An objective analytical method was developed to characterize the taste profiles of five cheese varieties. Nonvolatile water extracts of Cheddar, Edam, Gouda, Swiss, and Parmesan cheeses were analyzed by high performance liquid chromatography (HPLC) with a reversed phase column. The HPLC operating conditions were determined with Mapping Super-Simplex followed by Centroid Mapping Optimization. A ternary gradient elution system was used with an Adsorbosphere C8 column to resolve a maximum number of components. The optimum solvent volume ratio was 96.8 : 1.2 : 2.0 for trifluoroacetic acid (0.1%), acetonitrile, and methanol, with a flow rate of 1.0 mL/min. Over 50.3 min this ratio was changed to 56.3 : 30.3 : 13.4. Multivariate statistical analyses including principal component and discriminant analyses were applied to 55 peak areas from 106 cheese chromatograms. Principal component analysis reduced the dimensionality of the "data from 55 to 17 principal components, which are-combinations of the original variables, with a 26% loss of explained sample variation. Discriminant analysis on data from a single HPLC column was able to correctly classify cheeses by variety at a greater than 90% success rate. This grouping rate dropped to 64% when data from all four HPLC columns was combined, implicating large between column variations. A semi-trained sensory panel correctly classified cheeses by variety at a 63% rate. This objective method provides a lasting fingerprint of cheese products. / Land and Food Systems, Faculty of / Graduate

Dissertation 'consists of a selection of 71 publications produced over the period 1975-2001, which were drawn from the more complete list of 198 original research papers, review articles and books published over the same period' -- declaration. / Thesis (PhD Food Sc )--Stellenbosch University, 2001. / ENGLISH ABSTRACT: One of the curious facts about the food industry is that many of the processes in use today were being practised, in some form or other, by the Roman legions as they marched across Europe and beyond. Certainly they were familiar with the basic techniques of fermentation, and much current research into fermented foods is concerned with understanding the fundamental nature of these traditional processes, and how the individual stages in a particular fermentation can be better controlled. Recent developments in the dairy industry have tended to reflect this pattern and, over the years, my research group has done much to support the expanding markets for yoghurt and similar fermented milks. Our evaluation of the polysaccharide-producing characteristics of starter cultures, for example, encouraged yoghurt manufacturers to match physical properties to the perceived demands of consumers, and most culture suppliers followed this lead by labelling their products with precise designations as to their potential for imparting viscosity to a retail item. Similarly, my group was the first to record the unique physical properties of the concentrated yoghurt, labneh, C 230 g 1-1 total solids) that had been made for hundreds of years by draining whey from natural yoghurt hanging in a cloth or animal-skin bag. This detailed analysis of the product facilitated the application of ultra-filtration to natural yoghurt to generate a product with a quality that matched traditionallabneh and, today, factories in the Middle East, Greece and elsewhere are using modern membrane-filtration plants to satisfy a growing market demand. Our success in publicising the attractive properties of concentrated yoghurt encouraged me to devote time to yet another 'historical' concept, namely the apparent 'health benefits' derived by small communities in Eastern Europe from consuming kefir and koumiss. In the West, the flavour and texture of these latter products have never been accepted, but employing similar cultures to produce 'health-promoting' bio-yoghurts opened an entirely new avenue for research. As clinical evidence in support of the prophylactic and therapeutic properties of Lactobacillus acidophilus and a species of Bifidobacterium became available, so it became apparent that the therapeutic advantage that accompanies the regular ingestion of 'bio-yoghurts' depended on the survival of these microfloras over the stipulated shelf-lives of the retail vehicles. However, no laboratory medium was immediately available for the simultaneous enumeration of Lb. acidophilus and Bifidobacterium along with the yoghurt cultures, i.e. Streptococcus thermophilus and Lactobacillus delbrueckii sub-sp. bulgaricus. Designing such a medium became a priority for one of my students, and, even today, the procedures that he derived are being used by consumer groups that monitor the performance of the major dairy companies in England. If the improved quality of yoghurts and 'bio-yoghurts' had a major impact on consumer perceptions of fermented milks, the food sector in England gradually became aware of an even more dramatic change in consumer attitudes. Thus twenty years ago, cheese meant 'Cheddar' but, following a 'deluge' of television publicity about the attractions of 'exotic' catering, housewives began demanding mozzarella and mascarpone for lavish desserts, Feta to sprinkle over salads and Halloumi to grill or fry. In turn, exporting countries like Italy, Greece and Cyprus came under intense pressure to increase supplies of top quality products. Local manufacturers soon realised, however, that there was little information available concerning the scientific basis to the procedures employed to make some of these traditional cheeses, and my research group was selected by Funding Agencies in Greece and Cyprus to act as a focus for a series of studies of Feta and Halloumi cheese. The need to eliminate pathogens from the storage brines of Feta cheese without killing the yeasts and bacteria associated with maturation became an important consideration for exporters, and one of my students exploited a novel procedure employing furocoumarins and long-wave ultra-violet light to achieve the desired selective inactivation. At present, the economics of commercial application are somewhat dubious but, as soon as cheap, synthetic, non-toxic furocoumarins become more readily available, the system may well merit re-evaluation. We did confirm, however, that the metabolic activities of the yeasts and bacteria typically isolated from storage brines are essential for flavour development in Feta cheese, and that similar microfloras are instrumental in the development of the important charactistics of traditional Halloumi cheese. In particular, a new species of lactic acid bacterium, Lactobacillus cypricasei, was isolated from samples of the traditional ovine cheese, but whether or not the species has a unique role(s) in the maturation process remains an open question. Clearly there is still much to learn but, if the activities of my reseach group have added just a little to the scientific background essential for future studies of cheese and fermented milks, then their completion will have been worthwhile. / AFRIKAANSE OPSOMMING: Een van die merkwaardigste feite omtrent die voedselindustrie is dat baie van die prosesse wat vandag gebruik word, in een of ander vorm deur die Romeinse magte gebruik is toe hulle deur Europa marsjeer het. Basiese fermentasie tegnieke was aan hulle bekend, en heelwat huidige navorsing oor gefermenteerde voedsel is gemik daarop om die fundamentele natuur van hierdie tradisionele prosesse te verstaan en hoe die individuele stappe in 'n spesifieke fermentasie beter beheer kan word. Onlangse ontwikkelinge in die suiwelindustrie reflekteer hierdie patroon, en my navorsingsgroep het oor die jare heelwat gedoen om die groeiende markte vir joghurt en soortgelyke gefermenteerde melk te ondersteun. Ons evaluasie van die polisakkariedproduserende eienskappe van suursels het byvoorbeeld joghurtvervaardigers gehelp om fisieke eienskappe daar te stel wat verbruikers tevrede sal stel. Meeste verskaffers van kulture het hierdie voorbeeld gevolg deur hul produkte so te etiketteer dat duidelik gewys word watter potensiaal dit het om viskositeit aan die finale produk te verleen. Verder was my groep die eerste om die unieke fisiese eienskappe van die gekonsentreerde joghurt, labneh (230 g 1-1 totale vastestowwe) te bepaal, wat vir honderde jare gemaak is deur die wei van natuurlike joghurt te dreineer deur dit in "n materiaal- of diervelsak te hang. "n Gedetailleerde analise van hierdie tradisionele produk het bygedra tot die gebruik van ultrafiltrasie op natuurlike joghurt om "n produk te gee met dieselfde kwaliteit as tradisionele labneh. Vandag gebruik fabrieke in die Midde Ooste, Griekeland en elders moderne membraan-filtrasie aanlegte om in die groeiende vraag na die produk te voorsien. Ons sukses met die bekendmaking van die aantreklike eienskappe van gekonsentreerde joghurt het my aangespoor om tyd te spandeer aan nog 'n sogenaamde "historiese" konsep, naamlik die skynbare gesondheidsvoordele van klein gemeenskappe in Oos-Europa wat kefir en koumiss verbruik. In die Weste is die smaak en tekstuur van hierdie produkte nooit werklik aanvaar nie, maar om soortgelyke kulture te gebruik om "gesondheidsbevorderende" bio-joghurt te produseer, het 'n hele nuwe navorsingsveld daargestel. Soos kliniese bewyse van die terapeutiese en voorkomende voordele van Lactobacillus acidophilus en 'n spesie van Bifidobacterium bekend gemaak is, het dit duidelik geword dat die terapeutiese voordele wat saamgaan met die gereelde inname van "bio-joghurts", afhang van die oorlewing van hierdie mikroflora oor die gestipuleerde rakleeftyd van die kommersiële produkte. Geen laboratorium medium was egter onmiddellik beskikbaar vir die gelyktydige telling van Lb. actdophilus en Bifldobacterium tesame met die joghurt kulture Streptococcus thermophilus en Lb. delbrueckii sub-sp. bulgaricus. Die ontwikkeling van so 'n medium het een van my studente se prioriteit geword, en selfs vandag word die prosedures wat deur hom ontwikkel is, gebruik deur verbruikersgroepe wat die optrede van groot suiwelmaatskappye in Engeland monitor. lndien die verbeterde kwaliteit van joghurts en bio-joghurts 'n groot impak gehad het op verbruikers se persepsie van gefermenteerde melk oor Wes-Europa heen, het die voedselsektor in Engeland bewus geraak van selfs 'n meer dramatiese verandering in verbruikers se houding. Twintig jaar terug het kaas "Cheddar" beteken, maar na 'n stortvloed televisie advertensies oor die aanloklikheid van eksotiese geregte, het daar by huisvroue 'n vraag ontstaan na Mozzarella en Mascarpone vir nageregte, Feta oor slaai en Halloumi om te bak of te braai. Italië, Griekeland en Siprus wat hierdie produkte uitgevoer het, het onder kwaai druk gekom om groter hoeveelhede, top-kwaliteit produkte te lewer. Plaaslike vervaardigers het gou agtergekom dat min inligting beskikbaar was oor die wetenskaplike basis van die prosedures wat gebruik word om hierdie tradisionele kase te maak en my navorsingsgroep is deur befondsingsagentskappe in Griekeland en Siprus genader om studies te doen oor sekere aspekte van die vervaardiging van Feta en Halloumi kaas. Dit het vir beide in- en uitvoerders belangrik geword om die patogene te elimineer uit die soutoplossing waarin Fetakaas gestoor word, sonder om die giste en bakterieë wat rypwording aanhelp, te dood. Een van my studente het 'n innoverende prosedure ontwikkel wat furocoumarins en lang-golf-ultra-violet lig gebruik om selektiewe inaktivering te kry. Op die oomblik is daar effense onsekerheid oor die ekonomiese implikasies van die kommersiële toepassing, maar sodra goedkoop, sintetiese, nie-toksiese furocoumarins geredelik beskikbaar word, moet die sisteem weer geëvalueer word. Ons het egter bevestig dat die metaboliese aktiwiteite van die giste en bakterieë in die stooroplossing noodsaaklik is vir geurontwikkeling in Feta kaas en dat soortgelyke mikrofloras instrumenteel is in die ontwikkeling van die belangrike karaktereienskappe van tradisionele Halloumi kaas. 'n Unieke melksuurbakterium, Lactobacillus cypricasei, is uit monsters tradisionele skaap Halloumi geïsoleer, maar of hierdie spesie 'n unieke rol speel in die verouderingsproses is nog 'n ope vraag. Duidelik is daar nog baie om te leer, maar indien my navorsingsgroep se aktiwiteite slegs 'n klein bydrae gemaak het tot die wetenskaplike agtergrond wat essensieel is vir toekomstige navorsing, was die voltooiing daarvan die moeite werd.

A ingestão de elevados teores de cloreto de sódio tem sido associada ao aumento de ocorrência de hipertensão, doenças cardiovasculares, osteoporose, incidência de nefrolitíase, síndrome metabólica e outras doenças crônicas não transmissíveis. A Agência Nacional de Vigilância Sanitária (ANVISA) avaliou 16 segmentos de alimentos industrializados e identificou que vários produtos encontraram elevados níveis de sódio, incluindo alguns produtos lácteos, destacando-se os queijos. Desse modo, o presente estudo avaliou o efeito da substituição de sódio pelo potássio nas características físico-químicas e microbiológicas de queijos Minas Padrão. O estudo consistiu na elaboração dos queijos tipo Minas Padrão Controle (C - 100% de NaCl), T1 (50% de NaCl + 50% de KCl) e T2 (30% de NaCl + 70% de KCl). Os queijos foram submetidos à avaliação microbiológica (coliformes a 35ºC e 45 ºC, Staphylococcus aureus e Salmonella sp.) e composição proximal (umidade, gordura, proteína, cinzas e cloretos) nos tempos 0 e 45 dias de estocagem a 10˚C ± 1˚C. Os teores de sódio e potássio foram quantificados aos 45 dias de estocagem. As caracterizações físico-químicas consistiram na determinação de acidez titulável, pH, índice de extensão de proteólise e índice de profundidade de proteólise nos tempos 0, 15, 30 e 45 dias de estocagem. Os queijos T1 e T2 apresentaram baixo teor de umidade comparado ao controle ao longo do tempo de estocagem. Os teores de cloretos variaram entre 0,35 e 0,44%. O teor de sódio do T1 foi de 99,33 mg e do T2 foi 73,18 mg, enquanto o teor de potássio foi de 164,39 mg e 243,45 mg para os tratamentos T1 e T2 respectivamente. Com a redução do sódio, os tratamentos T1 e T2 apresentaram menores valores de pH e elevado teor de acidez titulável aos 45 dias de estocagem comparado ao controle. O tratamento T2 apresentou aumento significativo do índice de extensão de proteólise comparado aos demais tratamentos. Por outro lado, o índice de profundidade de proteólise do tratamento controle foi superior ao índice dos demais tratamentos aos 45 dias de estocagem. Os queijos submetidos aos diferentes tratamentos apresentaram os padrões microbiológicos dentro dos limites exigidos na legislação, de acordo com a classificação quanto ao teor de umidade. Os queijos com substituição de sódio apresentaram menor teor de umidade, com elevado teor de acidez titulável inicial e menor atividade proteolítica quando comparado ao queijo controle. Portanto, a presente pesquisa demonstrou que a substituição de sódio pelo potássio na proporção de 50% e 70% não causou grandes alterações na composição proximal e não afetou as características microbiológicas das formulações de queijos. / Ingestion of large amounts of sodium chloride has been associated with increased incidence of hypertension, cardiovascular disease, osteoporosis, incidence of nephrolithiasis, metabolic syndrome and other chronic diseases. The National Health Surveillance Agency (ANVISA) evaluated 16 segments of processed foods and found that several products countains high levels of sodium, including some dairy products, standing out the cheeses. Thereby, the present study evaluated the effect of substitution of sodium by potassium on the physicochemical and microbiological characteristics of Minas Standard cheeses. The study consisted in the preparation of cheese type Minas Standard Control (C - 100% NaCl), T1 (50% NaCl + 50% KCl) and T2 (30% NaCl + 70% KCl). The cheeses were submitted to microbiological evaluation (coliforms at 35°C and 45°C, Staphylococcus aureus and Salmonella sp.) and gross composition (moisture, fat, protein, ash and chlorides) at 0 and 45 days of storage at 10°C ± 1˚C. Sodium and potassium levels were measured at 45 days of storage. The physico-chemical characterization consisted in determining titratable acidity, pH, proteolysis extension ratio and depth ratio proteolysis at 0, 15, 30 and 45 days of storage. The T1 and T2 cheeses submitted low moisture content compared to the control throughout the storage time. Chloride concentrations ranged between 0.35 and 0.44%. The content of sodium of T1 was of 99.33 mg and T2 was 73.18 mg, whilst potassium content was 164.39 mg and 243.45 mg for the treatments T1 and T2, respectively. With the sodium reduction, T1 and T2 treatments showed lower pH and higher titratable acidity levels at 45 days of storage compared to the control. The treatment T2 showed significantly proteolysis extension ratio compared to the other treatments. Besides, the depth ratio proteolysis control treatment was higher to the other treatments ratio after 45 days of storage. The cheeses from different treatments showed the microbiological standards within the limits required by law, according to the classification of the moisture content. The cheeses with sodium replacement had lower moisture content, high titratable acidity and initial lower proteolytic acidity when compared to the control cheese. Accordingly, the present research demonstrated that the substitution of sodium by potassium in ratio of 50% and 70% did not cause significant changes in the gross composition and did not affect the microbiological characteristics of cheese formulations.

O sódio é um elemento essencial na alimentação, contudo, o seu consumo excessivo está associado a problemas de saúde, tais como hipertensão, redução na absorção de cálcio, problemas renais, entre outros. Os queijos têm sido apontados como um dos produtos com elevado teor de sódio, portanto baseado neste contexto o objetivo deste trabalho foi avaliar o efeito da substituição parcial do cloreto de sódio pelo potássio nas características físico-químicas e de textura no queijo tipo Minas Padrão. A elaboração de queijos Minas padrão ocorreu com substituição do cloreto de sódio pelo potássio nas proporções de 100% de NaCl (controle), 80% de NaCl + 20% de KCl (T1), 60% de NaCl + 40% de KCl (T2), 40% de NaCl + 60% de KCl (T3) e 20% de NaCl + 80% de KCl (T4). A avaliação físico-química consistiu na determinação do teor de umidade, proteína, gordura, cinzas e cloretos nos tempos 0 e 30 dias de maturação a 12ºC. O pH, acidez titulável, índice de extensão e profundidade de maturação foram avaliados nos tempos 0, 7, 15 e 30 dias de maturação na mesma temperatura. A análise do perfil de textura consistiu na avaliação da firmeza, elasticidade, adesividade, coesividade e mastigabilidade. O presente estudo permitiu concluir que o aumento na proporção de potássio teve efeito significativo (p<0,05) nos teores de umidade, proteína e cloretos. A substituição de sódio pelo potássio aumentou o teor de umidade e reduziu o teor de proteína. Os teores de cloretos dos queijos foram inferiores a 0,6%, variando entre 0,319 e 0,594%, onde os tratamentos com maiores concentrações de potássio apresentaram diferença estatística (p<0,05) em relação aos demais. A substituição dos sais não teve efeito significativo nos teores de gordura e cinzas em todos os tratamentos. A atividade de água diminuiu com a substituição do sódio pelo potássio. O teor de sódio entre os tratamentos variou entre 157,36 e 53,85 mg.100 g-1, enquanto o teor de potássio foram de 120,72 a 364,67 mg.100 g-1, permitindo classificar os tratamentos com maiores teores de potássio como de muito baixo teor de sódio. A substituição do sódio pelo potássio não afetou significativamente o pH, índice de extensão e profundidade de maturação de todos os tratamentos. Por outro lado, houve um aumento significativo na acidez titulável nos tratamentos com menores teores de sódio. Ao avaliar os parâmetros de adesividade, elasticidade, coesividade e mastigabilidade dos queijos não diferiram estatisticamente (p>0,05) entre os tratamentos, sendo que a substituição do sódio por potássio afetou negativamente a firmeza (p<0,05) do queijo tipo Minas padrão. Portanto, a substituição do potássio em proporção inferior a 40% apresentou viável para produção de queijos Minas padrão com pouco efeito na composição proximal, físico-química e de textura. / Sodium is an essential component in the feed, however, the excessive use is associated with health problems such as hypertension, reduce calcium absorption, the renal problems, among others. The cheeses have been identified as one of the products with high in sodium, so based on this context the aim of this study was to evaluate the effect of partial substitution of sodium for potassium chloride on the physicochemical characteristics and texture of the cheese type Minas Standard. The preparation of Mines standard cheeses occurred with replacement of sodium by potassium chloride in the proportions of 100% NaCl (control), 80% NaCl 20% KCl + (T1) + 60% NaCl 40% KCl (T2 ) + 40% NaCl 60% KCl (T3) and 20% NaCl 80% KCl + (T4). The physicochemical evaluation consisted in determining the moisture content, protein, fat, ash and chlorides at 0 and 30 days of aging at 12ºC. The pH, titratable acidity, length and depth index maturation were assessed at 0, 7, 15 and 30 days of aging at the same temperature. The texture profile analysis was to assess the firmness, elasticity, adhesiveness, cohesiveness and chewiness. This study found that the increase in the proportion of potassium had a significant effect (p <0.05) in moisture, protein and chlorides. The substitution of sodium for potassium increased the moisture content and reduced the protein content. The cheese chloride levels were less than 0.6%, ranging between 0.319 and 0.594%, where the treatments with higher potassium concentrations showed statistical difference (p <0.05) than the other. The replacement of the salts had no significant effect on fat and ash in all treatments. The water activity decreased by replacing sodium by potassium. The sodium content between treatments varied between 53.85 and 157.36 g mg.100-1, while the potassium content were 120.72 to 364.67 g mg.100-1 to rank treatments with larger potassium levels as very low in sodium. The replacement of sodium by potassium did not significantly affect the pH, extent and depth index maturation of all treatments. On the other hand, there was a significant increase in titratable acidity in treatments with lower levels of sodium. When evaluating the adhesion parameters, elasticity, cohesiveness and chewiness of the cheese were not statistically different (p> 0.05) between treatments, and the sodium for potassium replacement negatively affected the strength (p <0.05) cheese type standard mines. Therefore, the substitution of potassium for less than 40% was feasible for production Mines standard cheeses with little effect on the proximal composition and physico-chemical texture.

Orientador: Walkiria Hanada Viotto / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-05T02:10:57Z (GMT). No. of bitstreams: 1 Perez_RenataMonteiro_M.pdf: 1796124 bytes, checksum: 66f219c3f85cfd192c087528bd8eef2b (MD5) Previous issue date: 2005 / Resumo: O objetivo deste trabalho foi caracterizar o consumidor e as indústrias produtoras, determinar o perfil físico-químico, sensorial e funcional dos queijos de coalho comercializados no municipio de Campinas, S.P. O estudo foi realizado em três etapas: 1) caracterização das indústrias produtoras das marcas comerciais disponíveis no mercado; 2) conhecimento do perfil do consumidor de queijo de coalho do município de Campinas; 3) avaliação das marcas de queijo de coalho comercializado em Campinas em relação à sua composição, funcionalidade e características sensoriais. Na primeira etapa, foi aplicado um questionário às indústrias produtoras das marcas de queijo de coalho utilizadas no estudo, o que gerou informações sobre as características das empresas e o procedimento de fabricação utilizado. Em geral, as indústrias são queijarias de pequeno e médio porte, que distribuem o queijo principalmente para o estado de São Paulo. Houve grande variação no processamento do queijo de coalho entre as indústrias, que utilizam procedimentos de fabricação visando inibir a ação do coagulante e do fermento láctico de modo a obter um queijo com baixa capacidade de derretimento e que não escoe pela grelha, característica mais requerida pelo mercado consumidor e determinante na compra do produto. Na segunda etapa, para se conhecer o perfil do consumidor, foi aplicado um questionário de avaliação de consumo de queijo de coalho em um hipermercado de grande influência no município de Campinas. Os consumidores do município de Campinas declararam que a principal forma de consumo do queijo é na forma grelhada e que o sabor é o atributo de qualidade mais esperado no queijo. Na terceira etapa, foram coletadas sete marcas diferentes de queijo de coalho em três ocasiões diferentes, em hipermercados e grandes supermercados do município de Campinas,S.P., com datas de fabricação similares. A composição dos queijos foi determinada e as mudanças que ocorreram durante os 90 dias de armazenamento refrigerado (proteólise, propriedades funcionais e perfil sensorial) foram monitoradas. Aos 30 e 60 dias de armazenamento, os queijos foram avaliados quanto à aceitação sensória e intenção de compra. Houve grande variação na composição dos queijos. O queijo da marca E pode ser considerado atípico, não se enquadrando nas exigências da legislação brasileira e apresentando grandes diferenças na composição, funcionalidade e propriedades sensoriais. Em geral, os queijos apresentaram pH elevado e baixa acidez titulável. Todos os queijos apresentaram baixa extensão e profundidade da proteólise resultando em queijos com baixa capacidade de derretimento e que não escoam pela grelha, característica requerida pelo mercado consumidor e determinante na compra do produto. Não houve diferença significativa na capacidade de derretimento entre as marcas analisadas e com o tempo de armazenamento refrigerado, o que foi altamente desejável, uma vez que isso determina o fim da sua vida de prateleira. A Análise Descritiva Quantitativa mostrou que as marcas avaliadas apresentaram perfis sensoriais distintos e suas características foram marcantes e bem definidas. A marca C foi a preferida pelos provadores que declararam ser o sabor, a característica mais apreciada nesse queijo. A Análise de Componentes Principais (ACP) mostrou que os queijos da marca C se caracterizaram pelos atributos sabor de manteiga e aroma de manteiga. Estes atributos, bastante valorizados pelos consumidores de queijos, podem estar relacionados ao tratamento térmico do leite (68-69ºC/5min), que foi diferente dos utilizados pelas outras marcas. O tratamento térmico diferenciado pode ter selecionado microrganismos e, consequentemente suas enzimas, capazes de produzir diacetil, composto característico do sabor e aroma de manteiga / Abstract: The objective of this work was to characterize the consumer and the producing industries, to determine the physico-chemical, sensorial and functional profile of ¿coalho¿ cheese commercialized in Campinas, S.P. The study was carried out in three steps: 1) characterization of the producing industries of commercial ¿coalho¿ cheese, found in Campinas city; 2) determination of ¿coalho¿ cheese consumer profile of Campinas, S.P.; 3) characterization of the seven brands of ¿coalho¿ cheese, found in Campinas, in relation to its composition, functionality and sensorial characteristics. In the first step, a questionnaire was sent to the seven producing industries of ¿coalho¿ cheese, which generated information on the characteristics of the companies and the used procedure of manufacture. In general, they are small to average size cheese industries that distribute the cheese mainly for the state of São Paulo. There was a large variation among cheesemaking procedure used by the industries. However, all of them use manufacture procedures aiming to inhibit or decrease the action of the coagulant and starter in order to obtain a cheese with low melting capacity which does not flow off when grilled, a characteristic required by the consummer and determinant for the purchase intention of the product. In the second step, to know the consumer profile, a questionnaire was applied at a big supermarket of Campinas city. The consumers stated the cheese is consumed mainly in the grilled form and that its flavor is the most appreciated cheese attribute. In the third step, seven different brands of ¿coalho¿ cheese, presenting similar dates of manufacture, were collected, in three different occasions, on the great supermarkets of Campinas, S.P.. The cheese composition was determined and the changes occurring during the 90 days of refrigerated storage (proteolysis, functional properties and sensorial characteristics) were monitored. At 30 and 60 days of storage, the cheeses were evaluated for sensorial acceptance and buying intention. There was a great variation on cheese composition for the different brands studied. The cheese of the brand E could be considered atypical, for not fitting the requirements of Brazilian law and for presenting great differences in composition, sensorial and functional properties as compared with other cheeses. In general, the cheeses showed high pH and low titratable acidity. All the cheeses presented low extension and depth of proteolysis resulting in cheeses with low melting capacity. There was no significant difference in the melting capacity among the studied brands and with the aging time; this fact is highly desirable because high cheese melting determines the end of its shelf life. The Quantitative Descriptive Analysis showed that the evaluated brands have distinct sensorial profiles. Each brand presented sensorial attributes that were marked and well defined. Brand C was the preferred cheese and the flavor, the most appreciated characteristic. The Principal Component Analyses (PCA), showed that the cheeses of brand C was characterized for the attributes flavor and aroma of butter. These attributes, most valued by the cheese consumers, could be related to the thermal treatment of milk (68-69ºC/5min), used only for the brand C. This different thermal treatment might have selected microorganisms and thus, enzymes able to produce diacetil, component responsible for the flavor and aroma of butter / Mestrado / Mestre em Tecnologia de Alimentos

As culturas adjuntas são amplamente utilizadas pela indústria queijeira principalmente pela sua capacidade de melhorar aroma e sabor de queijos maturados. O presente estudo avaliou o efeito da aplicação de culturas adjuntas em queijos Minas Padrão com baixo teor de gordura e substituição do cloreto de sódio por cloreto de potássio sobre as características físico-química e sensorial ao longo dos 60 dias de maturação a 14ºC. Os queijos tipo Minas padrão foram elaborados a partir de leite pasteurizado com 50% de redução de gordura, adicionados de culturas láticas compostas por Lactococcus lactis, Lactococcus cremoris (A) e Lactococcus lactis, Lactococcus cremoris, Lactobacillus helveticus e Streptococcus thermophilus (B), os quais foram salgados em diferentes proporções de cloreto de sódio e cloreto de potássio, originando os tratamentos C (100:0), T1 (50:50) e T2 (30:70). As análises físico-químicas e sensoriais foram realizadas a cada 20 dias de maturação. A avaliação sensorial consistiu na técnica de perfil livre. Após 20 dias de maturação, todos os queijos elaborados pela formulação B apresentaram-se mais úmidos e com maior retenção de sal que os queijos de formulação A, indicando a funcionalidade dos exopolissacarídeos formados pela cultura adjunta. Não houve diferença em relação ao teor de gordura e GES. Independente do tratamento de salga, os queijos da formulação B apresentaram aumento significativo no grau de proteólise secundária que repercutiu na melhoria da qualidade sensorial, pois aos 20 dias de maturação apresentaram um maior número de atributos relacionados a aroma e sabor e descrições de textura de caráter positivo tendo em vista a redução de 32 % do nível de gordura dos queijos. As análises dos queijos de formulação A demonstraram a atuação tardia da cultura no que diz respeito a formação de sabores, foram necessários 40 dias de maturação para mascarar o sabor amargo, metálico e residual oriundo das alterações realizadas. Além disso, ao longo dos 60 dias a intensidade da percepção de aroma e sabores foi reduzida e os atributos relacionados a textura indicaram com frequência um queijo quebradiço, consistente, seco e farelento, típicos defeitos causados pela redução de gordura. Desta forma é possível concluir que as culturas adjuntas contribuíram com a melhora da textura e sabor em queijo Minas Padrão com teor de gordura e cloreto de sódio reduzido. / The adjunct cultures are widely used for the cheese industry, mainly for its ability to enhance the aroma and flavor of matured cheeses. This study evaluated the effect of application adjunct cultures in cheese standard Minas with low fat content and replacement of sodium chloride by potassium chloride on the physico-chemical and sensory characteristics over 60 days of aging at 14 ° C. Cheeses type standard Mines were made from pasteurized milk with 50% fat reduction, added lactic cultures composed of Lactococcus lactis, Lactococcus cremoris (A) and Lactococcus lactis, Lactococcus cremoris, Lactobacillus helveticus and Streptococcus thermophilus (B), which were salted in different proportions of sodium and potassium chloride, yielding the C treatment (100: 0), T1 (50:50) and T2 (30:70). The physicochemical and sensory analyzes were performed every 20 days old. The sensory evaluation consisted of free technical profile. After 20 days of ripening, cheeses all prepared by formulation B showed to be more moist and greater retention of salt the formulation of the cheese, indicating the functionality of exopolysaccharides formed by the adjunct culture. There was no difference in relation to the fat content and GES. Irrespective of treatment brining, cheese formulation B showed significant increase in the degree of secondary proteolysis reflected in improved sensory quality, since after 20 days of aging showed a greater number of attributes related to aroma and flavor and character texture descriptions positive in view of the reduction of 32% fat level of the cheese. Analysis of formulation A cheese showed delayed action culture as regards the formation of flavors, it took 40 days of aging to mask the bitter and metallic aftertaste arising from changes made. Moreover, over the 60 days of the intensity of the aroma and flavor perception was reduced and the texture-related attributes indicated often a brittle cheese, consistent, dry and crumbly, typical defects caused by the reduction of fat. Thus it can be concluded that the adjunct cultures contributed to the improved texture and flavor in cheese Minas Standard with reduced fat and sodium chloride.

As culturas adjuntas são amplamente utilizadas pela indústria queijeira principalmente pela sua capacidade de melhorar aroma e sabor de queijos maturados. O presente estudo avaliou o efeito da aplicação de culturas adjuntas em queijos Minas Padrão com baixo teor de gordura e substituição do cloreto de sódio por cloreto de potássio sobre as características físico-química e sensorial ao longo dos 60 dias de maturação a 14ºC. Os queijos tipo Minas padrão foram elaborados a partir de leite pasteurizado com 50% de redução de gordura, adicionados de culturas láticas compostas por Lactococcus lactis, Lactococcus cremoris (A) e Lactococcus lactis, Lactococcus cremoris, Lactobacillus helveticus e Streptococcus thermophilus (B), os quais foram salgados em diferentes proporções de cloreto de sódio e cloreto de potássio, originando os tratamentos C (100:0), T1 (50:50) e T2 (30:70). As análises físico-químicas e sensoriais foram realizadas a cada 20 dias de maturação. A avaliação sensorial consistiu na técnica de perfil livre. Após 20 dias de maturação, todos os queijos elaborados pela formulação B apresentaram-se mais úmidos e com maior retenção de sal que os queijos de formulação A, indicando a funcionalidade dos exopolissacarídeos formados pela cultura adjunta. Não houve diferença em relação ao teor de gordura e GES. Independente do tratamento de salga, os queijos da formulação B apresentaram aumento significativo no grau de proteólise secundária que repercutiu na melhoria da qualidade sensorial, pois aos 20 dias de maturação apresentaram um maior número de atributos relacionados a aroma e sabor e descrições de textura de caráter positivo tendo em vista a redução de 32 % do nível de gordura dos queijos. As análises dos queijos de formulação A demonstraram a atuação tardia da cultura no que diz respeito a formação de sabores, foram necessários 40 dias de maturação para mascarar o sabor amargo, metálico e residual oriundo das alterações realizadas. Além disso, ao longo dos 60 dias a intensidade da percepção de aroma e sabores foi reduzida e os atributos relacionados a textura indicaram com frequência um queijo quebradiço, consistente, seco e farelento, típicos defeitos causados pela redução de gordura. Desta forma é possível concluir que as culturas adjuntas contribuíram com a melhora da textura e sabor em queijo Minas Padrão com teor de gordura e cloreto de sódio reduzido. / The adjunct cultures are widely used for the cheese industry, mainly for its ability to enhance the aroma and flavor of matured cheeses. This study evaluated the effect of application adjunct cultures in cheese standard Minas with low fat content and replacement of sodium chloride by potassium chloride on the physico-chemical and sensory characteristics over 60 days of aging at 14 ° C. Cheeses type standard Mines were made from pasteurized milk with 50% fat reduction, added lactic cultures composed of Lactococcus lactis, Lactococcus cremoris (A) and Lactococcus lactis, Lactococcus cremoris, Lactobacillus helveticus and Streptococcus thermophilus (B), which were salted in different proportions of sodium and potassium chloride, yielding the C treatment (100: 0), T1 (50:50) and T2 (30:70). The physicochemical and sensory analyzes were performed every 20 days old. The sensory evaluation consisted of free technical profile. After 20 days of ripening, cheeses all prepared by formulation B showed to be more moist and greater retention of salt the formulation of the cheese, indicating the functionality of exopolysaccharides formed by the adjunct culture. There was no difference in relation to the fat content and GES. Irrespective of treatment brining, cheese formulation B showed significant increase in the degree of secondary proteolysis reflected in improved sensory quality, since after 20 days of aging showed a greater number of attributes related to aroma and flavor and character texture descriptions positive in view of the reduction of 32% fat level of the cheese. Analysis of formulation A cheese showed delayed action culture as regards the formation of flavors, it took 40 days of aging to mask the bitter and metallic aftertaste arising from changes made. Moreover, over the 60 days of the intensity of the aroma and flavor perception was reduced and the texture-related attributes indicated often a brittle cheese, consistent, dry and crumbly, typical defects caused by the reduction of fat. Thus it can be concluded that the adjunct cultures contributed to the improved texture and flavor in cheese Minas Standard with reduced fat and sodium chloride.