Call number: LD2668 .T4 1949 O8 / Master of Science

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Ketonic rancidity is associated with the lauric acid oils and butterfat. It arises when short and intermediate carbon chain length fatty acids (C6 to C14) are converted into methyl ketones (C5 to C13) by certain fungi. Ketonicrancidity will not occur in fats and oils that do not contain these fatty acids. Fermentation experiments with whole oils and simple triglycerides confirmed that only short and intermediate carbon chain length fatty acids were converted into methyl ketones. Methyl ketones produced contained one carbon atom less than the parent fatty acid. Tetradecanoic acid was the longest fatty acid to undergo conversion into its corresponding methyl ketone. Experiments with free fatty acids established that short and intermediate carbon chain length fatty acids inhibited the growth of Penicillium crustosum, Evidence was presented to demonstrate that the mitochondrion was a site of antifungal activity. It was concluded that the conversion of fatty acids into methyl ketones was a detoxification mechanism for their removal from the environment. Extrinsic factors (temperature, pH, aw, preservatives and O2 removal) were used to control fungal growth and ketonic rancidity. Fungal homeostatic mechanisms often enabled P.crustosum to grow under unfavourable environmental conditions. It was suggested that acombination of preservation measures should be used to prevent ketonic rancidity in the lauric acid oils and their products.

Typescript (photocopy). / Digitized by Kansas Correctional Industries

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The research in this dissertation focused on determining antioxidant effects of various natural antioxidants in cooked meat systems. Milk mineral (MM), spices, and raisin paste were used in cooked meat systems to verify their potential antioxidant properties. The MM study determined the antioxidant activity of 1.5% MM added to uncured cooked beef meatballs, and possible additive effects of MM in combination with 20-ppm or 40-ppm sodium nitrate in cooked beef sausages . There was no additive inhibition of lipid oxidation in samples containing 20-ppm or 40-ppm sodium nitrite plus 1.5% MM. Cooked meat yield was not different between control meatballs and those containing MM. As expected, treatments containing nitrite had higher redness (a*) values than samples without nitrite. The MM at 1.5% was a very effective antioxidant as compared to controls. The Garam Masala (GM) study determined the antioxidant effects and sensory attributes of the individual spices in an Indian spice blend GM in cooked ground beef, and possible additive antioxidant effects between Type I and Type II antioxidants. All spices had antioxidant effects on cooked ground beef, compared to controls without spices, with cloves being the most effective. All spices at their lowest effective recommended level effectively lowered the perception of rancid odor and rancid flavor in cooked ground beef as compared to control samples. As expected, most spices also imparted distinctive flavors to the cooked ground beef. Type II antioxidants (iron binding phosphate compounds) were more effective than individual Type I antioxidants (spices and butylated hydroxytoluene; BHT) in cooked ground beef. There was a positive additive antioxidant effect seen with rosemary + MM and rosemary + sodium tripolyphosphate (STPP) treatments as compared to individual rosemary treatment. There was no additive antioxidant effect observed for other combinations of spices with phosphate antioxidants. The raisin study was done to determine the antioxidant activity of raisin paste added to cooked ground beef, pork, and chicken. Thiobarbituric acid (TBA) values were measured using the distillation method, on the distillates, to avoid interference from sugar in the raisins. Beef, pork, and chicken flavor intensity, rancid flavor intensity, and raisin flavor intensity were evaluated by a trained sensory panel (n = 6). Addition of 2% raisin paste effectively inhibited rancid flavor development for 14 days after cooking in cooked ground beef, pork, and chicken. Sugar added at levels equivalent to that contributed by the raisins inhibited rancidity, probably due to antioxidant effects of Maillard browning products, suggesting that the antioxidant effect of raisins was due to their sugar content.

Shelf life studies of raw Macadamia integrifolia nuts were carried out at different storage temperatures, relative humidities and time. An accelerated shelf life test was conducted, and the influence of water activity on kernel texture was studied. The antioxidants naturally present were identified by the use of thin layer chromatography. Accelerated shelf life tests showed that hydrolytic rancidity followed apparent zero order kinetics within the water activity range of 0.3 to 0.5. Oxidative rancidity measured by peroxide value appeared to follow different orders of reaction at different temperatures. At two months of storage rancidity was detected at which the headspace concentration of hexanal was 0.39 ppm and a peroxide value of 0.37 meq/kg. Headspace gas chromatography was done to find a quick and effective method for measuring oxidative rancidity. The presence of natural antioxidants was verified to explain the shelf life of macadamia nuts. In textural study, correlations were found between subjective and objective measurements. The product became unacceptable organoleptically above water activity 0.415 when stored at 20 degrees C. This level was established as the critical water activity. There is a need to establish a water activity at which the consumer is likely to reject the product. / Master of Science (Hons) (Food Science and Nutrition)

Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 18, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Thesis advisor: Dr. Jeffre D. Firman. Includes bibliographical references.

The antioxidants BHA, BHT, and ascorbic acid were added to flaxmeal breads to prevent rancidity. Six types of yeast leavened breads were evaluated: control (100% bread flour), flaxmeal (15%) bread, and flaxmeal (15%) bread that contained 0.01% respectively of BHA, BHT, BHA and BHT, and ascorbic acid. Vital wheat gluten was added in all the flaxmeal breads. Chemical, objective and sensory tests were used to evaluate the breads. The crumb texture of all the experimental breads was significantly softer (p¡à 0.05) than the control breads, but the control breads were significantly moister (p¡à 0.05) than the flaxmeal breads that contained BHA and BHT, separately. No significant differences (p>0.05) were found in loaf volume of the control bread and the experimental breads. The crumb color of the experimental breads was significantly darker (p<0.0001) due to the incorporation of flaxmeal. The acid value of the flaxmeal breads was significantly higher (p¡à 0.05) than the control breads. No significant differences (p>0.05) were found in peroxide values between the control breads and experimental breads after eight weeks. The QDA sensory tests showed that breads containing BHA or in combination with BHT were moister, chewier and had the least noticeable stale taste when compared to the control breads. Ascorbic acid was not as effective as BHA or a combination of BHA and BHT in preventing lipid oxidation, but produced the softest bread. This study showed that flaxmeal breads made with BHA and BHT provided the best protection against lipid oxidation and produced a moist and chewy bread. / Master of Science

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Aiming to evaluate the oxidative stability of parboiled rice bran, coconut meal and cashew nut meal during storage and the effects of its use in the feeding of meat quails, were carried three experiments in the period 7 at 42 days of age. For this, a batch of 100 kg of each meal was stored for a period of six months. At the end of that period, were purchased new batches of 100 kg each bran, and meal, fresh and stored, were used to formulate the diets of quail. In the first experiment, 245 quails with seven days of age were distributed in a completely randomized design with five treatments and seven replications of seven birds each and were tested levels of 10 and 20% inclusion of stored parboiled rice bran (SPRB) and new (NPRB). In the second and third experiments, 280 quails with seven days of age were distributed in a completely randomized design with five treatments and seven replications of eight birds each. In these trials, the treatments consisted of a control diet and the other containing 12.5 and 25% of stored coconut bran (SCB) and new (NCB) and stored cashew nut bran (SCNB) and new (NCNB), respectively. The rice bran parboiled stored for six months showed signs of hydrolytic and oxidative reactions observed by the increase in acid value and peroxide, respectively. Regardless of the storage, the inclusion of rice bran parboiled resulted in lower digestibility of dry matter and nitrogen and higher metabolizable energy value of the diet compared to the control diet. The inclusion of 20% SPRB resulted in less metabolizable energy value of feed in relation to the addition of NPRB. Although there have been no differences between treatments in nutrient utilization ration these were not enough to significantly influence the performance, carcass characteristics, relative weight of the liver and pancreas and growth and bone quality. The coconut meal stored for six months showed a higher tendency to hydrolysis reactions, observed by increasing the acidity index. Regardless of the storage, the inclusion of coconut meal resulted in higher metabolizable energy of the ration and reduction in consumption and feed conversion compared to the control diet. Although there have been differences between treatments in some parameters, these were not sufficient to significantly influence carcass characteristics, the relative weights of the liver and pancreas and growth and bone quality. The cashew nut bran stored for six months showed a higher tendency to hydrolysis reactions, observed by increasing the acidity index. Storage independent, inclusion the cashew nut bran resulted in higher metabolizable energy of the ration and reduction in feed intake and feed compared to the control diet. Although there have been differences between treatments in some parameters, these were not sufficient to significantly influence carcass characteristics, the relative weights of the liver and pancreas and growth and bone quality. Although the store for six months promote hydrolytic and oxidative rancidity the bran of parboiled rice and hydrolytic in the coconut bran and cashew nut bran, these can be used to feed meat quails in inclusion levels of up to 20% for the parboiled rice bran and 25% for the coconut bran and cashew nut bran. / Com o objetivo de avaliar a estabilidade oxidativa do farelo integral de arroz parboilizado, do farelo de coco e do farelo de castanha de caju durante o armazenamento e os efeitos do uso desses ingredientes na alimentaÃÃo de codornas de corte, foram realizados trÃs experimentos no perÃodo de 7 a 42 dias de idade. Para isso, um lote de 100 kg de cada farelo foi armazenado durante o perÃodo de seis meses. Ao tÃrmino desse perÃodo, foi adquirido novo lote de 100 kg de cada farelo e tanto os farelos novos e armazenados, foram utilizados para formular as raÃÃes das codornas. No primeiro experimento, 245 codornas com sete dias de idade foram distribuÃdas em um delineamento inteiramente casualizado, com cinco tratamentos e sete repetiÃÃes de sete aves por unidade experimental e foram testados os nÃveis de 10 e 20% de inclusÃo de farelo integral de arroz parboilizado armazenado (FIAPA) e novo (FIAPN). No segundo e terceiro experimentos, 280 codornas com sete dias de idade foram distribuÃdas em um delineamento inteiramente casualizado, com cinco tratamentos e sete repetiÃÃes de oito aves por unidade experimental. Nesses ensaios, os tratamentos consistiram em uma raÃÃo controle e os demais contendo 12,5 e 25% de farelo de coco armazenado (FCA) e novo (FCN) e farelo de castanha de caju armazenado (FCCA) e novo (FCCN), respectivamente. O farelo integral de arroz armazenado por seis meses apresentou sinais de reaÃÃes hidroliticas e oxidativas, observados pelo aumento do Ãndice de acidez e de perÃxido, respectivamente. Independente do armazenamento, a inclusÃo do farelo integral de arroz parboilizado resultou em menor digestibilidade da matÃria seca e do nitrogÃnio e maior valor de energia metabolizÃvel da raÃÃo em relaÃÃo à raÃÃo controle. A inclusÃo de 20% de FIAPA resultou em menor valor de energia metabolizÃvel da raÃÃo em relaÃÃo à adiÃÃo do FIAPN. Embora tenha sido verificadas diferenÃas entre os tratamentos no aproveitamento dos nutrientes da raÃÃo esses nÃo foram suficientes para influenciar significativamente o desempenho, caracterÃsticas da carcaÃa, peso relativo do fÃgado e pÃncreas e o crescimento e a qualidade Ãssea. O farelo de coco armazenado por seis meses apresentou maior tendÃncia a reaÃÃes de hidrÃlise, observado pelo aumento do Ãndice de acidez. Independente do armazenamento, a inclusÃo do FC resultou em maiores valores de energia metabolizÃvel da raÃÃo e em reduÃÃo no consumo e na conversÃo alimentar em relaÃÃo à raÃÃo controle. Embora tenha sido verificadas diferenÃas entre os tratamentos em alguns parÃmetros, esses nÃo foram suficientes para influenciar significativamente as caracterÃsticas de carcaÃa, os pesos relativos do fÃgado e do pÃncreas e o crescimento e a qualidade Ãssea. O farelo de castanha de caju armazenado por seis meses apresentou maior tendÃncia a reaÃÃes de hidrÃlise, observado pelo aumento do Ãndice de acidez. Independente do armazenamento, a inclusÃo do FCC resultou em maiores valores de energia metabolizÃvel da raÃÃo e em reduÃÃo no consumo e conversÃo alimentar em relaÃÃo à raÃÃo controle. Ainda que tenha sido verificadas diferenÃas entre os tratamentos em alguns parÃmetros, esses nÃo foram suficientes para influenciar significativamente as caracterÃsticas de carcaÃa, os pesos relativos do fÃgado e do pÃncreas e o crescimento e a qualidade Ãssea. Ainda que o armazenamento por seis meses promova rancidez hidrolÃtica e oxidativa no farelo integral de arroz parboilizado e hidrolÃtica nos farelos de coco e de castanha de caju, estes podem ser utilizados na alimentaÃÃo de codornas de corte, em nÃveis de inclusÃo de atà 20%, para o farelo integral de arroz parboilizado e 25% para os farelos de coco e de castanha de caju.