Affiliation:
1. Universidade Norte do Paraná, Brazil
2. Animal & Grassland Research and Innovation Centre, Ireland
Abstract
Abstract: The objective of this work was to evaluate the effect of the extended cold storage of raw milk on the kinetics of fermentation on yogurt production, as well as on the product’s microbiological and physicochemical properties during shelf life. Three treatments were evaluated: yogurts made with raw milk stored for 4, 72, and 168 hours. Kinetics of fermentation was assessed through the lactic acid production rate, growth rate of Streptococcus thermophilus and Lactobacillus bulgaricus, and time to reach pH 5.0 and 4.5. The physicochemical and microbiological characteristics of raw milk and yogurts were also analyzed during cold storage at 4°C. The microbial quality of raw milk was affected by the storage time of 168 hours, with a decreasing tendency in the mesophiles:psychrotrophs ratio. Extended storage of raw milk beyond 72 hours negatively affects yogurt production, despite the low initial bacterial count, decreasing lactic acid production, S. thermophilus growth rate, pH, and protein content. Therefore, to optimize fermentation and yogurt shelf life, the maximum storage time for raw milk at 4oC should not exceed 72 hours.
Subject
Agronomy and Crop Science,Animal Science and Zoology
Reference30 articles.
1. Developing a kinetic model for co-culture of yogurt starter bacteria growth in pH controlled batch fermentation;AGHABABAIE M.;Journal of Food Engineering,2015
2. Estimation of shelf-life of concentrated yogurt by monitoring selected microbiological and physicochemical changes during storage;AL-KADAMANY E.;LWT - Food Science and Technology,2003
3. Resistance to freezing and frozen storage of Streptococcus thermophilus is related to membrane fatty acid composition;BEAL C.;Journal of Dairy Science,2001
4. Instrução Normativa nº 46, de 23 de outubro de 2007. Adota o regulamento técnico de identidade e qualidade de leites fermentados;Diário Oficial da União,2007
5. Instrução Normativa nº 62, de 29 de dezembro de 2011. Aprova o Regulamento Técnico de Produção, Identidade e Qualidade do Leite Tipo A, o Regulamento Técnico de Identidade e Qualidade de Leite Cru Refrigerado, o Regulamento Técnico de Identidade e Qualidade de Leite Pasteurizado e o Regulamento Técnico da Coleta de Leite Cru Refrigerado e seu Transporte a Granel;Diário Oficial da União,2011
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