Extraction Of Oligosaccharides From Soybean Whey And Its Modification By Enzyme

Soybean oligosaccharides include functional factors (raffinose arid stachyose )and nonunctional factor(sucrose). Commercial products from soybean oligosaccharides in China market have low content of oligosaccharides, about 30~40%. It was investigated In the study that soybean oligosaccharides were extracted from the soybean whey, and modified by enzymes to enhance its functional oligosaccharides.Soybean whey protein was precipitated by the method of acid, metal salt and heating. The optimum technological parameter is pH4. 3, CaCl, concentration 3?%,80-~---90~ of heating temperature, 20mm of heating time. The protein precipitated rate was 85. 20%. The soybean oligosaccharides retained rate was 91.24%.The ultrafiltration pressure was 3.0 4.Spsi, ultrafiltration temperature ~ and the molecular weight of ultrfiltration membrane was 10000. The soybean protein block rate was 87. 32%, and soybean oligosaccharides block rate 8. 91%.An Aspergil]us. oryzae which can produce P ---fructofuranosidase, EC 3. 4. 1. 26 of high enzymayic activity was examined from two kinds Aspergi]]us. oryzaes and one Candida gui]liennondii. The optimum culture condition is 95OOh at 300C, and the culture medium is wheat bran and soybean whey (1:0.9) with 3% sucrose. The enzyme had stronger transfer activity and wider acceptor, such as L梐rabinose, L梤hamnose, maltose, raffinose and sucrose. The enzyme solution was concentrated 2. 5 times by alcohol. The characters of P ructofuranosidase are (i) the optimum temperature of Pructofuranosidase was 35---450C, and the P ructofuranosidase was stable below 400C; (2) the optimum pH of P ructofurariosidase was 7----9, and the P ructofuranosidase was stable between pH5 and pH9; (3) the P D?fructofuranosidase was activated by Ag~ K~. Zn2and Hg2? (4) the P D?fructofuranosidase was inactivated by glucose~ mannose.. maltose and rhamnose, and the enzyme was activated by melezitose: (5) the enzyme solution can be preserved for two months at 40C; (6) the K,, of P ructofuranosidase wascan be preserved for two months at 4~C; (6) the K. of P 桪梖ructofuranosidasewas 1. 7812mmo1/L, and the Michaelis equation was ?~7. 0598/lW?-?0. 2523x 1ff . the optimum enzymatic synthesis of fruto梠ligosaccharide usingsucrose as donor and acceptor was pH 3. 5, 35XZ(reaction temperature) ,2.7~i mol/min. ~ (enzyme concentration) and 8 hours (react ion time ). The yiel. of fructo梠ligosaccharides was 54. 27%. When the reaction condition was used in fructo梠ligosaccharides synthesis of soybean oligosaccharides syrup, 61% sucrose was transferred into fructo梠ligaosaccharides , and the oligosaccharides content were increased from 38. 98% to 54. 27%.The acid and heat stable of enzymatic conversation soybean oligosaccharides were (1) the fructo梠ligaosaccharides was heating stable at pH 6----8: (2) stachyose was heating stable at pH>4 (3) raffinose was heating stable at pH3挆Modified soybean oligosacharides was proven to be healthy safety wlih Ames experiment, medullary eosinophilic erythrocyte trial, deformation of testicular chromesome in rats.Doctorate Student:Ma YingMajor:Animal Food ScienceTutor:Prof. Luo Gheng-xiang...