The effect of moderate pulsed electric fields on autolysis ofSaccharomyces cerevisiaeand the amino acid content in autolysates

摘要

The effect of moderate pulsed electric fields (MPEF) strength on autolysis ofSaccharomyces cerevisiaewas evaluated in this study. After exposure to MPEF with intensity of 7 kV cm(-1)for 4 ms, the integrity of the cell wall was obviously destroyed and the inactivation ofS. cerevisiaereached 99.43%. During the subsequent 42-h autolysis process, the release of free alpha-amino nitrogen of MPEF-treated cells, as well as extracellular protease activity, was significantly (P < 0.05) higher than that of untreated cells. Moreover, exposure to 7 kV cm(-1)led to an increase of the total amino acid of 149.36%. In particular, the content of aspartic acid and glutamic acid which are important umami flavour precursors increased by 232.55% and 209.40%, respectively. These results indicate that MPEF will be an effective method to accelerate autolysis ofS. cerevisiaefor obtaining high-quality yeast extract as flavour enhancers and nutrition supplements.

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