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The effect of different temperatures on autolysis of Baker’s yeast for the production of yeast extract

This study aimed to determine the optimum autolysis conditions for the production of yeast extract, which is used to give a meaty flavor to food products and to increase their nutritional value. | Turk J Agric For 33 (2009) 149-154 © TÜBİTAK doi:10.3906/tar-0803-17 The Effect of Different Temperatures on Autolysis of Baker’s Yeast for the Production of Yeast Extract Hasan TANGÜLER, Hüseyin ERTEN* Department of Food Engineering, Faculty of Agriculture, Çukurova University, 01330 Adana - TURKEY Received: 14.03.2008 Abstract: This study aimed to determine the optimum autolysis conditions for the production of yeast extract, which is used to give a meaty flavor to food products and to increase their nutritional value. Autolysis was induced by incubating baker’s yeast cell suspensions at different temperatures (45, 50, 55, and 60 °C) with a reaction time ranging from 8 to 72 h. Content and yield of total solids, α-amino nitrogen (α-AN), and protein were determined. Yeast extract powder was obtained by drying liquid yeast extract in a pilot scale spray drier. Sensory analysis was performed by adding the yeast extract powder at different concentrations (0.5%, 1.0%, 1.5%, and 2.0%) to vegetable soup. Optimum temperature and time for the production of yeast extract was 50 °C for 24 h, based on α-AN content, which was 3.7%. Furthermore, under the same conditions, protein content was 52.5% and total solids content was 1.98%. According to sensory analysis, the sample with 0.5% yeast extract powder and the control had the highest overall acceptance. According to variance analysis, differences between total solids, α-AN, and protein content determined at 4 different temperatures, and interactions between duration and temperature were statistically significant (P ! ! =?!' ! ' ' The effects of the evaluated temperatures on protein recovery and yield during autolysis of baker’s yeast are shown in Figures 5 and 6, respectively. Protein recovery quickly increased within the first 16 h, and then there was no significant change until the end of the incubation period (Figure 5). The highest protein recovery (59.1%) released into liquid YE from cells during autolysis .