Study On Melanin Formation Mechanism Involved Protein Hydrolysatein In The Rapid Production Of Melanin

Douchi is a traditional Chinese fermented food, which is under the action of microorganism in soybean, after a long time of natural fermentation, finally forming a unique quality and flavor of the food or condiment. Douchi has a high nutritional value, rich in soybean polypeptide, soybean isoflavone, oligosaccharide, melanin function active substance. Mucor fermented soybeans are the Chinese fermented Douchi edible the widest range of douchi, fermented Yongchuan as its representative, by people praise, it has been paid more and more attention. At present, research on Yongchuan Mucor fermented soybeans, mainly in the production process and functional components, research on its main color material melanin rarely reported. The deep relationship between protein and the formation of melanin, is not found. Melanin is the final products of Maillard reaction, the protein may be involved in Maillard reaction substrate as the object of study, exploration in the douchi melanin formation stage and the fast bean melanoma relationship.The four strains separated from traditional Yongchuan Douchi is Mucor racemosus, Actinomucor elegans, Wutongqiao Mucor Sufu Mucor and. In this paper, based on the four kinds of Mucor strain of pure fermentation, the soluble protein, soluble protein, polypeptide molecules, free amino acids in four kinds of protein hydrolysates as index, changes to the content in the fermentation process were analyzed, through the correlation fitting and color, determination of rapid forming stage in douchi melanin, the formation of protein hydrolysate species associated with black pigment. The molecular weight of the peptide segment of HPLC, analysis the main source of polypeptide changes, combined with the SDS-PAGE mapping analysis mainly involved in protein degradation of melanin formation. The polypeptide content and color matching, determine the melanin fast color formation stage, the molecular weight of the group to participate in the formation of melanin polypeptide. Add protease of Douchi in the post fermentation, effects of different proteases on the formation of melanin. The main conclusions are as follows:(1) The rapid forming stage in douchi melanin, protein degradation and color related peptide, amino acid, polypeptide and color the most correlation, the person coefficient is0.969**, a significant correlation (p<0.01). SDS-PAGE electrophoresis showed Mucor fermented soybeans in melanin rapid formation stage, acidic subunits of11S may be involved in one of the major protein degradation products of the rapid formation of melanin, some larger than98kDa molecular subunits and the molecular weight of60kDa,30kDa subunit, its degradation products may also be involved in the formation of melanin.(2)In four purebred Douchi fermentation process, the formation of protein hydrolysate and color is the most relevant polypeptides of500-200Da and the molecular weight of3000-1000Da,500-200Da and color the highest correlation.(3) The rapid formation of melanin in the stage of Douchi, Mucor secreted neutral protease and alkaline protease, neutral protease and alkaline protease has a promoting effect on the formation of melanin, and neutral protease plays the most important role. Alkaline protease producing plays a main role to the500-200Da peptide and3000-1000Da.Review the results of Mucor fermented soybeans, the molecular weight of500-200Da and3000-1OOODa polypeptides involved in the formation of melanin, in the fermentation process. In the black pigment fast formation stage, Mucor secreted neutral protease and alkaline protease by catalytic degradation of proteins,500-200Da and3000-1000Da polypeptides, providing substrate for the formation of melanin. In industrial production, can consider to add these two types of protease, control of Douchi fermentation process.