绍兴腐乳发酵过程中蛋白质水解及其对成品白点影响的研究

Study on the hydrolysis of proteins in the process of Shaoxing sufu fermentation and the influence on white particles in products

研究了绍兴腐乳发酵过程中蛋白质水解与酪氨酸含量变化的规律,分析了不同发酵时间腐乳样品的氨基酸态氮、三氯乙酸-氮溶指数（TCA-NSI）、游离氨基酸、蛋白质水解度（DH）、酪氨酸含量及蛋白质分子量变化。结果表明：绍兴腐乳发酵过程中坯料中酪氨酸随着氨基酸态氮、TCA-NSI、游离氨基酸、DH的增加而增加;1～40d内主要是7S和11S蛋白质的分解,40d以后主要是小分子蛋白质的进一步分解。相关性分析表明,游离酪氨酸的含量与DH的Pearson相关系数最高。同时对成熟腐乳的研究发现有白点腐乳的TCA-NSI、DH和游离酪氨酸显著高于无白点腐乳,这表明了腐乳中白点的形成是由蛋白质过度水解造成的。本研究为绍兴腐乳白点的控制提供了参考。

The rules of the protein hydrolysis and the tyrosine content were studied. The changes of amino nitrogen ,TCA-soluble nitrogen index （TCA-NSI）,free amino acid, degree of hydrolysis （DH）,tyrosine and protein molecular weight were analyzed. Results showed that tyrosine increased with the increase of amino nitrogen,TCA-NSI,free amino acid,DH in pehtze during Shaoxing sufu fermentation. The mainly degraded proteins in the first 40 days were 7S and 11S proteins,while the mainly degraded substance after 40 days was low molecular protein. Correlation analysis indicated that the Pearson correlation coefficient of the content of free tyrosine and DH was higher than that of others. Besides this,the TCA-NSI,DH and free tyrosine were higher in sufu with white particles than those in sufu without white particles,so it could be concluded that the white particles in sufu were formed due to the excessive hydrolysis of proteins. This research could provide reference to control white particles in Shaoxing sufu.