Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 182-185). Also available on the Internet.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2007. / Title from title screen (site viewed June 17, 2008). PDF text: xiii, 152 p. : ill. (some col.) ; 2 Mb. UMI publication number: AAT 3293917. Includes bibliographical references. Also available in microfilm and microfiche formats.

Thesis (Ph. D.)--University of Missouri-Columbia, 1997. / Typescript. Vita. Includes bibliographical references (leaves 182-185). Also available on the Internet.

Thesis (Ph. D.)--University of Texas at Austin, 2007. / Vita. Includes bibliographical references.

Thesis(MSc Food Sc )--Stellenbosch University, 2002. / ENGLISH ABSTRACT: Consumers are becoming more health conscious. Furthermore, time is a scarce human resource and therefore convenience is an important consideration when food choices are being made. A South African food company identified this trend and decided to develop a product that capitalised on these demands of health and convenience. The decision was made to develop a low-fat, low-cholesterol, low-saturated fatty acid, low-trans fatty acid, high-fibre wheat product with an intermediate glycemic index (GI). The market in Stellenbosch was scouted to determine whether a similar product already existed. Six products that made nutrient-, health- or any other claims were identified. Not one of the identified products, however, conformed to meet the requirements of the Department of Health for the product characteristics that were set. Therefore, the decision was made to continue the development of the low-fat, low-cholesterol, low-saturated fatty acid, low-trans fatty acid, high-fibre wheat product with an intermediate glycemic index (GI). To qualify as a low-fat product, the product had to contain less than 3 % fat. The ingredients were chosen with their fat content in mind. Fruit pulp is widely used in the preparation of baked low-fat products and was also used in this study to eliminate the use of butter, margarine and oil, but also to achieve the additional product criteria that was set by the food company, namely a chewy texture and a fruity flavour. Ingredients like soya flour, oatmeal, oats and wheat bran were chosen to increase the fibre content of the product, because all of these products have a fibre content of 10 g or more per 100 g. Two products were developed during 23 experiments. Except for the high fibre claim, both products met the criteria that were set before the development started, namely a low-fat, low-cholesterol, low-saturated fatty acid, low-trans fatty acid, high-fibre content and a calculated intermediate glycemic index (GI). One of the two concept products that were developed were chosen by an experienced panel to serve as basic product for an empirical study on the effect of different fibre levels on the glycemic index. Five different fibre levels were formulated by manipulating the amounts of wheat bran and oatmeal. The basic formula contained 6,25 % fibre and the other fibre levels were identified as: 4,39; 5,31; 7,45 en 8,17 %. The fibre levels were equal-distant. The prediction was made that the GI-value of the product will decrease as the fibre levels increase and the theoretical calculations confirmed this prediction. The real GI-values that were determined by blood glucose testings, however, showed an increase in GI-value up to the 6,25 % fibre level, followed by a.decrease in GI-value to the 8,17 % fibre level. It became apparent that more than just fibre played a role in the GI-values of the products. It is proposed that the results explained by fibre behaviour, starch gelatinisation and starch hydrolysis. Hundred households in Stell enbosch tested the developed product. Two fieldworkers identified 25 consumers in four retail stores in Stellenbosch and gave them the product and the questionnaire, which they had to complete at home after tasting the product. The questionnaires were then collected from the respondents' houses. A recognised measurement instrument, which is used by the South African food industry to determine the acceptability of a newly developed product, was used for assesing the results. The results showed that the orange flavour of the product led to a low overall acceptability of the developed product and that the other product concept (that was developed during the recipe development phase and not chosen by the panel) should be considered for testing its market potential. Another facet of the questionnaire determined the effect of buying practices, health consciousness and consumer knowledge on the consumer acceptability of the low-fat, high-fibre wheat product with an intermediate-GI-value. No correlation between these factors and consumer acceptability of the low-fat, high-fibre wheat product with an intermediate-GI-value were found. / AFRIKAANSE OPSOMMING: Die verbruiker word al meer gesondheidsbewus: Terselfdertyd is tyd 'n skaars menslike hulpbron, en word gerief gevolglik 'n belangrike oorweging tydens voedselkeuses. 'n Suid-Afrikaanse voedselmaatskappy het hierdie neigings geidentifiseer en besluit om 'n produk te ontwikkel wat aan hierdie vereistes van gesondheid en gerief voldoen. Daar is besluit om 'n lae vet-, lae cholesterol-, lae versadigdevetsuur-, lae transvetsuur-, hoe veselgraanproduk met 'n intermediere glukemiese indeks (GI) te ontwikkel. Die Stellenbosse mark is verken om vas te stel of daar reeds soortgelyke produkte op die mark was. Ses produkte wat nutrientinhoud-, gesondheid- of ander aansprake maak, is geidentifiseer. Geeneen van die produkte het egter aan die Departement van Gesondheid se konsepregulasies betreffende die etikettering van voedingsmiddels vir bogenoemde produkeienskappe voldoen nie. Gevolglik is besluit om met die ontwikkeling van die lae vet-, lae cholesterol-, lae versadigdevetsuur-, lae transvetsuur-, hoe veselgraanproduk met 'n intermediere GI voort te gaan. Om as 'n laevetproduk te kon kwalifiseer, moes die produk minder as 3 % vet bevat. Die bestanddele moes dus met inagneming van hul vetinhoud gekies word. Vrugtepulp word algemeen gebruik in die bereiding van gebakte laevetprodukte en is ook in hierdie studie gebruik om die gebruik van botter, margarien of olie te vermy, maar ook om aan die addisionele produkkriteria wat deur die maatskappy gespesifiseer is, naamlik 'n sagte tekstuur en vrugtige geur, te voldoen. Bestanddele soos soja-, hawermeel, hawer- en koringsemels is gekies om die veselinhoud van die produk te verhoog, aangesien hierdie bestanddele meer as 10 g vesel per 100 g bevat. Twee produkte is deur middel van 23 eksperimente ontwikkel. Met die uitsondering van die hoeveselinhoudaanspraak, het beide produkte aan die vereistes wat gestel is, naamlik 'n laevet-, laecholesterol-, laeversadigdevetsuur-, laetransvetsuur- en 'n hoeveselinhoud en 'n beraamde intermediere GI, voldoen. Een van die konsepprodukte is deur 'n ervare paneel gekies vir die empiriese studie waar die effek van verskillende veselvlakke op die GI bepaal is. 'n Standaard formule is aangepas om vyf verskillende veselvlakke te verkry deur die koringsemel- en hawermeelhoeveelhede te manipuleer. Die basisformule het 6,25 % vesel bevat en twee veselvlakke is daarbo en -onder as ge·identifiseer: 4,39; 5,31; 7,45 en 8,17 %, dit wil sê, veselvlakke met dieselfde grootte verskille. Daar is voorspel dat die GI-waarde van die produkte sou daal met 'n toename in die veselinhoud van die produk en die teoretiese berekeninge van die GI-waarde het hierdie voorspelling gestaaf. Die werklike GI-waardes wat met behulp van bloedglukoseresponse bepaal is, het egter 'n toename in GI-waarde tot by die 6,25 % veselvlak, gevolg deur 'n afname tot by die 8,17 % veselvlak aangedui. Dit het duidelik geword dat meer as slegs die veselinhoud 'n rol gespeel het by die GI-waarde van die produk. Die resultate is gevolglik aan die hand van die veselgedrag, styselgelatinisasie en styselhidrolise verklaar. Die verbruikersaanvaarbaarheid van die ontwikkelde laevet-, hoeveselproduk is by 100 huishoudings in Stellenbosch getoets. Twee veldwerkers het die verbruikers in vier kleinhandelaars in Stellenbosch genader en produkte met 'n gepaardgaande vraelys aan hulle oorhandig. Die produkte is tuis qeevalueer en die vraelyste is weer ingesamel. Ook vervat in die vraelys was 'n erkende meetinstrument wat deur die Suid-Afrikaanse voedselindustrie gebruik word vir die bepaling van verbruikersaanvaarbaarheid van 'n nuutontwikkelde produk. Uit die resultate het dit geblyk dat die lemoengeur van die produk gelei het tot die lae verbruikersaanvaarbaarheid van die ontwikkelde produk, en dat die ander produkkonsep (wat tydens die resepontwikkelingsfase ontwikkel is, en nie deur die ervare paneel gekies is nie) vir bemarkingspotensiaal getoets hoort te word. Die data wat uit die vraelyste ingesamel is, is ook gebruik om die effek van aankooppraktyke, gesondheidsbewustheid en verbruikerskennis op die verbruikersaanvaarbaarheid van die laevet-, hoeveselgraanproduk met 'n interrnediere-Gl-waarde te bepaal. Daar is geen verwantskap tussen hierdie faktore en die verbruikersaanvaarbaarheid van die laevet-, hoëveselgraanproduk met 'n intermedlere-Gl-waarde, gevind nie.

Experiments were conducted to study the effect of treatment of rectangular bales of corn stover with aqueous ammonia and urea solutions. The stacks were covered with polyethylene sheets for 129 d, after which they were uncovered, aerated and sampled for laboratory analyses. / Master of Science

Le chrome (Cr) est un métal largement distribué sur la croûte terrestre. Les formes les plus couramment rencontrées sont le Cr (III), longtemps considéré comme un nutriment essentiel à la vie et le Cr(VI), cancérigène avéré pour l’homme. La source majeure d’exposition de la population au chrome total étant l’alimentation, des données en spéciation sont nécessaires afin d’évaluer le risque relatif à l’ingestion de chrome. La première partie de ce mémoire présente de façon générale la problématique du chrome. La deuxième partie a été consacrée à l’optimisation d’une méthode de séparation des espèces du chrome. La méthodologie des plans d’expériences a permis en un minimum d’essais d’évaluer l’influence des différentes facteurs et de leurs interactions afin de déterminer les conditions de séparation optimales. La troisième partie porte sur la mise au point d’une méthode d’extraction sélective du Cr(VI) dans les produits laitiers et céréaliers, par plan d’expériences également. Une étude de la correction des interférences et des inter conversions a également été réalisée démontrant de la justesse de la méthode. La méthode a ensuite été validée selon l’approche du profil d’exactitude et appliquée à l’analyse de 65 échantillons de produits laitiers et céréaliers ; aucune trace de Cr(VI) n’a été détectée. La quatrième partie présente le développement d’une méthode d’analyse sélective du Cr(III) dans les produits laitiers. Les performances de la méthode ont ensuite été évaluées avant son application à des échantillons réels. Les résultats confirment que le chrome total présent dans ces matrices serait bien sous forme de Cr(III). Il serait nécessaire de poursuivre ces travaux sur d’autres matrices afin de pouvoir estimer l’ensemble de l’exposition des consommateurs et de mieux évaluer les risques inhérents à la présence de chrome dans les aliments, selon sa forme présente / Chromium (Cr) is a metal widely distributed throughout the Earth’s crust. Most commonly forms found are Cr(III), which has long been considered as an essential nutrient for human health, and Cr(VI) which is carcinogenic to humans. The most important contribution to the overall exposure of total chromium in general population is through food. To improve risk assessment on the presence of chromium, there is a need to accurately determine the content of Cr(III) and Cr(VI) in food. The first part of this work focuses on the issue of chromium. The second part deals about the optimization of a separation method for chromium species. Experimental design allowed us to study effects of factors and their interactions in order to determine the best analytical conditions. Third part is the development and validation of selective alkaline extraction for Cr(VI) in dairy and cereal products, also using experimental design. A study of the correction of the interferences and of interconversions is also presented showing the accuracy of the method. Analytical performances were assessed by the accuracy profile method and the method was used to determine Cr(VI) in 65 samples of dairy and cereal products ; Cr(VI) was not detected in these samples. The last part is devoted to develop a selective determination method for Cr(III) in dairy products. Analytical performances of the method were assessed before its use to determine Cr(III) in dairy products samples. Results confirm that chromium in those matrices will be Cr(III). It would be interesting to continue this work in order to study other matrices to better assess consumer exposure and to improve risk assessment related to the presence of chromium in food, depending on its speciation

This dissertation is an empirical study of demand and supply in differentiated products markets using supermarket scanner data on two particular product categories - canned tuna and hot-breakfast cereals. First, I study the impact of retailers' price promotions on consumer demand and retailer profits in the canned-tuna product category. Since canned tuna is storable, I examine whether consumers stock up during sales. The results suggest that only a limited amount of stockpiling exists in this product category. Since inventory is not very important, consumer demand is thus modeled by a static demand model with a random-coefficients-nested-logit specification, which is estimated by the Markov Chain Monte Carlo method. The unit-sales decomposition results show that on average 36% of the demand response to price promotions comes from brand-switching, so market expansion effects due to consumers switching from the outside good and to higher quantities usually dominate the brand-switching effect. Using the demand estimates, I compute optimal retail prices assuming that stores are local monopolists and choose prices to maximize static category-level profits. I find that regular prices at "high-low" stores are typically at or slightly below the optimal prices, but that regular prices at "every-day-low-price" stores are substantially below the optimal prices. These results suggest that retail price levels and price promotions are more likely related to local market conditions such as retail competition. In addition, I study the effects of store-brand (SB) entry on the demand elasticities of incumbent national brands (NB), consumers' substitution patterns for national and store brands, and the implications for consumer welfare in the hot-breakfast-cereals product category. A random-coefficients model of consumer demand is estimated by the generalized-method-of-moments approach. The empirical findings are: (1) After the entry of SB's, demand becomes more elastic for non-imitated NB's, and either more elastic or shows no change for imitated NB's; (2) in general, substitution patterns for NB's and SB's are asymmetric, i.e., when the prices of their favorite products increase, most NB buyers tend to substitute to other NB products, but SB buyers will substitute to the corresponding imitated NB's; (3) the increase in consumer surplus due to SB entry is trivial for an individual consumer, but the aggregate benefit could be quite substantial.

Introduction: Micronutrient malnutrition has been identified as a serious health problem globally and is on the rise in South Africa. This is evident from the escalating burden of vitamin A deficiency (VAD) in South Africa. Rural infants are the most affected, as their diets often lack micronutrients. Food fortification, vitamin A supplementation and dietary diversity are the strategies that have been employed in South Africa to alleviate VAD. However, these strategies have not been effective, for various reasons. Biofortification is the production of micronutrient dense staple crops to alleviate micronutrient deficiencies. This strategy could complement existing strategies in the alleviation of VAD in South Africa and in other countries, especially in sub-Saharan Africa (SSA), where VAD is prevalent. Aim: The aim of this study was to investigate the nutritional composition and acceptance of a complementary food (soft porridge) made with provitamin A-biofortified maize by female infant caregivers from the rural areas of Umgungundlovu District of KwaZulu-Natal, South Africa. Objectives: (i) To evaluate the nutritional composition of soft porridge made with provitamin A-biofortified maize compared to non-biofortified white maize porridge; (ii) To assess the sensory acceptability of soft porridge made with the biofortified maize by black African female infant caregivers of varying age; and (iii) To determine the perceptions of the black African infant caregivers about the biofortified maize relative to the non-biofortified white maize. Methods: A cross-sectional study was conducted. Grains of two provitamin A-biofortified maize varieties and one white variety (control) were used. Grain and soft porridge of each variety of maize were analysed for their nutritional composition. The sensory acceptability of the porridges were evaluated by black African female infant caregivers, using a five-point facial hedonic scale. Focus group discussions were conducted, using some of the study subjects, to determine their perceptions about the provitamin A-biofortified maize. Results: The results showed that the grains of the provitamin A-biofortified maize varieties and their soft porridges were more nutritious than the control white variety in terms of energy, fibre, fat, protein, iron, zinc and phosphorus content. The results of the sensory evaluation indicated that there was no significant difference in the sensory acceptability of the biofortified soft porridges and the white maize soft porridge, irrespective of the age of the sensory evaluation panellists. The female caregivers perceived the biofortified maize as nutritious and health-beneficial and thought that infants would like its unique yellow colour and taste. However, the black African female caregivers perceived the provitamin A-biofortified maize as an animal feed or food for the poor. Nevertheless, the female caregivers expressed a willingness to give their infants porridge made with provitamin A-biofortified maize if it was cheap, readily available and health-beneficial. Conclusion: This study suggests that provitamin A-biofortified maize has the potential to be used as a complementary food item. Biofortification of maize with provitamin A could be used as a possible complementary strategy to assist in the alleviation of VAD in SSA. Furthermore, the relatively higher energy, fibre, fat, protein, iron, zinc and phosphorus content of the biofortified maize could contribute to the alleviation of protein-energy malnutrition and mineral deficiencies, respectively, which are prevalent in children of SSA. Although the findings of this study, like other previous studies, indicate that there are some negative perceptions about the provitamin A-biofortified maize, this study shows that provitamin A-biofortified maize soft porridge is as acceptable as white maize soft porridge to female infant caregivers from the rural areas of Umgungundlovu District of KwaZulu-Natal, South Africa. The female caregivers are thus likely to accept the biofortified maize for use as an infant complementary food in the form of soft porridge. Further research is recommended to expand the study area and consumer sample size in order to increase the confidence of inferring these results for large rural populations. / Thesis (M.Sc.)-University of KwaZulu-Natal, Pietermaritzburg, 2014.

In the theoretical part of the diploma thesis there was described food of cereal character including school nutrition programmes and their representation in the diet of basic school pupils and university students. The interview focused on the representation of cereal products and their importance in the diet is described in the research part of this diploma thesis. The interview was made in the groups of pupils in higher basic schools and university students. When evaluating the questionnaire survey, there were assessed the quantity, individual types and quality of commonly consumed cereal products and the level of eating habits of respondents in accordance with the principles of good nutrition. After evaluation of the interviews it was found that basic school pupils have worse all-day eating habits than university students. It was confirmed mostly by the answers of the questions relating to breakfast, mid-afternoon snacks and total number of meals during a day. University students prefer wholegrain products more than basic school pupils. Pupils of higher basic schools have lower knowledge level of cereals than university students.