豆豉纯种发酵过程中蛋白水解物与黑色素形成的关系

Relationship between Protein Hydrolysate and the Formation of Melanin during Pure-breed Fermentation of Douchi

由于豆豉传统自然发酵过程中微生物区系复杂,深入分析豆豉蛋白水解物与黑色素形成的关系存在一定难度,本试验以毛霉型豆豉自然发酵过程中四种主要毛霉(总状毛霉PR9.00140、雅致毛霉PR9.00018、腐乳毛霉PR9.00148和五通桥毛霉PR9.00151)为发酵菌种,通过分析豆豉纯种发酵过程中颜色变化和各种蛋白水解产物含量的变化趋势的关系,得出三种蛋白水解产物与颜色的相关性依次为多肽>游离氨基酸>大分子可溶性蛋白,其中多肽和游离氨基酸含量变化与豆豉颜色变化高度相关。对豆豉纯种发酵过程中各个相对分子质量段多肽的含量变化与豆豉颜色变化相关性分析表明:相对分子质量为500~200 u的多肽更多的参与了豆豉黑色素的形成。因此,本研究结果为完善豆豉质量控制与评价体系以及豆豉快速生产工艺的研发构建奠定了理论基础。

The complex microbial flora during traditional fermentation of douchi makes it a challenge to conduct in-depth analysis of the correlation between douchi protein hydrolysate and the formation of melanin. In this study, four main Mucor species from naturally Mucor-fermented douchi, namely Mucor racemosa PR9.00140, Actinomucor elegans PR9.00018, Mocor sufu PR9.00148, and Mucor wutongqiao PR9.00151, were used and the correlation between changes in the content of protein hydrolysates and color of douchi during pure-breed fermentation was studied. The results showed that the degree of correlation between three protein hydrolysates and color was in the following order: polypeptides > free amino acids > macromolecular soluble proteins, while the changes in the content of polypeptides and free amino acids significantly correlated with changes in the douchi color. The correlation evulation between polypeptides in different relative molecular mass ranges and color change of douchi during pure-breed fermentation of douchi indicated that polypeptides with a relative mass of 500 to 200 were more involved in the formation of melanin. Therefore, these results provide data for the development of improved quality control and evaluation system as well as rapid production of douchi.