Preparation and characterization of gellan gum microspheres containing a cold-adapted β-galactosidase from Rahnella sp R3

R-beta-Gal is a cold-adapted beta-galactosidase that is able to hydrolyze lactose and has the potential to produce low-lactose or lactose-free dairy products at low temperatures (4 degrees C). Cold-adapted enzymes unfold at moderate temperatures due to the lower intramolecular stabilizing interactions necessary for flexibility at low temperatures. To increase stability and usage-performance, R-beta-Gal was encapsulated in gellan gum by injecting an aqueous solution into two different hardening solutions (10mM CaCl2 or 10mM MgCl2). Enzyme characteristics of both free and encapsulated R-beta-Gal were carried out, and the different effects of two cations were investigated. R-beta-Gal showed better thermal and pH stability after encapsulation. Ca2+ gels had higher encapsulation efficiency (71.4%) than Mg2+ (66.7%) gels, and Ca2+ formed larger inner and surface pores. R-beta-Gal was released from.the Ca2+ hydrogel beads more rapidly than the Mg2+ hydrogels during storage in aqueous solution due to the larger inner/surface pores of the matrix. (C) 2017 Elsevier Ltd. All rights reserved.