Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1994. / Vita. Abstract. Includes bibliographical references (leaves 105-115). Also available via the Internet.

Microorganisms have traditionally been selected for fermentation of milk on their ability to grow in milk. However nowadays the trend is towards including probiotic bacteria, i.e. those bacteria that have been suggested to provide additional health benefits to the consumer. Probiotic microorganisms have beneficial effects when ingested such as lowered incidence of colon cancer, the suppression of putrefactive and pathogenic bacteria by competitive exclusion and the production of organic acids, diacetyl and bacteriocins and a hypocholesterolemic effect, to mention but a few. To be more effective, the proposed microorganisms must be of human origin. Lactobacillus acidophilus and Bifidobacterium bifidum, which are two of the most successful probiotic bacteria used commercially, are normal inhabitants of the intestine of many animals including humans. They must however maintain their viability and activity in the bio-product in which they are formulated to be available at the right level at the time of consumption. A number of factors affect their viability, including low pH, the type of culture used and availability of essential amino acids. The choice of ingredients in the mix is crucial since it affects a number of mix properties such as pH and availability of nutrients. The demand for low fat products is a very strong driving force on the market place. However, reducing the fat content of such complex products as frozen dairy desserts is very difficult, since fat forms an integral part of the product. Removing fat poses a number of challenges as to which other ingredients to add in its place. Microparticulated whey protein concentrates have been formulated by food technologists to mimic the functionalities of fat especially as far as creaminess is concerned. Little information is available on fat replacement in frozen yoghurt, in terms of both its effects on the survival of probiotic bacteria and on some important quality parameters. Likewise, little research, if any, has been done on the perception of strawberry flavour in fat-free ice-creams and similar products. The purpose of the present study was thus to provide information on fat replacement by a microparticulated whey protein concentrate (Simplesse® 500) in frozen yoghurts and its influence on the survival of 1. acidophilus and B. bifidum. Several quality parameters of the frozen yoghurts were also evaluated. Frozen yoghurts were prepared by inoculating the mix with an ABT (acidophilus, bifidum and thermophilus) culture. Four mixes were formulated to contain 10% (m/m) milk fat, 5% (m/m) milk fat, 5% (m/m) of the microparticulated whey protein concentrate (WPC) and 3.4% (m/m) of the microparticulated WPC respectively. Decreasing milk fat from 10% to 5%, together with the addition of more milk solids-not-fat, did not lead to a significant increase (p > 0.05) in the acidity of the mix. Likewise the buffering capacity in both alkaline and acidic conditions were not significantly different (p > 0.05). Substituting fat with Simplesse® 500 at 3.4% levelled to a significant decrease in the pH of the mix (p < 0.05), which was due to the presence of more weak acids. The addition of the microparticulated WPC also led to an increase in the buffering capacity of the mix, which was due to an increase in weak acids and other buffer systems present in milk such as the citrate and phosphate systems. The addition of more Simplesse® 500 did not result in a significantly higher acidity (p > 0.05) since whey proteins are only weak acids. The viability of all three the bacteria types present in the ABT culture did not seem to be related to the presence or absence of the microparticulated WPC. The numbers of Streptococcus salivarius subsp. thermophilus, 1. acidophilus and of B. bifidum did not differ significantly (p > 0.05) between the four yoghurt mixes after incubation, ageing, whipping and freezing and three weeks of storage. However, only S. salivarius subsp. thermophilus and 1. acidophilus increased in numbers during fermentation in all the yoghurt mixes and only S. salivarius subsp. thermophilus increased significantly (p < 0.05) as a result of ageing in all the yoghurt mixes. Although the addition of the microparticulated WPC led to an increase in the acidity of the yoghurt mixes it also led to an increase in the buffer capacity, which thus helped to maintain the numbers of S. salivarius subsp. thermophilus and 1. acidophilus at the same level as in the mixes containing milk fat. While S. salivarius subsp. thermophilus and 1. acidophilus grew to numbers greater than 107 cfu/g, B. bifidum did not grow at all in any of the yoghurt mixes and the results suggest that they might not be available at the right level to have any therapeutic benefits to the consumers. Decreasing fat content led to an obvious increase in coarseness of frozen yoghurts (p < 0.05). The increasing perceived coarseness could be related to the amount of ice nuclei formed during whipping and freezing. The addition of the microparticulated whey protein concentrate could have resulted in a decrease in the freezing point, low enough to lead to a decrease in the amount of ice nuclei formed as a result of whipping and freezing. Therefore, the amount of unfrozen water available to freeze during hardening increased, thereby leading to an increase in the size of ice crystals. Fat is also known to decrease the size of ice crystals and the presence of more fat could also have led to an increased perception of smoothness. Increasing fat content led to a decrease in the perception of strawberry flavour and an increased perception of an aftertaste (p < 0.05). Fat is known to bind lipophilic compounds as well as decrease the melting rate and mass transfer, both of which will decrease the release of flavour compounds. / Dissertation (MSc (Food Science))--University of Pretoria, 2006. / Food Science / unrestricted

Performance of three carbohydrate-based fat replacers (pectin, gum, and oat fiber) in a southern-style baking powder biscuit was evaluated at substituted levels of 33%, 66%, and 100%. Objectives and sensory tests were conducted on all samples. Results were compared to the control for the determination of significant differences at (p<0.05). Overall objective test results suggested that there was an increase in the degree of expansion as the level of fat replacement increased. Significantly (p<0.05) softer crusts and crumbs were observed with the fat replaced variations. All fat-substituted biscuits had significantly (p<0.05) higher moisture contents. Upon 24 and 48 hours of storage, staling was observed in all variations with the 100% variations having the most staling. There was a significant (p<0.05) caloric reduction as the level of fat replacement increased. However, this was an over-estimation of the calories provided upon human utilization. Also, the Land and b values of the crust color significantly (p<0.05) decreased with fat sUbstitution. The QDA results indicated that the panelists observed the degree of browning, cell size, dryness, and tenderness significantly (p<0.05) decreased whereas, perceived cohesiveness significantly (p<0.05) increased as the level of fat replacement increased. Bitterness also increased as the fat replacement level increased. The general population with an Appalachian influence "moderately liked" the control and oat-based 33% and 66% variations which were selected on the basis of the QDA results. Overall, the fat substituted variations with the most desirable characteristics were the pectin and oat-based 33% biscuits. The 100% variations would be the most beneficial in caloric reduction, however, their attributes would not be representative of an "ideal" Southern-style baking powder biscuit. / Master of Science

Olestra is, a sucrose polyester, a noncaloric fat substitute, made from sucrose and several fatty acid esters. It has been approved by the FDA as a food additive used in preparing low-fat deep-frying foods such as savory snacks. Available literature on olestra was evaluated that had both positive and negative connotations. Clinical trials in numerous species of animals including humans were conducted to determine if olestra would affect the utilization and absorption of macro- and micronutrients; the effects of olestra on growth, reproduction, or its toxicity were also examined. The roles of olestra as a fat substitute, how it could effect on humans and the environment, and the potential impacts from its use in large amounts were assessed. Olestra can be removed from the environment by aerobic bacteria and fungi which may be isolated from activated sludge and soils.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 176-182). Also available on the Internet.

Thesis (M. App. Sc.)--University of Queensland, 2002. / Includes bibliographical references.

Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 176-182). Also available on the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references (leaves 136-143). Also available on the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references (leaves 136-143). Also available on the Internet.

Made available in DSpace on 2014-06-11T19:31:38Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-18Bitstream added on 2014-06-13T18:42:29Z : No. of bitstreams: 1 rechsteiner_ms_dr_botfca.pdf: 1123216 bytes, checksum: f3cc125621b00b6d9e2dd6a8f30352c0 (MD5) / O mercado de amidos vem crescendo e se aperfeiçoando, levando à busca de produtos com características específicas que atendam às exigências da indústria. Neste contexto a produção de amidos modificados é uma alternativa. Atualmente se observa uma intensa competição entre os setores de desenvolvimento de produtos nas indústrias, para oferecer aos consumidores alimentos com baixos teores de gordura. Os amidos podem sofrer várias modificações com a finalidade de serem usados como substitutos de gordura, e os amidos modificados têm-se mostrado os mais promissores substitutos de gordura. Levando em conta a importância dos amidos para o mercado de alimentos e o interesse em produtos alimentícios com menor teor de gordura, o presente trabalho teve como objetivo desenvolver substituintes de gorduras a partir de amidos de batata-doce e mandioca e avaliar o comportamento dos amidos modificados na formulação de sorvetes de massa com teores de gordura reduzidos. Para a modificação dos amidos de mandioca e batata-doce os reagentes utilizados foram tripolifosfato de sódio (STPP) e trimetafosfato de sódio (STMP) cedidos pela Astaris do Brasil S.A. Após ensaios prospectivos, definiram-se as melhores condições para a modificação dos amidos de mandioca e batata-doce. Os amidos foram fosfatados por via úmida e por via seca,em pH 9,5 com porcentagem de 5% de tripolifosfato de sódio (STPP) e 1% de trimetafosfato de sódio (STMP). A fosfatação teve início à temperatura ambiente sob agitação constante e depois de 1 hora o amido foi transferido para bandejas de alumínio forradas com plástico poliéster e levados a estufa a 130ºC por 6 horas. Os amidos modificados foram analisados quanto as suas propriedades físicas e químicas, funcionais, reológicas e por difração... / The starch market comes growing and if perfecting, leading to the search of products with specific characteristics that take care of to the requirements of the industry. In this context the modified starch production is an alternative. Currently if it observes an intense competition enters the sectors of development of products in the industries, to offer to consuming foods with low texts of fat. The starches can suffer some modifications with the purpose to be used as substitute of fat, and the modified starches have revealed the most promising substitutes of fat. Taking in account the importance of starches for the food market and the interest in nourishing products with lesser text of fat, the present work had as objective to develop fat substitutes from cassava and sweet potato starches and evaluate the behavior of starches The starch market comes growing and if perfecting, leading to the search of products with specific characteristics that take care of to the requirements of the industry. In this context the modified starch production is an alternative. Currently if it observes an intense competition enters the sectors of development of products in the industries, to offer to consuming foods with low texts of fat. The starches can suffer some modifications with the purpose to be used as substitute of fat, and the modified starches have revealed the most promising substitutes of fat. Taking in account the importance of starches for the food market and the interest in nourishing products with lesser text of fat, the present work... (Complete abstract click electronic access below)