Abstract:

The hollow globular chitosan was made by injecting mixture of 15% NaOH and 30% CH3OH into 25% chitosan solution. Thenβ-glucosidase was immobilized by the coupling effect of 4% gluluraldehyde and the hollow globular chitosan. It was found that the optimum reaction temperature and pH and relative activity of immobilized β-glucosidase are 68 ℃, 4.0 and 87.9%, respectively. The soybean isoflavone glucoside was firstly extracted with a yield of 4.0 mg/g from soybean meal by 60% alcohol at 50 ℃, and then hydrolyzed by immobilizedβ-glucosidase at 70 ℃ for 1 h. After treatments of ultrafiltration and immobilized yeast fermentation, finally soybean isoflavone with the purity of 94% was obtained.

Key words: immobilized β-glucosidase, soybean isoflavone, chitosan