Study On Extraction And Purification Of Soybean Peptides By Solid-state Fermentation Of Soybean Meal

Soybean peptides are separated and extracted from the soy protein meal or soybean protein isolate, which is hydrolysised by protease or microbial fermentation. These are mainly small molecule peptide-based, it also contains a small amount of free amino acids, sugars and inorganic salts and other ingredients. The protein content of soybean peptide is about 85% , its amino acid composition are the same as soy protein, essential amino acids are balance and abundant. Because soybean peptide has many good physical and chemical properties and physiological functions, in many areas has been widely used. With functional properties and nutritional value of soybean peptide are deepen understanding, more and more experts began to study the production of fermented soybean peptide, but solid-state fermentation of soybean peptide is less.To make up for the lack of production of soybean peptides by protease hydrolysis and liquid fermentation method. Through processes like the extraction, desugar, bleaching, and desalination and so on, the subject has established a soybean peptides production process by solid-state fermentation of soybean meal. The process characterized by its fermentation capacity, yield, low cost open up new way for soybean peptides production. The main results are as follows:Extraction: Study on the effect with different extraction solvent to extract peptides, and ultimately select the hydrochloric acid as extracting agent. Then the single factor experiments and orthogonal test were studied to determine the optimal extraction conditions for the extraction time is 30min, extraction temperature 50℃, extraction agent (hydrochloric acid) concentration of 0.5mol / L. Peptide extraction rate was 48.5%Bleaching: Study on the effect with different bleaching agent, and ultimately select powdered activated carbon as bleaching agent. Then the single factor experiments and orthogonal test were studied to determine the optimum conditions for powdered activated carbon dosage of 1.5%, temperature 30℃, pH2.5, bleaching time 2.0h. The bleaching rate was 80.6%and the loss rate of peptide was 9.28% in the process of bleaching.Desugar: In this study, we use ion-exchange method to remove sugar, through the optimization of the adsorption and desorption process, and use pH2.5-12.5 elution buffer to desorpt, desugared rate reached 63.09%, while recovery of peptides 53.93%.The final recovery rate of soybean peptide was 23.72% and the purity was 85.5%, in line with the standards of soybean peptide powder (≧ 80%).