge products made from variations in ingredients and cooking procedures. In this study, most sensory properties were only marginally affected by variations in ingredients or procedures. However, as expected, large differences occurred in some properties such as thickness when solids content varied or sweetness and fruit flavor when fruit was added. Tolerance testing showed that the sensory properties of WSSB had high tolerance to variations in cooking procedures, a positive aspect for product use and development. This means that the product can be modified during preparation by consumers without having a major impact on most sensory properties.

Please read the abstract in the front section of this document / Dissertation (MSc (Food Science))--University of Pretoria, 2007. / Food Science / unrestricted

Sorghum bicolour (L.) Moench is an important staple cereal in Africa, where it ranks second after maize. Despite its importance, the sorghum food industry remains non vibrant, constrained in part by inadequate milling technology. Presently, Prairie Research Laboratory (PRL) type abrasive dehullers and hammer mills, which apparently produce meals of inconsistent quality and low output, are generally used for industrial milling of sorghum. Efforts to improve sorghum milling require an in-depth understanding of how milling process and grain type affect the sensory characteristics of the final food products. Such knowledge is currently lacking. Therefore, this study investigated the effects of milling process and sorghum type on the quality of sorghum meal and porridge. Twelve sorghum types with diverse physico-chemical properties were milled by roller milling (RM), abrasive decortication-hammer milling (ADHM) and hand pounding (HP), and the effects on meal extraction and meal quality were evaluated. Porridges were prepared using standardised Botswana recipe, and their sensory profiles were characterised using Descriptive Sensory Analysis. Additionally, factors that affect the texture of sorghum porridge were investigated, and suggestions for improving the sorghum milling process are given. Both the sorghum type and the milling process affected the quality of the meal and the sensory characteristics of the porridge, but the milling process was found to have more effects on these characteristics than the sorghum type, because of the diverse milling principles of the milling processes. RM gave far better extraction rate and had substantially higher throughput than HP and ADHM. However, meals obtained with RM had slightly more ash and were a little darker, and gave porridges which were correspondingly darker in colour, had slightly more branny aroma, more astringency and bitter taste, than meals obtained with the other two milling processes, indicating higher bran contamination of the meals, presumably caused by fragmentation of the pericarp. Clearly, even with tempering the pericarp was still friable, and hence, requires indepth sorghum tempering studies. Grain hardness proved to be important for milling, as it correlated positively with extraction rate with ADHM and HP, but not with RM. Hard grains generally gave coarser and better refined meals, and produced porridges that were firmer, compared to soft grains. Weathered and pigmented pericarp sorghums produced dark and specky meals, and gave porridges with apparently undesirable sensory qualities, because of staining caused by the pericarp pigments, showing that these characteristics affect the quality of sorghum foods negatively. When used with hard and light coloured sorghums, ADHM gave more appealing meal and porridge qualities (light coloured, firm texture and enhanced cereal aroma), indicating that dry abrasive decortication is advantageous for production of sorghum products with superior sensory qualities. Firmness varied considerably among the porridges, caused by differences in the meal particle sizes, which was predominantly a consequence of the milling process. An increased proportion of coarse endosperm particles, as was the case with HP meals, caused increased porridge firmness. The coarse particles absorbed water slowly, thus restricting swelling of the starch granules, such that a high proportion of non-ruptured gelatinised starch granules that reinforce the porridge matrix resulted. The sorghum type also influenced porridge firmness, whereby the corneous sorghum types with high protein content produced firmer porridges, owing to presence of the hard and less waterpermeable protein-starch matrix in the endosperm meal particles. Because abrasive decortication gave meals and porridges with superior sensory qualities, while roller milling prduced high throughputs, a roller milling system that is preceded by a dry abrasive decortication process is recommended as a versatile milling process for industrial processing of diverse sorghum products that have superior sensory qualities. / Thesis (PhD)--University of Pretoria, 2009. / Food Science / unrestricted

In 2003 the Department of Health of South Africa embarked on a mandatory fortification programme of maize meal as part of the Integrated Nutrition Program (INP) to alleviate malnutrition. The aim of this study was two-fold: firstly, to determine the vitamin A content of South African fortified white maize meal as purchased and the maize porridge as traditionally prepared from it as consumed and secondly, to determine the relative efficacy of the daily consumption of maize meal in sustaining or improving vitamin A status. Maize meal samples for analysis were purchased from various supermarkets and small retail outlets. A High Performance Liquid Chromatograph-Diode Array Detector system with a Reverse Phase C-18 column and isocratic elution was used for separation and quantification of vitamin A. The highest mean vitamin A concentration measured in the maize meal was 261 μgRE/100g and the lowest mean vitamin A concentration was <19 μgRE/100g. Pertaining to the regulations the final minimum level of vitamin A in fortified maize meal must not be less than 187.7 μgRE/100g. The average retention of vitamin A in maize porridge as the difference in vitamin A concentration measured between raw maize meal and cooked porridge was calculated at 39.8%. One of the considerations in a fortification program is the availability of certain micronutrients in the fortified foods, with the focus in this project on vitamin A. An animal model, namely chickens, closely relating the metabolism of vitamin A in humans was used. Chickens are very susceptible to vitamin A deficiencies with similar symptoms. Growth and vitamin A status was evaluated by the weight, feed conversion and liver retinol stores of chickens on five different maize based diets over a six week period. No significant difference in vitamin A levels in the livers of birds on diets with fortified white maize meal, compared to the normal poultry diet consisting of yellow maize meal with added vitamin A was found. It can thus be concluded that the fortificant in the white maize meal is as bioavailable as the vitamin A in the premix used in poultry nutrition. The results of this study show that the vitamin A added as fortificant is absorbed and available to the body. Therefore, fortification of commonly eaten staple foods in the country can significantly improve the vitamin A intake of the population and will improve the overall micronutrient density of their diets. Fortification should be set at levels to include losses incurred through packaging and during transportation, shelf losses and preparation losses. It is also important that the vitamin A content of the product as purchased and consumed must be regularly monitored and regulated by government. Valid and reliable evaluation data are needed to evaluate a program’s success, and to make timeous adjustments for optimal efficiency. / Thesis (PhD)--University of Pretoria, 2011. / Animal and Wildlife Sciences / unrestricted

El presente proyecto tiene como tema de estudio la instalación de una planta elaboradora de mazamorra de maracuyá a base de almidón de arracacha lista para consumir. El producto tiene una presentación en frascos de vidrio personales de 180 gramos, el cual se comercializará en supermercados, bodegas y autoservicios. El mercado meta está determinado por los niveles socioeconómicos A y B, en la zona de Lima moderna. Para calcular la demanda del proyecto; se tomó como base el consumo promedio anual de mazamorra por hogar, obtenido de la Encuesta Nacional de Hogares (ENAHO). A esta demanda potencial, se le aplicaron los factores de segmentación definidos y el factor de corrección obtenido de las 344 encuestas realizadas. / Trabajo de investigación

Pearl millet is a cereal crop cultivated by subsistence farmers in semi-arid parts of Africa and Asia. In Namibia, pearl millet porridge is a staple food for over half of the population. Healthful Harvest, a cooperative of subsistence farmers in a rural area in Namibia is developing a flour product with extended shelf life and a short cooking time comprising pearl millet and cowpea. This requires the application of simple technology. The pearl millet grain is small (3-15 mg) but has a proportionally larger germ than all other cereal grains, except perhaps maize. Therefore, it tends to contain a high content of triglycerides, which are rich in unsaturated fatty acids. Pearl millet flour is susceptible to rancidity within a few days due to lipolysis and subsequent oxidation of the de-esterified unsaturated fatty acids. To try to prevent rancidity and to pre-cook, pearl millet grain was subjected to toasting, boiling and toasting then boiling before reduction to flour. The effects of these different thermal treatments on fat acidity, peroxide value (PV) and conjugated diene and triene values of pearl millet flour before and after three months storage at ambient conditions were determined. The degree of cook of starch was determined on fresh flours. The porridges made from the flour of the treated grains were evaluated by a trained panel and by consumers. Analyses of energy demands and practicality of the thermal treatments and extrusion cooking as processing technologies in manufacturing pearl millet flour in rural parts of Namibia were made. Fat acidity for the untreated flour increased significantly from 0.11 to 3.72 g KOH kg-1, whereas no significant increase observed in the flours of wet thermally-treated grains. This indicates that wet thermal treatments inhibited triglyceride hydrolysis. The PVs of the flours of the wet thermally-treated grain increased seven-fold, while the PV of the untreated flour decreased. A similar trend was observed for the conjugated diene values. The conjugated triene values increased significantly for all the samples. These results indicate autoxidation in the thermally-treated samples and that there was accumulation of hydroperoxides. The degree of cook of the wet thermally-treated grain (~40%) was twice that of the untreated and toasted grains, indicating that the wet thermal treatment partially gelatinised the grain. Porridges prepared using untreated flours were associated with rancid flavours, while those of other treatments were not, indicating that the thermal treatments can prevent rancidity. Consumers preferred the porridge prepared using flour of the boiled grain, presumably because it was fully cooked, whereas others were not. Thus, the boiling treatment can be applied to extend the shelf life of and pre-cook pearl millet flour. The energy demands for boiling and extrusion cooking were estimated to be 0.6 and 0.2 kWh kg-1, respectively. The energy demand for the boiling process can be minimised by sun-drying instead of using electricity. The cost of an extruder would be prohibitively costly for Healthful Harvest. Thus, boiling the grain is a suitable appropriate technology that can be applied in the Healthful Harvest situation by ordinary people, with no specialist skills. / Thesis (MSc(Agric) (Food Science and Technology))--University of Pretoria, 2007. / Food Science / MSc(Agric) / unrestricted

Please read the abstract in the section, 00front of theis document / Dissertation (MSc (Agric) Food Science and Technology)--University of Pretoria, 2008. / Food Science / MSc / Unrestricted

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MSc (Food Science and Technology) / Department of Food Science and Technology / White maize-based porridge is a staple food for about 80% consumers in South Africa and sub-Saharan African countries contributing significantly to the diet of rural populations in developing countries. White maize is deficient in some amino acids and over-dependency on its porridge may lead to high prevalence of malnutrition-related health conditions. Moringa oleifera (MO) and termite (Isoptera spp.) are known to contain a substantially high amount of protein. The aim of this study was to determine the effect of powders from MO leaves and termite on the nutritional and sensory properties of instant-maize porridge. Inclusion of MO and termite powders in instant-maize porridge, at different treatments, was considered using a completely randomised design. Factor levels were: AOB-control (maize flour); BEA (maize, powders of cooked dried MO and termite); CIA (maize, powders of blanched dried MO and termite) and DJE (maize, powders of uncooked dried MO and termite). Data were analysed using SPSS version 23. The protein content of fortified instant-maize porridge (FMP) significantly (p < 0.05) increased from 10.02 to 21.20% compared to unfortified porridges. The mineral content of FMP was higher in terms of Zn, Fe, Ca and Mg. Moisture content of FMP increased from 5.00 to 6.00%. Sensory analysis showed that among fortified porridges, CIA was rated high for colour and texture, BEA higher in taste and DJE higher for aroma. AOB had higher acceptance than fortified porridges for taste. Powder from MO leaves and termite could be used in complementary foods and food supplements to increase protein and mineral contents.