The main aim of this study is to determine genetic diversity of milk protein genes associated with milk traits, namely beta-casein, kappa-casein and betalactoglobulin, in native Turkish cattle breeds (Turkish Grey, Eastern Anatolian Red, Anatolian Black, and Southern Anatolian Red) and Turkish Holstein. Only 11% deviation from the Hardy-Weinberg equilibrium and insignificant Fis values for the populations were observed, indicating that samples are free of inbreeding. B alleles of these genes, which are positively related with cheese yield and quality, seem to be relatively high in native Turkish breeds. Therefore, the results suggest that milk of Turkish native breeds is advantageous for producing high-quality and -yield cheese. A1 allele of beta-casein, which releases a bioactive peptide called BCM-7 after successive gastrointestinal proteolytic digestions, has been claimed to have adverse health effects on humans. Another aim of this study is to develop a protocol and assess the potential detrimental effects of BCM-7 on human peripheral blood cells. Despite the fact that the results are inconclusive, the optimized experimental protocol will guide further researchers while judging the effect of BCM-7 on human health. Even though A1 beta-casein, which has a low frequency in native Turkish breeds, and hence BCM-7 have no adverse health effects on humans, this probability should be enough to keep its frequency low in native cattle breeds. Bulls must be screened for A1 allele of beta-casein as well as E allele of kappa-casein, which is absent in native breeds and known to have detrimental effects on cheese quality.

Curd syneresis, a critical step in cheesemaking, directly influences the quality of cheese. The syneresis process is empirically controlled in cheese manufacturing plants. A sensor technology for this step would improve process control and enhance cheese quality. A light backscatter sensor with a Large Field of View (LFV) was tested using a central composite design over a broad range of cheese process conditions including milk pH, calcium chloride addition level, milk fat to protein ratio, temperature, and a cutting time factor (β). The research objectives were to determine if the LFV sensor could monitor coagulation and syneresis steps and provide information for predicting pressed curd moisture. Another objective was to optimize cheese yield and quality. The LFV sensor was found to monitor coagulation and syneresis and provide light backscatter information for predicting curd moisture content. A model for relating final curd moisture content with light backscatter response was developed and tested. Models for predicting whey fat losses, pressed curd moisture, and cheese yield were successfully developed (R2>0.75) using the test factors as independent variables. This was the first attempt to develop a technology for controlling pressed curd moisture using a sensor to monitor the syneresis step.

A busca por alimentos promotores de saúde é um desafio para a indústria do setor alimentício. Dessa forma muitos estudos se fazem necessários para investigar o desenvolvimento de novos produtos que mantenham as características nutricionais. O uso de ingredientes funcionais vem sendo uma alternativa para o enriquecimento nutricional e funcional desses novos produtos. Neste contexto, o objetivo deste trabalho foi desenvolver e realizar uma caracterização físico química num queijo enriquecido com microencapsulado de polpa de goiaba e inulina avaliando seu comportamento após o período de armazenamento correspondente a 20 dias a 5 ºC. Numa primeira etapa procedeu-se a obtenção do microencapsulado de polpa de goiaba por secagem em spray dryer obtendo-se partículas de tamanho médio igual a 5 μm com um rendimento de 45,46 % e eficiência de microencapsulação de 85,00 %. O microencapsulado de polpa de goiaba (MG) foi previamente caracterizado por Microscopia Eletrônica de Varredura, Espectroscopia de Absorção no Infravermelho, Espectroscopia de Ultravioleta-visível, Difratometria de Raios X, Termogravimetria que permitiram a avaliação de sua qualidade funcional e nutricional. O MG foi considerado ingrediente funcional e rico em licopeno (antioxidante natural) pois forneceu conteúdo total de carotenoides superior (64,88 μg.g-1 ± 0,52) ao da polpa de goiaba (32,62 μg.g-1 ± 4,17). Sua estabilidade, na temperatura ambiente, ante a ação e ausência da luz foi estudada e ao final de 45 dias o MG sob presença de luz apresentou um decréscimo de 96,00 % de carotenoides totais. Numa segunda etapa procedeu-se a elaboração das formulações de queijo enriquecido com MG e inulina, sendo definidas por Delineamento Composto Central Rotacional 22 totalizando 12 formulações. O perfil de textura instrumental, análise de cisalhamento, cor, atividade de água, carotenoides totais, atividade antioxidante (DPPH e ABTS), umidade, lipídeos, proteínas, carboidratos (obtidos por diferença), cinzas, conteúdo de cloreto de sódio, Extrato seco (ES), Gordura no estrato seco (GES), pH e valor calórico, foram avaliados ao final de maturação sob refrigeração de 20 dias. Assim, cada variável resposta apresentou um modelo quadrático, os quais foram preditivos em ordem decrescente do coeficiente de correlação para lipídeos, carotenoides totais, fator chroma a*, GES, hºab e valor calórico (R2 (%) = 96,55; 93,12; 88,31; 80,39; 80,29; 78,50, respectivamente). A formulação T4 destacou-se devido ao maior enriquecimento com carotenoides totais (5,0 μg.g-1) e inulina, a qual cumpriu seu papel como substituto de gordura. Estes resultados confirmaram em todos os modelos gerados e igualmente comprovados pela análise de componentes principais que T4 foi a melhor formulação. / The search for health-promoting foods challenges the food industry. Therefore many studies are required in order to investigate the development of new products that retain the same nutritional characteristics. The use of functional ingredients has been an useful alternative for the nutritional and functional enrichment of new products. In this context, the aim of this study was to develop and characterize the physical-chemical composition of a cheese enriched with a guava pulp microencapsulated and inulin and then evaluating their behavior during the respective storage period of 20 days under 5°C. The first stage proceeded by drying the guava pulp with a spray dryer to obtain a 5μm average particle size microencapsulated with 45.46% of efficiency and a 85.00% of microencapsulation efficiency. The guava pulp microencapsulated (MG) was previously characterized by Scanning electron microscope, Reflection Absorption Infrared Spectroscopy, Ultraviolet-visible spectroscopy, X-ray diffraction and thermo-gravimetry, which provided the evaluation of its functional and nutritional quality. The MG was considered a functional ingredient rich in lycopene (natural antioxidant) as provided by the total content of carotenoids higher (64.88 ± 0.52 μg.g-1) than the guava pulp (32.62 ± 4,17 μg.g-1). Its stability at room temperature, compared to the reaction in presence and absence of light was studied, and in the end of 45 days the MG in presence of light decreased its total of carotenoids by 96.00%. In a second step it was proceeded the preparation of cheese formulations enriched with MG and inulin, defined by 22 Central Composite Rotational Delineation totalizing 12 samples. The instrumental texture profile, shear analysis, color, water activity (aw), carotenoids, antioxidant activity (DPPH and ABTS), moisture, lipids, proteins, carbohydrates (obtained by difference), ashes, sodium chloride, dry matter (DM), fat in dry matter (FDM), pH and caloric value were evaluated at the end of 20 days of maturation under refrigeration. Thus, each response variable showed a quadratic model, which was predictive in descending order of the correlation coefficient for lipids, carotenoids, chromaa*, GES, hºab and caloric value (R2 (%) = 96.55 ; 93.12; 88.31; 80.39; 80.29; 78.50, respectively). The T4 formulation stood out in the study with the greatest enrichment with carotenoids (5.0 μg.g-1) and inulin, which fulfills its role as a fat substitute. T4 stood out in all generated models, a fact also confirmed by the principal component analysis. / 5000

Please read the abstract in the section 00front of this document / Thesis (PhD (Food Science))--University of Pretoria, 2006. / Food Science / unrestricted

O objetivo desse estudo foi validar a aplicação da metodologia isotópica de identificação da origem dos gliceróis em gorduras presentes em requeijões e especialidades lácteas com o intuito de oferecer uma ferramenta de controle de qualidade, de fiscalização de mercado e detecção de fraudes. Para atingir esse objetivo, isolou-se o glicerol de compostos lácteos como requeijões, especialidades lácteas, leite e óleos vegetais (empregados como padrões de origem animal e vegetal, respectivamente) e aplicou-se a metodologia isotópica. O glicerol foi isolado através da centrifugação. Foram analisadas todas as marcas de requeijões e similares (28 marcas) disponíveis nos supermercados da cidade de Piracicaba, e depois, agrupadas conforme sua identificação: requeijão cremoso, especialidade láctea com requeijão cremoso, alimento à base de requeijão e creme vegetal, requeijão cremoso com amido e não identificado. Do total, cinco marcas apresentaram resultados com diferença significativa (p<0,05) quando comparados ao controle (padrão animal - leite). A metodologia isotópica permitiu identificar a origem do material analisado e detectar alterações nos padrões. Comprovou-se a eficácia da metodologia isotópica na identificação da origem da matéria graxa de requeijões e a aplicabilidade da técnica no controle de qualidade de lácteos, auxiliando tanto no recebimento de matéria-prima como de produto final. / The objective of this study was to validate the application of the isotopic methodology of identification of glycerol origin in the fat fraction of "requeijões" (Brazilian soft cheeses) and similar products aiming at the identification of a quality control instrument for market fiscalization and fraud detection. In order to pursue the specific objectives of this study, the glycerol was isolated from spreadable dairy products such as "requeijões" and others. Cow's milk and vegetable oils of known origins were adopted as standards. The isotopic methodology was applied to identify the origin of the carbon present in the glycerol molecule of the fats present in those foods. Glycerol was isolated according to a conventional based on centrifugation. Twenty-eight commercial brands of "requeijões" available in the supermarkets of Piracicaba city were classified according to the information provided in the lables and analyzed. Out of the total, 5 brands were significantly different (p<0,05) when compared to the control (animal pattern - milk), indicating absence of the milk fat in the formulation. The isotopic methodology allowed to identify the origin of the analyzed material and to detect alterations in the patterns. The effectiveness of the isotopic methodology in the identification of origin of the lipid constituents of "requeijão" was proven as well as the applicability of the technique in dairy industry quality control, both in the final product as well as in process supplies.

O objetivo desse estudo foi validar a aplicação da metodologia isotópica de identificação da origem dos gliceróis em gorduras presentes em requeijões e especialidades lácteas com o intuito de oferecer uma ferramenta de controle de qualidade, de fiscalização de mercado e detecção de fraudes. Para atingir esse objetivo, isolou-se o glicerol de compostos lácteos como requeijões, especialidades lácteas, leite e óleos vegetais (empregados como padrões de origem animal e vegetal, respectivamente) e aplicou-se a metodologia isotópica. O glicerol foi isolado através da centrifugação. Foram analisadas todas as marcas de requeijões e similares (28 marcas) disponíveis nos supermercados da cidade de Piracicaba, e depois, agrupadas conforme sua identificação: requeijão cremoso, especialidade láctea com requeijão cremoso, alimento à base de requeijão e creme vegetal, requeijão cremoso com amido e não identificado. Do total, cinco marcas apresentaram resultados com diferença significativa (p<0,05) quando comparados ao controle (padrão animal – leite). A metodologia isotópica permitiu identificar a origem do material analisado e detectar alterações nos padrões. Comprovou-se a eficácia da metodologia isotópica na identificação da origem da matéria graxa de requeijões e a aplicabilidade da técnica no controle de qualidade de lácteos, auxiliando tanto no recebimento de matéria-prima como de produto final. / The objective of this study was to validate the application of the isotopic methodology of identification of glycerol origin in the fat fraction of "requeijões" (Brazilian soft cheeses) and similar products aiming at the identification of a quality control instrument for market fiscalization and fraud detection. In order to pursue the specific objectives of this study, the glycerol was isolated from spreadable dairy products such as "requeijões" and others. Cow's milk and vegetable oils of known origins were adopted as standards. The isotopic methodology was applied to identify the origin of the carbon present in the glycerol molecule of the fats present in those foods. Glycerol was isolated according to a conventional based on centrifugation. Twenty-eight commercial brands of "requeijões" available in the supermarkets of Piracicaba city were classified according to the information provided in the lables and analyzed. Out of the total, 5 brands were significantly different (p<0,05) when compared to the control (animal pattern - milk), indicating absence of the milk fat in the formulation. The isotopic methodology allowed to identify the origin of the analyzed material and to detect alterations in the patterns. The effectiveness of the isotopic methodology in the identification of origin of the lipid constituents of "requeijão" was proven as well as the applicability of the technique in dairy industry quality control, both in the final product as well as in process supplies.