Kinetics of brewers yeast hydrolysis, 2: brewers yeast hydrolysis catalysed by acids
1998
Baras, J. (Tehnolosko-matalurski fakultet, Beograd (Yugoslavia)) | Maslic, M. | Turubatovic, L.
The paper presents the results of acid hydrolysis of spent brewers yeast with sulphuric acid under pH value 5.2 in the period of 30 hours in the temperature range 45-65 deg C, as well as the results of acid hydrolysis with lactic acid under pH values 5.0, 5.5 and 6.0 in the same temperature range. The obtained results show that by varying pH values, temperature and duration, the process the hydrolysis can be optimised by observing the content of free amino nitrogen. It has been established that the optimum conditions for free amino nitrogen formulation during hydrolysis catalysed by sulphuric acid are pH value 5.2 and temperature 52 deg C. As per hydrolysis catalysed by lactic acid, optimum conditions are pH value 6.0 and temperature 57 deg C. Satisfactory free amino nitrogen crops are also obtained by hydrolysis with lactic acid under pH values 5.0 and 5.5 in the temperature range 45-57 deg C. In both cases of hydrolysis, temperatures between 60-65 deg C do not enable satisfactory free amino nitrogen crops, which suggests possible inactivation of yeast protease.
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