SURFACE-PROPERTIES OF THE FAT GLOBULE IN TREATED CREAMS

Surface properties and susceptibility to lipolysis by a generic lipase were studied on raw cream, pasteurized cream and UHT-treated, homogen ized cream. Heat treatments did not modify extensively the structure o f the fat globule membrane, either in terms of its surface properties or of the nature of the associated proteins. Homogenization of cream r esulted in markedly increased susceptibility to the lipolytic action o f added enzymes, and was accompanied by extensive modifications of the surface properties. The protein composition of the milk fat globule m embrane in treated cream was different from that reported when cream w as isolated from treated milk. Attempts at discriminating commercial c reams on the basis of lipolysis and surface hydrophobicity indicated t hat measuring the susceptibility to lipolytic action could discriminat e pasteurized, non-homogenized cream from UHT-treated, homogenized cre am, while estimating surface properties did not allow such differentia tion. (C) 1997 Elsevier Science Ltd. All rights reserved.