Made available in DSpace on 2014-06-11T19:32:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-03Bitstream added on 2014-06-13T18:43:11Z : No. of bitstreams: 1 canaes_ts_dr_jabo.pdf: 1232021 bytes, checksum: b91a2c503101be8b9464eac0744c0a39 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / As características sensoriais peculiares do leite de cabra como odor e sabor acentuados, muitas vezes são consideradas desagradáveis ao consumo, tornando-se fator de recusa. Dessa forma, a alimentação tem sido um fator preponderante na manipulação dos componentes do leite, principalmente com relação ao perfil lipídico, o qual implica diretamente no seu sabor e odor. Assim, este estudo teve como objetivo avaliar as diferentes porcentagens de inclusão de capim-limão (Cymbopogon citratus (DC.) Stapf) e sua influência sobre as respostas ao estresse fisiológico via administração endovenosa de ACTH. Foram avaliados o hemograma e os parâmetros: cortisol, glicose, ureia, creatinina, albumina, fosfatase alcalina, colesterol e HDL colesterol, as características sensoriais, físicas e químicas, além do perfil lipídico do leite. Foram utilizadas 44 cabras Saanen, não gestantes, em média aos 75 dias de lactação, homogêneas quanto à idade (3 anos ± 2 meses), peso total (59,17 ± 2,69 kg), escore da condição corporal (3,0 ± 0,5) e produção diária de leite (2,58 ± 0,27 kg). O estudo foi conduzido de setembro de 2009 a fevereiro de 2010. Durante 152 dias os animais foram mantidos em sistema de confinamento em quatro baias experimentais coletivas (11 cabras/baia) sob condições climáticas e estruturais semelhantes. As quatro dietas utilizadas com relação volumoso:concentrado de 53:47, foram fornecidas uma vez ao dia após a ordenha, cuja variação foi a substituição da silagem de milho pelo capim-limão: T1 controle (concentrado + 100% de silagem de milho), T2 (concentrado + 66,5% de silagem de milho + 33,5% de capim-limão), T3 (concentrado + 33,5% de silagem de milho + 66,5% de capim-limão) e T4 (concentrado + 100% de capim-limão). Observou-se efeito quadrático no consumo de matéria seca... / The typical sensory characteristics of goat’s milk as sharp odor and taste are often considered unpleasant to consumer, becoming factor of refusal. Thus, nutrition of goats has been a factor on manipulation of milk components, especially with regard to lipid profile, which directly affects the taste and odor of the milk. The aim of this study is to evaluate levels of lemongrass (Cymbopogon citratus (DC.) Stapf) and physiological responses to stress via intravenous administration of ACTH. In this study were evaluated the blood count and the following parameters: cortisol, glucose, urea, creatinine, albumin, alkaline phosphatase, cholesterol and HDL cholesterol, the sensory, physical and chemical properties, and lipid profile of milk. For this purpose, 44 Saanen goats were used, not pregnant at 75 days of lactation, similar for age (± 3 years 2 months), weight (59.17 ± 2.69 kg), body condition score (3.0 ± 0.5) and daily milk production (2.58 ± 0.27 kg). The study was conducted from September 2009 to February 2010. During 152 days the animals were kept in feedlot pens in four experimental collective (11 goats/pen) under similar climatic and structural conditions. Four diets with roughage: concentrate of 53:47, were fed once a day after milking, whose variation was the substitution of corn silage by lemongrass: T1 control (concentrate + 100% corn silage), T2 (66.5% concentrate + corn silage + 33.5% lemongrass), T3 (concentrate + 33.5% corn silage + 66.5% lemongrass) and T4 (concentrate + 100% lemongrass). Quadratic effect in dry matter intake as the addition of lemongrass was observed. Blood leukocytes were not affected by adding lemongrass on the diet. The weight gain and milk production were higher for treatments with 66.5 and 100% of lemongrass. Although changes have been observed in glucose... (Complete abstract click electronic access below)

Orientador: João Alberto Negrão / Banca: Marcos Veiga dos Santos / Banca: Heraldo César Gonçalves / Banca: Kléber Tomás de Resende / Banca: Maria Regina Barbieri de Carvalho / Resumo: As características sensoriais peculiares do leite de cabra como odor e sabor acentuados, muitas vezes são consideradas desagradáveis ao consumo, tornando-se fator de recusa. Dessa forma, a alimentação tem sido um fator preponderante na manipulação dos componentes do leite, principalmente com relação ao perfil lipídico, o qual implica diretamente no seu sabor e odor. Assim, este estudo teve como objetivo avaliar as diferentes porcentagens de inclusão de capim-limão (Cymbopogon citratus (DC.) Stapf) e sua influência sobre as respostas ao estresse fisiológico via administração endovenosa de ACTH. Foram avaliados o hemograma e os parâmetros: cortisol, glicose, ureia, creatinina, albumina, fosfatase alcalina, colesterol e HDL colesterol, as características sensoriais, físicas e químicas, além do perfil lipídico do leite. Foram utilizadas 44 cabras Saanen, não gestantes, em média aos 75 dias de lactação, homogêneas quanto à idade (3 anos ± 2 meses), peso total (59,17 ± 2,69 kg), escore da condição corporal (3,0 ± 0,5) e produção diária de leite (2,58 ± 0,27 kg). O estudo foi conduzido de setembro de 2009 a fevereiro de 2010. Durante 152 dias os animais foram mantidos em sistema de confinamento em quatro baias experimentais coletivas (11 cabras/baia) sob condições climáticas e estruturais semelhantes. As quatro dietas utilizadas com relação volumoso:concentrado de 53:47, foram fornecidas uma vez ao dia após a ordenha, cuja variação foi a substituição da silagem de milho pelo capim-limão: T1 controle (concentrado + 100% de silagem de milho), T2 (concentrado + 66,5% de silagem de milho + 33,5% de capim-limão), T3 (concentrado + 33,5% de silagem de milho + 66,5% de capim-limão) e T4 (concentrado + 100% de capim-limão). Observou-se efeito quadrático no consumo de matéria seca... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The typical sensory characteristics of goat's milk as sharp odor and taste are often considered unpleasant to consumer, becoming factor of refusal. Thus, nutrition of goats has been a factor on manipulation of milk components, especially with regard to lipid profile, which directly affects the taste and odor of the milk. The aim of this study is to evaluate levels of lemongrass (Cymbopogon citratus (DC.) Stapf) and physiological responses to stress via intravenous administration of ACTH. In this study were evaluated the blood count and the following parameters: cortisol, glucose, urea, creatinine, albumin, alkaline phosphatase, cholesterol and HDL cholesterol, the sensory, physical and chemical properties, and lipid profile of milk. For this purpose, 44 Saanen goats were used, not pregnant at 75 days of lactation, similar for age (± 3 years 2 months), weight (59.17 ± 2.69 kg), body condition score (3.0 ± 0.5) and daily milk production (2.58 ± 0.27 kg). The study was conducted from September 2009 to February 2010. During 152 days the animals were kept in feedlot pens in four experimental collective (11 goats/pen) under similar climatic and structural conditions. Four diets with roughage: concentrate of 53:47, were fed once a day after milking, whose variation was the substitution of corn silage by lemongrass: T1 control (concentrate + 100% corn silage), T2 (66.5% concentrate + corn silage + 33.5% lemongrass), T3 (concentrate + 33.5% corn silage + 66.5% lemongrass) and T4 (concentrate + 100% lemongrass). Quadratic effect in dry matter intake as the addition of lemongrass was observed. Blood leukocytes were not affected by adding lemongrass on the diet. The weight gain and milk production were higher for treatments with 66.5 and 100% of lemongrass. Although changes have been observed in glucose... (Complete abstract click electronic access below) / Doutor

Probiotic dairy foods, especially non- and low-fat dairy products, are becoming popular in the US. A non-fat goat's milk yogurt containing probiotics (Lactobacillus acidophilus and Bifidobacterium spp.) was developed using heat-treated whey protein concentrate (HWPC) as a fat replacer and pectin as a thickening agent. Yogurts containing non-heat treated whey protein concentrate (WPC) and pectin as well as one with only pectin were also produced. A fat-free cow's milk yogurt with pectin was also used as a control yogurt. The yogurts were analyzed for chemical composition, water holding capacity (syneresis), microstructure, changes in pH and viscosity, mold, yeast and coliform counts, and probiotic survivability during storage at 4°C for 10 weeks. The results showed that the non-fat goat's milk yogurt made with 12% HWPC (12.5% WPC solution heated at 85°C for 30 min at pH 8.5) and 0.35% pectin, had a significantly higher viscosity (P<0.01) than any of the other yogurts and low syneresis than the goat’s yogurt with only pectin added (P<0.01). After 10 weeks in storage, viscosity and pH remained constant throughout all of the yogurts. Mold, yeast, and coliform counts were negative throughout the 10 week study. Bifidobacterium spp. remained stable and counts remained above 10⁶CFU g⁻ ¹ during the 10 week storage. However, the population of Lactobacillus acidophilus dropped below 10⁶CFU g⁻ ¹ after 2 weeks of storage. Microstructure analysis of the non - fat goat’s milk yogurt determined by scanning electron microscopy revealed that HWPC interacted with casein micelles to form a more comprehensive network in the yogurt gel. The results indicate that HWPC could be used as a fat replacer to improve the consistency of non - fat goat’s milk yogurt and other products alike.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-07-03T20:45:36Z No. of bitstreams: 1 MARIA VERÔNICA MONTEIRO MARINHO - DISSERTAÇÃO PPGEA 2011..pdf: 14161012 bytes, checksum: 98f60a63c6ac5eb3a86397eec9d5976f (MD5) / Made available in DSpace on 2018-07-03T20:45:36Z (GMT). No. of bitstreams: 1 MARIA VERÔNICA MONTEIRO MARINHO - DISSERTAÇÃO PPGEA 2011..pdf: 14161012 bytes, checksum: 98f60a63c6ac5eb3a86397eec9d5976f (MD5) Previous issue date: 2011-09 / Capes / O consumo do leite de cabra e de seus derivados é crescente, tendo-se como base, sua qualidade nutricional; no entanto, o sabor forte e marcante tem aceitabilidade reduzida induzindo rejeição em boa parte dos consumidores. A produção de iogurte a partir do leite de cabra combinado com polpa de frutas, pode melhorar as características sensoriais próprias do leite, mascarando seu odor característico, melhorando os teores nutricionais e, por consequência, aumentando a comercialização e o mercado. Assim sendo, objetivou-se, com esta pesquisa, a elaboração e a avaliação sensorial, química, física, físico-química e reológica de iogurte de leite de cabra adicionada de polpa de umbu {Spondias tuberosá). Foram utilizados, na elaboração das amostras, iogurte de leite de cabra, polpa de umbu, adicionada nas proporções de 10, 15 e 20%, e sacarose. Realizou-se a caracterização química, física e físico-química da polpa do umbu utilizada na elaboração das amostras. Os dados das avaliações químicas, físicas e físico-químicas da polpa foram expressos em média simples. Nas avaliações químicas, físicas e físico-químicas dos iogurtes os dados foram tratados de acordo com o delineamento inteiramente casualizado com três repetições, utilizando-se o programa Assistat. Nos iogurtes elaborados realizou-se a análise sensorial por meio de uma escala hedônica de nove pontos, na qual foram avaliados os atributos de consistência, sabor, cor, aroma, aparência, acidez e doçura e aplicados testes de aceitação; os dados foram tratados pelos programas Consensor 1.1 e Assistat, com comparação entre as médias, pelo Teste de Tukey. O estudo do comportamento reológico dos iogurtes foi realizado nas temperaturas 5, 10 e 15 °C, com leituras realizadas emviscosímetro e os dados ajustados com os modelos de Ostwald de Waelle (Lei da Potência), Casson e Mizrahi-Berk. A polpa de umbu apresentou valores de pH, acidez total titulável, sólidos solúveis totais, ácido ascórbico e teor de água, próximos aos valores reportados em literatura; em relação à cor, apresentou predominância do matiz amarelo. Para os iogurtes com diferentes concentrações de polpa de umbu o que apresentou as maiores notas médias em todos os parâmetros da avaliação sensorial, foi o iogurte de leite de cabra com 10% de polpa de umbu. Com base nos valores do pH, os iogurtes foram classificados como alimentos ácidos; em relação aos parâmetros acidez total titulável e ácido ascórbico, o iogurte de leite de cabra, com 10% de polpa de umbu, apresentou os maiores valores; não houve diferença significativa entre as formulações em relação aos sólidos solúveis totais (°Brix), proteínas, lipídios e atividade de água. Os iogurtes de leite de cabra com polpa de umbu apresentaram comportamento de fluido não newtoniano com características pseudoplásticas. Os modelos reológicos de Ostwald de Waelle, Casson e Mizrahi-Berk representaram satisfatoriamente o comportamento reológico dos iogurtes de leite de cabra com diferentes concentrações de polpa de umbu. O aumento no percentual de polpa de umbu adicionada reduziu as viscosidades aparentes dos iogurtes. / The consumption of goat milk and its derivatives is growing, due to its nutritional quality. However, its strong flavor has reduced acceptability in a considerable part of the consumer market. The production of yogurt from goat milk combined with fruit pulp can improve the sensory traits of the former by masking its characteristic aroma, improving nutritional content, thereby increasing its commercialization and market share. Thus, this study aimed at the development and sensory, chemical, physical, physico-chemical and rheological assessment of yogurt from goat's milk added to umbu pulp {Spondias tuberosa). Samples of goat milk yogurt and umbu pulp, added in proportions of 10, 15 and 20%, and sucrose, were used to elaborate the samples. We carried out the chemical, physical and physicochemical characterization of umbu pulp used in sample preparation. Data from chemical, physical and physicochemical assessments of the pulp were expressed as means. In the chemical, physical and physicochemical evaluations of the yogurts, data were analyzed in accordance with a randomized design with three replications using the Assistat program. In prepared yogurts, sensory evaluation was conducted using a nine-point hedonic scale, where we assessed consistency, flavor, color, aroma, appearance, acidity and sweetness, applying acceptance testing. Data were analyzed with Consensor 1.1 and Assistat programs, and means compared by applying Tukey's test. The study of rheological behavior was performed at 5, 10 and 15 °C, with readings performed in a viscometer and data fit to Ostwald the Waelle (Power Law), Casson, and Mizrahi-Berk models. The umbu pulp showed pH, titratable acidity, soluble solids, ascorbic acid and moisture content close to values reported in the literature, and, in terms of color, exhibited a predominantly yellowness. For yogurts with different concentrations oíumbu pulp, goat's milk (10% umbu pulp) displayed the highest mean scores in ali sensory parameters. Based on pH values, yogurts were classified as acidic foods; with respect to titratable acidity and ascorbic acid, yogurt from goat's milk with 10% umbu pulp exhibited the highest values; there was no significant difference between the formulations in terms of soluble solids (°Brix), proteins, lipids and water activity. Goat milk yogurt with umbu pulp showed non- Newtonian fluid behavior with pseudoplastic characteristics. Ostwald the Waelle, Casson, and Mizrahi-Berk rheological models adequately represented the rheological behavior of goat milk yogurt with different concentrations of umbu pulp. The increased percentage of umbu pulp reduced the apparent viscosity of the yogurts.

Consumer demand for fresher and minimally processed foods has brought about a movement to find effective, non-thermal processing technologies for the treatment of milk. The influence of temperature on bacterial reduction in UV irradiated milk was tested. Commercially processed skim, reduced fat (2%), and whole milk samples were inoculated with a naladixic acid resistant E. coli O157:H7 surrogate (ATCC 25922), maintained at or brought to 4oC and 20oC, respectively, and then exposed to a UV light dose between 5.3-6.3 mJ/cm2 for approximately 1.5 sec using the CiderSure 3500 apparatus (FPE Inc., Macedon, NY). Bacterial concentrations before and after UV exposure were enumerated and the results indicated that processing temperature was not significantly related to bacterial reduction (p > 0.05). The results did indicate that skim milk samples had a greater bacterial reduction, regardless of processing temperature compared to reduced fat milk and whole milk samples (p < 0.05). Solids such as milk fat, protein, lactose and minerals, in the milk have a greater effect over bacterial reductions than processing temperatures. Traditional goat cheeses are produced using unpasteurized milk, which increases the food safety concerns for these types of products. Fresh goat's milk was inoculated to 107 cfu/ml with Listeria monocytogenes (L-2289) and exposed to UV light using the CiderSure 3500 apparatus. Inoculated milk was exposed to an ultraviolet dose range between 0 and 20 mJ/cm2 to determine the optimal UV dose. A greater than 5-log reduction was achieved (p < 0.0001) when the milk was processed 12 times for a cumulative exposure time of roughly 18 sec and a cumulative UV dose of 15.8 +/- 1.6 mJ/cm2. The results of this study indicate that UV irradiation could be used for the reduction of L. monocytogenes in goat's milk. Organoleptic consequences of goat's milk treated with UV technology were assessed. Olfactory studies were conducted and a highly significant difference was determined between the odor of fresh goat's milk and UV processed milk (p < 0.05). The extent of lipid oxidation and hydrolytic rancidity was measured by thiobarbituric acid reactive substances (TBARS) and acid degree values (ADVs). Results indicated that as the UV dose increased, there was a significant increase in TBARS values and ADVs of the milk samples (p < 0.05). Milk samples were processed using the UV processor under the same conditions as previously described without exposure to the UV source to determine if the agitation from pumping was causing off-flavors by way of hydrolytic rancidity. The ADVs from these samples increased at the same rate as the UV irradiated samples; however, sensory studies indicated that the increase of free fatty acids (FFA) was not enough to cause detectable off-odors in the milk. Solid phase microextraction and gas chromatography (SPME-GC) was utilized to quantify the production of volatile compounds that were formed due to UV processing. The formation of pentanal, hexanal and heptanal was identified after as little as 1.3 mJ/cm2 UV dose. Peak areas were measured and analyzed after 7.8 mJ/cm2 and 15.6 mJ/cm2 and were determined to increase significantly as UV dose increased (p < 0.05). The chemical analyses supported the findings from the olfactory studies. The outcome of this research showed that UV irradiation at the wavelength 254 nm, was detrimental to certain chemical properties of fluid milk. The properties that were perceived as negative in fluid milk may be considered an attribute in certain types of cheese and future studies in the cheese production sector should be considered. Other applications for this technology could be for use in developing countries where milk is not typically processed because of the high costs of thermal pasteurization. On-farm applications for the treatment of replacement milk should also be considered. / Ph. D.