Microencapsulation of glucosyltransferase by ionic gelation

FABIANO J. CONTESINI; IBARGUREN, CAROLINA; AUDISIO, M. CARINA; SATO, HELIA H.; GROSSO, CARLOS

Dublin, Irlanda

Conferencia; XVI International Conference on Bioencapsulation; 2008

Bioencapsulation Research Group

Isomaltulose or palatinose® is a non-cariogenic sugar, naturally present in very small quantities in honey, sugar cane extract and other sugar-rich fluids. This alternative sugar is commercially obtained by the enzymatic conversion of sucrose catalyzed by glucosyltransferase. The isomaltulose shows physicochemical and organoleptic properties similar to those of sucrose and has a low glycemic index. The safety of isomaltulose has been comprehensively verified, resulting in its approval as human food (Lina et al., 1997), and it is widely used commercially as a sucrose substitute in foods, soft drinks and medicines. The use of enzyme immobilization techniques is well known to produce stable and reusable biocatalysts since a hydrogel matrix could protect the enzyme from environmental conditions such as pH, temperature, organic solvents and other compounds capable of inactivating them. The immobilized catalyst could also be handled more easily and recovered from the solution without difficulty (Derkavos et al., 1991). Within this framework, the microencapsulation by ionic gelation is straightforward and inexpensive. Pectins, which gelation mechanism is mainly governed by their degree of esterification (DE), are among the most widely studied ionic polysaccharides with useful and versatile properties in this application area. The addition of hydrophobic compounds such as lipids can improve the retention of the hydrophilic compounds used as core materials in these matrices. These microcapsules present high water content and low water solubility, and they can be produced in different sizes and shapes. In this work the microencapsulation of glucosyltransferase produced by the strain Erwinia sp. D12 was evaluated using low methoxyl pectin with or without fat mixture addition (butter milk plus oleic acid, 1:1) wet and freeze dried. Microparticles characterizations with respect to morphology, average size and enzymatic activity after 6 cycles of production of isomaltulose from sucrose solutions were evaluated.