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Com base no histórico interno da Frulact, duas leveduras (Pichia anomala e Candida intermedia) e diferentes matérias-primas, nomeadamente, coco, ananás, manga, framboesa, morango e amora, foram selecionadas com o intuito de (i) caracterizar e monitorizar a carga microbiana (ii) avaliar o comportamento das leveduras em estudo quando submetidas a diferentes binómios tempo/temperatura, nomeadamente 50, 60 e 70 °C durante 5, 15, 30, 45, 60, 90 e 120 segundos, (iii) identificar a relação de ácidos orgânicos e açúcares presentes nas matrizes de fruta e o comportamento das leveduras em estudo sujeitas a diferentes temperaturas, (iv) quantificar o desenvolvimento microbiano em iogurtes quando dosificados com preparados de fruta selecionados.
Os resultados mostraram que a carga microbiana nos frutos vermelhos foi superior à verificada em frutos tropicais (p > 0,05). A levedura C. intermedia foi mais sensível ao perfil de temperaturas testado do que P. anomala (p < 0,05). Não existiu uma correlação entre a inativação das diferentes leveduras quando inoculadas nos vários preparados e os parâmetros avaliados neste estudo, nomeadamente, pH, perfil de ácidos orgânicos e açúcares e atividade da água (p > 0,05). Concentrações mais elevadas de ácidos orgânicos e açúcares, não conferiram resistência cruzada às diferentes temperaturas (p > 0,05). Iogurtes açucarados constituíram uma matriz mais propícia ao desenvolvimento microbiano, uma vez que P. anomala é capaz de fermentar diferentes açúcares tais como a lactose, sacarose e galactose (p > 0,05). A nível sensorial observaram-se alterações nos parâmetros de aceitação dos diferentes iogurtes durante o armazenamento a 4 °C durante 31 dias.
Given Frulact's internal records, two particular yeasts (Pichia anomala and Candida intermedia) as well as several raw materials such as coconut, pineapple, mango, raspberry, strawberry and blueberry were selected with a set goal of (i) characterize and monitor it's microbial load, (ii) assess the yeasts' behaviour when subjected to different time/temperature binomials, namely 50, 60 and 70 °C during 5, 15, 30, 45, 60, 90 e 120 seconds, (iii) correlating organic acids and respective sugars present within each fruit matrices as well as evaluate the yeasts' behaviour, according to these parameters, when subjected to different temperatures, (iv) quantify the microbial development in yogurts when dosed with fruit-based preparations. The results showed that the microbial load in red berries is greater than when studied in tropical fruits (p > 0.05). The yeast C. intermedia was more sensitive to the profile of temperatures chosen than its counterpart, P. anomala (p < 0.05). There wasn’t a correlation between the inactivation of the yeasts when inoculated with the fruit-based preparations and the various parameters in which it was studied, namely: pH, the organic acids and sugars profile and water activity (p > 0.05). Higher concentrations of organic acids and sugars do not boost their cross-resistance to temperature (p > 0.05). Yogurts with sugar additions showed a more favourable environment for microbial development, given that P. anomala has the capability of fermenting several sugars such as lactose, sucrose and galactose (p > 0.05). Regarding sensory analysis, changes in the acceptance parameters of the different yogurts were observed during storage at 4 °C for 31 days.
Given Frulact's internal records, two particular yeasts (Pichia anomala and Candida intermedia) as well as several raw materials such as coconut, pineapple, mango, raspberry, strawberry and blueberry were selected with a set goal of (i) characterize and monitor it's microbial load, (ii) assess the yeasts' behaviour when subjected to different time/temperature binomials, namely 50, 60 and 70 °C during 5, 15, 30, 45, 60, 90 e 120 seconds, (iii) correlating organic acids and respective sugars present within each fruit matrices as well as evaluate the yeasts' behaviour, according to these parameters, when subjected to different temperatures, (iv) quantify the microbial development in yogurts when dosed with fruit-based preparations. The results showed that the microbial load in red berries is greater than when studied in tropical fruits (p > 0.05). The yeast C. intermedia was more sensitive to the profile of temperatures chosen than its counterpart, P. anomala (p < 0.05). There wasn’t a correlation between the inactivation of the yeasts when inoculated with the fruit-based preparations and the various parameters in which it was studied, namely: pH, the organic acids and sugars profile and water activity (p > 0.05). Higher concentrations of organic acids and sugars do not boost their cross-resistance to temperature (p > 0.05). Yogurts with sugar additions showed a more favourable environment for microbial development, given that P. anomala has the capability of fermenting several sugars such as lactose, sucrose and galactose (p > 0.05). Regarding sensory analysis, changes in the acceptance parameters of the different yogurts were observed during storage at 4 °C for 31 days.
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Pasteurização Preparados de fruta Leveduras Inativação Ácidos orgânicos Pasteurization Fruit-based preparations Yeast Inactivation Organic acids