酵母自溶动力学及其影响因素研究(Ⅰ)——酵母细胞自溶生物学研究

STUDIES ON DYNAMICS OF YEAST AUTOLYSIS AND INFLUENCE FACTORS (Ⅰ)autolysis biology of Saccharomyces cerevisiae

对啤酒酵母细胞自溶的动力学研究结果表明,在55℃,pH5. 5的醋酸钠缓冲液中,酵母自溶诱导期约为1. 85h;细胞内贮糖原降解最快,蛋白质次之,核酸降解速率最慢。酵母细胞生物大分子的降解自溶存在显著的正协同效应,酵母生理状态对自溶液的氨基酸组份影响极显著(P<0. 01) 。随培养时间延长,相应自溶液中的必需氨基酸、鲜味及苦味氨基酸比例显著增加,因而自溶液的鲜味增浓,营养效价提高,但苦味亦上升。

The autolysis biology of Saccharomyces cerevisiae is studied at 55℃ in apH5. 5 sodium acetate buffer.The induction phase of yeast cell autolysis is about1. 85h.Glycogenolysis carries out most rapidly,and its half time(t_(0. 5) )is only1. 48h.Proteolysis proceeds faster than the lysis of nucleic acid,t_(0. 5) of nucleic aciddegradation is 12. 38h,which can be taken as an important parameter for optimizationof yeast autolysis conditions.The degradation of biomacromolecules in yeast cell existswith significantly positive synergistic effects.The yeast extract amino acid compositionvaries with the physiological longevity of yeast cell.With the delay of culture period,the mole fractions of necessary amino acids,and those with delicate and bitter taste in-creases obviously,while the content of Pro,Arg,Ala,Cys decreases.