Thesis (D. Tech.) -- Central University of Technology, Free State, 2010 / Branded dairy products have lately become a global trend. As a result of this, the origin of the milk used in the manufacturing of branded cheeses must be declared by the producer, since it is known that these products are highly adulterated with foreign milk. In South Africa, branded Ayrshire Cheddar cheese has become highly popular due to its unique organoleptic properties and in light of claims that it ripens much faster than cheese made from other milk (not including Ayrshire). This study was therefore directed to investigate the unique properties of branded Ayrshire Cheddar cheese versus Cheddar cheese manufactured from a mixture of other breeds’ milk (not including Ayrshire milk) and to establish a catabolite profile for each cheese type. The outlay of the thesis was constructed into six chapters each with its own outcomes. The first chapter focused on the variations between the two Cheddar cheese batches (produced from Ayrshire and other breeds’ milk) with regards to organic acid, selected chemical parameters and starter microbiotia. In the following three chapters mathematical models were developed that would predict organic-; fatty and amino acid fluxtuations respectively in the cheese made from Ayrshire and other milk. In the last chapter two artificial neural networks were designed with the two starter organisms, Lactococcus lactis and Streptococcus thermophilus as variable indicator respectively. Thirty-two cheese samples of each batch (pure Ayrshire (4) / mix breed with no Ayrshire (4)) were ripened and samples were analysed under the same conditions on the following days after production: 2, 10, 22, 36, 50, 64, 78, and 92. In the subsequent chapters, the following analysis were done on each day of analysis: organic acid by means of high performance liquid chromatography (HPLC); fatty acids by means of Gas Chromatography Mass Spectometry (GCMS); amino acids by means of GC-MS; microbial analysis by means of traditional methods, total DNA extraction and polymerase chain reaction (PCR); and standard chemical analysis for moisture, NaCl and pH. In the first research chapter, the minimum and maximum (min/max) values, standard deviations and proposed rel X values of organic acids were evaluated in Ayrshire and the mixed-breed Cheddar cheese, and showed that isovaleric acid is the organic acid with the least variation relative to concentration in both cheeses and it was assumed that this organic acid is the most effective indicator of cheese uniformity. Clear differences in organic acids, chemical variables and starter micro-organisms were also evident in the two cheese batches. Results obtained from the regression models which was defined for each organic -; amino - and fatty acid by means of mathematical equations can be used by the manufacturer to achieve i.e. the selection of cheese for specialist lines, the early exclusion of defective cheeses, and the establishment of brand origin (Ayrshire vs. mixed-breed Cheddar cheeses). The regression graphs also illustrate unique flux patterns in Ayrshire and the mixed-breed in terms of organic -, fatty -, and amino acid content. In the last chapter, the discrimination between the two batches was respectively done via artificial neural network (ANN) modelling of Lactococcus lactis and Streptococcus thermophilus as indicator organisms. The ANN consisted of a multilayered network with supervised training arranged into an ordered hierarchy of layers, in which connections were allowed only between nodes in immediately adjacent layers. The construction thereof allowed for two output nodes, connected to an input layer consisting of two nodes to which the inputs were connected. In both cheeses the results from the ANN showed acceptable classification of the cheeses based on the counts of L. lactis and S. thermophilus.

Raw milk cheese has unique flavor and textural characteristics not obtainable in cheese from pasteurized milk. Several specialty cheeses made from raw milk are marketed worldwide, especially in Europe. However, because of safety concerns, many countries have imposed stringent restrictions on production and sale of raw milk cheeses. The purpose of this thesis research was to use high pressure (HP) treatment as a novel alternative for conventional pasteurization so that raw milk quality cheese could be produced without compromising food safety. The specific objectives of this research were to evaluate (i) the effect of HP treatment of milk on its coagulation and gelation characteristics, (ii) the destruction kinetics of microorganism and enzymes in milk, (iii) cheese making characteristics of HP treated milk as compared to the raw, pasteurized and micro-filtered milk (controls) and, finally (iv) to evaluate ripening characteristics of cheddar cheese made from HP treated milk in comparison with the controls. / Three coagulation parameters of milk---lag time, mean coagulation rate, and inflexion time (time for reaching the point of maximum coagulation rate)---were evaluated as a function of pressure (200--400 MPa), temperature (3--21°C) and holding time (10--110 min) using a response surface methodology. In general, the lag time and inflexion time decreased while the mean coagulation rate increased with an increase in pressure, holding time or a decrease in temperature: The rennet gel characteristics were evaluated as gel strength (GS) and water-holding capacity (WHC). With a decrease in pressure level, temperature and holding time, there was a decrease in water-holding capacity and an increase in the gel-strength of the rennet curd. (Abstract shortened by UMI.)

The application of high pressure (HP) processing on raw milk cheese was investigated in order to assure safety and improve quality. Fresh raw milk cheese inoculated with contaminant, spoilage and pathogenic microorganisms (Escherichia coli K-12, E. coli O157:117 and Listeria monocytogenes), as well as natural micro-flora, were subjected to UP treatment at selected pressures (200--400 MPa) for various holding times (0 to 100 min), or number of pulses. HP destruction of microorganisms followed the dual effect destruction behavior involving a step change in the population due to a pressure pulse (pulse effect, PE) and a first order rate log-linear kinetics during the pressure hold. The pressure dependency of kinetic parameters followed the pressure destruction time (PDT) and Arrhenius type models. / The results suggest that high pressure treatment as a powerful tool for microbial control do not result in major change in raw milk cheese quality properties (color and texture). It would thus be an effective method of inactivation of spoilage bacteria and pathogens for ensuring safety and keeping the quality of raw milk cheese.

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

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The objective of this study was to develop a decision making tool to determine economic feasibility of artisan cheese operations. A survey of current Oregon artisan cheese companies was used to gain knowledge of the fixed and variable costs associated with cheese production and business start-up. The data from this survey was used to design a business model within Microsoft Excel 2010 that effectively describes the business environment in which an artisan cheese company could exist. Economic feasibility was determined through net present value (NPV) and Internal Rate of Return (IRR) of the investment. The model estimates size of the production and aging facilities based on production volume and cheese types produced. The application of the tool is demonstrated in this study through testing of several scenarios within each area of investigation: impact of milk pricing, cheese styles, product retail price, and geographical location of the creamery. The model also predicts the minimum product retail pricing necessary to ensure a positive NPV of the potential venture at several sizes of production and across several different styles of cheeses. / Graduation date: 2012

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv., 2002. / Härtill 5 uppsatser.

O queijo regional fabricado exclusivamente no Sudoeste do Paraná, com cultura lática autóctone proveniente de microrganismos do leite de produtores da região, tem a finalidade de comercialização e valorização de produtos lácteos com características regionais. Este estudo teve como objetivo avaliar as modificações microbiológicas, químicas e físicas do queijo produzido com duas culturas láticas autóctones (fermento A e B) da região Sudoeste do Paraná durante o processo de maturação em 0, 60 2 120 dias. Os parâmetros físico-químicas evoluíram de forma esperada durante a maturação, apresentando diminuição da aw, pH e umidade, e aumento nos parâmetros de acidez (em ácido lático e ácido graxos), sólidos totais, proteína total, lipídios, gordura no extrato seco e cinzas. S. thermophillus apresentou maior contagem no início da maturação em comparação ao L. delbrueckii sp. bulgaricus e valores próximos nos períodos 60 e 120 dias. A proteólise (IEP e IPP) aumentou durante a maturação. O perfil de ácidos graxos apresentou maior porcentagem os ácidos palmítico, oleico, esteárico e mirístico, sendo que vários ácidos graxos apresentaram diferença entre os queijos em diferentes períodos da maturação. A cor do queijo regional durante a maturação apresentou diminuição da luminosidade, aumento da cor verde e amarela. A textura do queijo apresentou diminuição dos parâmetros de coesão, elasticidade e mastigabilidade, sendo que dureza não apresentou diferença durante a maturação. Os queijos fabricados com o fermento A (QA) e B (QB) apresentaram diferenças entre si ao 0 dia para acidez em ácido lático, acidez em ácidos graxos, umidade, sólidos totais, potássio, cálcio, IPP, L*, b* e elasticidade. Já aos 60 dias as análises de acidez em ácido lático, IEP e S. thermophillus diferiram entre QA e QB e aos 120 dias apenas os parâmetros de cor a* e b*. O teste de correlação linear para cor apresentou correlação com atividade de água, umidade, sólidos totais, lipídios, NS pH 4,6 e NS TCA 12% para as coordenadas L* e a*, já a coordenada b* apresentou somente correlação para lipídios. Os parâmetros de textura (coesão, elasticidade e mastigabilidade) apresentaram correlação com os parâmetros químicos avaliados (atividade de água, umidade, sólidos totais, proteína - exceto elasticidade, lipídios, NS pH 4,6, NS TCA 12%). Com o estudo agregou-se novos dados no desenvolvimento do queijo regional durante a maturação, principalmente na evolução da proteólise, contagem de bactérias ácido-láticas, perfil de ácidos graxos e correlação entre parâmetros químicos, de cor e textura. Observou-se também atuação distinta entre os dois fermentos apenas no início da maturação dos queijos, sendo que, não será comercializado o produto neste período. / The regional cheese which is made exclusively in the southwestern region of Paraná State, with autochthonous lactic culture from milk microorganisms of producers from the region, has the purpose of both marketing and enhancement of dairy products with regional characteristics. This study aimed to evaluate the microbiological, chemical and physical changes of the cheese produced with two indigenous lactic cultures (yeast A and B) of Paraná Southwest region during the maturation process at 0, 60 2120 days. The physicochemical parameters evolved, as expected during maturation, with aw, pH and moisture decreasing and increasing acidity parameters (in lactic acid and fatty acid), total solids, total protein, lipid, fat in dry matter and ashes. S. thermophilus showed the highest score at the start of maturation when compared to the L. delbrueckii sp. bulgaricus and values near the periods 60 and 120 days. The proteolysis (IEP and IPP) increased during maturation. The fatty acid profile showed a higher percentage of palmitic, oleic, stearic and myristic, and various fatty acids showed differences between cheeses at different stages of maturation. The color of regional cheese during maturation has shown a reduction on brightness and on the other hand an increase of green and yellow color. The cheese texture showed decreased cohesion parameters, elasticity and chewiness, and toughness showed no difference during maturation. Cheeses made with yeast A (QA) and B (QB) differ from each other to 0 days to acidity in lactic acid acidity in fatty acids, moisture, total solids, potassium, calcium, IPP, L *, b * and elasticity. At 60 days, the acidity analysis in lactic acid, IEP and S. thermophilus differed between QA and QB and 120 days only the color parameters a * and b *. The linear correlation test for color correlated with water activity, moisture, total solids, lipids, NS pH 4.6 and NS TCA 12% for L * a * coordinate and, as the coordinate b * only correlated to lipids. The texture parameters (cohesion, elasticity and chewiness) correlated with the assessed chemical parameters (water activity, moisture, total solids, protein - except elasticity, lipids, NS pH 4.6, NS TCA 12%). According to the study in the development of regional cheese during maturation, new data has been added especially in the evolution of proteolysis count lactic acid bacteria, fatty acid profile and correlation between chemical parameters, color and texture. It was also observed distinct performance between the two yeasts only at the beginning of the maturation of both cheeses, which will not be marketed at this point.

Food industry occupies a prominent place in branch of process engineering. From design process equipment point of view, great emphasis is placed on hygienic requirements, accuracy, reliability and above all safety. The diploma thesis is focused on comprihensive design of milk heating technology for cheese production with high-temperature curd. The diploma thesis describes technological and constructional design of technology. The diploma thesis also contains basic design of measurement and regulation.