| A procedure for producing small peptides by fermentation of cottonseed protein was developed，in the purpose of exploiting low-quality cottonseed meal with high performance. The technology of uncooked material fermentation was been used in the process. Research contents include：screening the effective microorganism，studying of fermentation procession conditions and detection of protein molecular.we also try secondary fermention and want to see the effection on the small peptide and free gossypol. The paper consists of four chapters.The first chapter ferment the cottonseed meel by lactobacllius plantarum，candida， bacillus subtilis and aspergillus niger.The results show that lactobacllius plantarum and candida do not have effection on production of small peptide but on free gossypol, especially for lactobacllius plantarum The bacillus subtilis and aspergillus niger have obvious influence on small peptide,especially for aspergillus niger.In the process of increasing small peptide, the free gossypol is also increasing.In the second chapter, influencing factors such as pH, temperature and time of fermentation were studied in order to establish a best condition to increase small peptide in cottonseed meal. The results showed that the influence factors sequence is temperature>time>PH the best condition for fermentation was30℃,36hours, pH4.5the content of small peptide can reached39.14%.In the third chaper, Tricine-SDS-PAGE method was used for peptides analysis. From electrophoretic bands, after fermentation,we see that there is no band of cottonseed meal.It show that the high molecular weight protein was decomposed into small peptide.In the last chaper, lactobacllius plantarum was used to decrease the free gossypol of cottonseed meal which was fermented by aspergillus niger.However,the result shows that the free gossypol was not decreased by lactobacllius plantarum but increaseing again the production of small peptide was increased to45.32%. |
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