固态发酵下酵母自溶的工艺优化

Optimization of yeast autolysis under solid-state fermentation conditions

摘要:

固态下酵母自溶可以有效促进菌体内多种活性物质的释放，进而提高酵母类产品的品质。通过优化自溶温度、自溶时间及自溶促进剂锌离子浓度以获得固态发酵下酵母自溶的最佳工艺，对固态发酵物料中游离氨基酸、可溶性蛋白、α-氨基氮含量和A260/A280等指标的分析来确定固态酵母自溶工艺条件，在此基础上以自溶温度40 ℃、50 ℃、55 ℃；作用时间12、18、24 h；锌离子添加浓度2、4、8 mg/kg设置L9(33)正交试验，进一步优化固态酵母自溶的工艺参数。结果表明酵母自溶的最佳工艺条件为：自溶温度55 ℃、作用时间18 h、锌离子浓度2 mg/kg，此时其可溶性蛋白含量可达9.31 mg/g、游离氨基酸14.36 mg/g、α-氨基氮10.16 μg/g、A260/A280为1.73。经工艺优化后，可显著提高酵母自溶产物可溶性蛋白、游离氨基酸和α-氨基氮的含量，从而明显提高了复合菌培养物的品质。

Abstract:

Yeast autolysis under solid-state fermentation can effectively promote the release of various active substances, thereby improving the quality of yeast products. The optimal process for yeast autolysis under solid-state fermentation was obtained by optimizing the autolysis temperature, autolysis time and the zinc ion concentration. We analyzed the indexes of free amino acid, soluble protein and α-amino nitrogen in the fermentation material, as well as A260/A280 ratio to determine yeast autolysis process conditions in the solid-state fermentation. On the basis of the obtained data, L9 (33) orthogonal test was designed to optimize the solid-state fermentation parameters for yeast autolysis: temperature at 40, 50 and 55 °C; time 12, 18 and 24 h; zinc ion concentration 2, 4 and 8 mg/kg. The optimum process conditions for yeast autolysis were: autolysis temperature 55 °C, time 18 h, zinc ion concentration 2 mg/kg, and soluble protein content reached 9.31 mg/g, free amino acid 14.36 mg/g, α-amino nitrogen 10.16 μg/g and A260/A280 1.73. After optimization of the process, the soluble protein, free amino acid and α-amino nitrogen contents of the yeast autolysis production can be significantly increased, thereby obviously improving the quality of the composite culture.