Removal of Raffinose Family Oligosaccharides from Soymilk by alpha-Galactosidase Immobilized on Sepabeads EC-EA and Sepabeads EC-HA

Enzymatic hydrolysis of raffinose family oligosaccharides (RFOs), mainly raffinose and stachyose, into digestible sugars improves the nutritional value of soybean and soymilk. alpha-Galactosidases have been widely employed for the degradation of RFOs in industrial food applications. In the present study, alpha-galactosidase was immobilized on Sepabeads EC-EA and Sepabeads EC-HA by direct covalent attachment and also by adsorbtion/crosslinking methods by using glutaraldehyde chemistry. The covalently immobilized enzyme on Sepabeads EC-HA completely hydrolyzed both raffinose and stachyose for 24 h. The adsorbed/ crosslinked enzyme on Sepabeads EC-HA hydrolyzed the stachyose and raffinose with 100 and 88.6% degrees at the same time, respectively. The results suggested that the covalently immobilized enzyme on Sepabeads EC-HA is more efficient in the degradation of RFOs. Therefore, this form of enzyme may be a good candidate for removing of RFOs found in many products of the food industry.