17-5 |
Opportunities with whey proteins as microencapsulating agents |
M. ROSENBERG, Dept. of Food Science & Technology, Univ. of California, Davis, 1 Shields Ave., 250-A Cruess Hall, Davis, CA 95616 Microencapsulation provides unique opportunities for protecting sensitive ingredients against deterioration or loss, pending consumption and for delivering bio-active compounds, nutrients and nutraceuticals. A need to introduce new, highly functional GRAS, microencapsulating agents exists. During the last decade we’ve investigated and discovered the functionality of whey proteins as microencapsulating agents for both water-soluble and water-insoluble microcapsules designed for food and pharmaceutical applications. Whey proteins exhibit unique functionality as wall materials for encapsulation of lipids (up to 75% w/w) and the layer of whey proteins adsorbed at the O/W interface provide sensitive lipids with long-term oxidative stability. This type of functionality has been further extended in developing highly functional composite microcapsules consisting of whey protein-coated lipid droplets embedded in wall systems consisting of wall solids with poor encapsulating properties. Wall systems consisting of whey proteins or blends of the latter with carbohydrates allow attaining high retention of volatiles during microencapsulation by spray drying and thus provide means to prepare water-soluble capsules containing a high load of flavor and aroma compounds. In highlighting the emulsification and heat-induced gelation properties of whey proteins, an array of different water-insoluble microcapsules and microspheres, for controlled- and/or sustained core release applications, can be prepared. Additionally, for pharmaceutical applications, whey proteins can be used in preparing chemically-cross-linked microcapsules containing water-soluble or water-insoluble pharmaceuticals. The rate of core release from these capsules, into either gastric or intestinal fluid, is diffusion controlled, and can be modulated by adjusting the cross-linking density and composition of the wall matrices. The physico-chemical properties of whey proteins provide unique opportunities for developing micro-porous microcapsules for the entrapment of bio-active compounds and microorganisms. The physico-chemical properties and especially the microencapsulating properties of whey proteins allow positioning these milk constituents as functional compounds in food and pharmaceutical value-added applications.
Session 17, Advances in microencapsulation technologies & applications in the food industry
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