title: Preparation and characterization of gellan gum microspheres containing a cold-adapted β-galactosidase from Rahnella sp. R3.
abstract: R-β-Gal is a cold-adapted β-galactosidase that is able to hydrolyze lactose and has the potential to produce low-lactose or lactose-free dairy products at low temperatures (4°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-β-Gal was encapsulated in gellan gum by injecting an aqueous solution into two different hardening solutions (10mM CaCl2or 10mM MgCl2). Enzyme characteristics of both free and encapsulated R-β-Gal were carried out, and the different effects of two cations were investigated. R-β-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-β-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.
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, 214122 Wuxi, China; US Department of Agriculture, Agriculture Research Service, Pacific West Area, Western Regional Research Center, Albany, CA 94710, USA. Electronic address: yilin58299@163.com.
authors.forename: Yuting
authors.initials: Y
authors.lastname: Fan
authors.affiliation: College of Chemistry and Environmental Engineering, Shenzhen University, 518060 Shenzhen, China.
authors.forename: Jiang
authors.initials: J
authors.lastname: Yi
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, 214122 Wuxi, China.
authors.forename: Xiao
authors.initials: X
authors.lastname: Hua
authors.affiliation: US Department of Agriculture, Agriculture Research Service, Pacific West Area, Western Regional Research Center, Albany, CA 94710, USA.
authors.forename: Yuzhu
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, 214122 Wuxi, China. Electronic address: yrj@jiangnan.edu.cn.
authors.forename: Ruijin
authors.initials: R
authors.lastname: Yang
mesh_terms: D003080:Cold Temperature; D008863:Microspheres; D011135:Polysaccharides, Bacterial / Q000737:chemistry*; D020638:Rahnella / Q000201:enzymology*; D001616:beta-Galactosidase / Q000378:metabolism*
chemical_list: D011135:Polysaccharides, Bacterial; C048288:gellan gum; D001616:beta-Galactosidase
keywords: Cold-adapted R-β-Gal; Encapsulation; Gellan gum; Hydrogel beads