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Authors
Abstract(s)
O queijo é um dos derivados de leite mais consumidos no mundo, sendo os queijos
produzidos a partir de leite de cabra cru muito valorizados pelas suas características
organoléticas e também pela sua melhor digestibilidade, alcalinidade e pelos seus
efeitos benéficos na saúde. Durante a produção de queijo, o processo de maturação é
dinâmico e complexo, envolvendo alterações nos níveis microbiológico e bioquímico
que resultam em características organoléticas e físico-químicas únicas da variedade de
queijo. Assim, este projeto teve como objetivo monitorizar a evolução do perfil físicoquímico e microbiológico durante todo o processo de produção e de maturação de
queijo de leite de cabra cru em três lotes, permitindo identificar as alterações mais
significativas e as diferenças existentes entre os lotes. Durante a maturação ocorreram
alterações físico-químicas as quais foram registadas para diferentes parâmetros, como
pH, teor de humidade, perda de peso, teor de sal, proteólise, ácidos orgânicos, reologia
do leite do queijo, cor do queijo. Entre os parâmetros analisados, a diminuição do pH
foi influenciada essencialmente pela formação de ácido láctico, associado à prevalência
das populações de bactérias ácido-lácticas encontradas durante a maturação dos
queijos. Por conseguinte, estas bactérias produzem enzimas proteolíticas responsáveis
pela proteólise do queijo, sendo que, este processo é crucial no desenvolvimento das
propriedades texturais e sensoriais finais do queijo. Para além das bactérias ácidolácticas, outros microrganismos foram determinados, como bactérias mesofílicas totais
aeróbias, bactérias psicrotróficas aeróbias, lactobacilos, lactococos, enterococos,
Pseudomonas spp., enterobactérias, estafilococos, e leveduras e bolores, observando-se
uma dinâmica microbiana ao longo da maturação dos queijos dos vários lotes. Na
análise sensorial destes queijos, os resultados obtidos foram satisfatórios, verificandose a sua aceitabilidade pelos consumidores. Assim, foi observado que as reações
bioquímicas e microbiológicas ocorridas durante o processo de maturação, assim como,
as condições de produção e maturação interferem no perfil dos parâmetros físicoquímicos e microbiológicos. Em suma, a variabilidade observada entre lotes salienta a
relevância da padronização do leite cru usado na produção de queijo, mas também dos
processos aplicados durante a produção por forma a assegurar as propriedades físicoquímicas e organoléticas mais apreciadas pelos consumidores.
Cheese is one of the most consumed milk products in the world, being the cheeses made from raw goat milk highly appreciated for their organoleptic characteristics and also for their better digestibility, alkalinity and beneficial health effects. During cheese production, the maturation process is dynamic and complex, involving changes at the microbiological and biochemical levels that results in the unique organoleptic and physicochemical characteristics of this cheese variety. Thus, this project aimed to monitor the evolution of the physicochemical and microbiological profile of raw goat's milk cheese during the entire production and maturation processes. For that three batches were considered, allowing to identify the most significant changes and the differences among the batches. During maturation, physicochemical changes occur, such as those recorded for different parameters, such as pH, moisture content, weight loss, salt content, proteolysis, organic acids, rheology of milk and cheese, and cheese of colour. Amongst the parameters analysed, the decrease in pH was mainly influenced by the formation of lactic acid, associated with the prevalence of the lactic acid bacteria population found during cheese maturation. These bacteria produce proteolytic enzymes responsible for the proteolysis of cheese, with this process being crucial for the development of the final textural and sensory properties of the cheese. In addition to lactic acid bacteria, other microorganisms were determined, such as total aerobic mesophilic bacteria, aerobic psychrotrophic bacteria, lactobacilli, lactococci, enterococci, Pseudomonas spp., enterobacteria, staphylococci, and yeasts and molds, with a microbial dynamics being observed along the maturation of the cheeses from the different batches. In the sensory analysis of these cheeses, the results obtained were satisfactory, verifying their acceptability by consumers. Thus, it was observed that the biochemical and microbiological reactions that occurred during the maturation process, as well as, the conditions of production and maturation interfere in the profile of the physical-chemical and microbiological parameters. In sum, the variability observed between batches highlights the relevance of the standardization of raw milk used in cheese production, but also of the processes applied during production in order to ensure the physicochemical and organoleptic properties most appreciated by consumers.
Cheese is one of the most consumed milk products in the world, being the cheeses made from raw goat milk highly appreciated for their organoleptic characteristics and also for their better digestibility, alkalinity and beneficial health effects. During cheese production, the maturation process is dynamic and complex, involving changes at the microbiological and biochemical levels that results in the unique organoleptic and physicochemical characteristics of this cheese variety. Thus, this project aimed to monitor the evolution of the physicochemical and microbiological profile of raw goat's milk cheese during the entire production and maturation processes. For that three batches were considered, allowing to identify the most significant changes and the differences among the batches. During maturation, physicochemical changes occur, such as those recorded for different parameters, such as pH, moisture content, weight loss, salt content, proteolysis, organic acids, rheology of milk and cheese, and cheese of colour. Amongst the parameters analysed, the decrease in pH was mainly influenced by the formation of lactic acid, associated with the prevalence of the lactic acid bacteria population found during cheese maturation. These bacteria produce proteolytic enzymes responsible for the proteolysis of cheese, with this process being crucial for the development of the final textural and sensory properties of the cheese. In addition to lactic acid bacteria, other microorganisms were determined, such as total aerobic mesophilic bacteria, aerobic psychrotrophic bacteria, lactobacilli, lactococci, enterococci, Pseudomonas spp., enterobacteria, staphylococci, and yeasts and molds, with a microbial dynamics being observed along the maturation of the cheeses from the different batches. In the sensory analysis of these cheeses, the results obtained were satisfactory, verifying their acceptability by consumers. Thus, it was observed that the biochemical and microbiological reactions that occurred during the maturation process, as well as, the conditions of production and maturation interfere in the profile of the physical-chemical and microbiological parameters. In sum, the variability observed between batches highlights the relevance of the standardization of raw milk used in cheese production, but also of the processes applied during production in order to ensure the physicochemical and organoleptic properties most appreciated by consumers.
Description
Keywords
Análise Sensorial Diversidade Microbiana Leite Cru Maturação Parâmetros Físico-Químicos Queijo de Cabra