Studies On The Peptide Produced By Hydrolysis Of Isolated Soybean Protein And It's Applications In Beverage

The appropriate enzyme was selected with the parameter of hydrolysis degree in order to improve the functional quality of soybean protein and its applications in foods. It showed that hydrolyzed polypeptide contains lots of nutrients and can accelerate growth of microorganism. Through the analysis of soybean polypeptide molecular weight distribution, it was illustrated that molecular distributions is continuous. Nutritional beverage containing soybean polypeptide was studied by debittering and desalting.Isolate soybean protein (ISP) was used as the substrate to be hydrolyzed with Alcalase, papaya protease, Neutrase, pepsin and trypsin under the suitable conditions after heating, it showed that the hydrolysis degree of soybean protein was high with Alcalase. The appropriate condition in hydrolyzing soybean protein were: temperature was 60 C, pH was 9, concentration of substrate was 2% by the designing of third-factor D-superior saturation.When isolated soybean protein was hydrolyzed in different time, the best hydrolysis time was 5 hours by with the parameters of hydrolyzed degree and reclaimation ratio.Hydrolysates from different time: 3 hours, 4 hours,5 hours, 6 hours were used as the nitrogen source of MRS, Ml7 medium, it was found that the hydrolysates were nutrtious and beneficial to microorganism growth..Components and characteristics were studied after the above hydrolysates were dried and it was showed that the percentage of protein was 80%, with amino acids, moisture, inorganic salt and others. The solubility was 90% and viscosity was stable, which was suitable in egg white drinking and high protein jelly. Stabilization was good and bitterness cope was 0.40%.Molecular weight distribution of hydrolysates was analyzed through ultra-filtration and sephadex G-25 layer, it was showed that the main molecular weight distribution of soybean polypeptide was below 1000. It showed that the peptide distribution and hydrolyzation reaction were continuous.The appropriate reaction conditions were active carbon / protein = 0.1 -0.2 /L(w/v), temperature=50-55 C, pH=4-4.5 by mixing slowly hydrolysates with active carbon for 2 hours for debittering. If the above method was substituted with the mobile bed, the ratio of desalting was 12.3% and the salt concentration of the hydrolysates was about 0.46%.Nutritious beverage containing soybean peptide was produced through three factorsand three levels experiment design, it showed that the main factor that influence the sense organs assessing was in turn as: acid concentration> polypeptides of soybean concentration> stabilizer. The best formula of product was: sucrose 10.5%, concentrated orange 5%, acid 0.38%, Soybean polypeptide 1.0%, stabilizer 0.4%. The optimum sterilization time was 15min at 100 C. The nutritious beverage can be stored for 6 months with no ratting phenomenon.Liu wenhui, The Food Science Supervisor: Prof.zhang Lanwei...