STRUCTURAL-FUNCTIONAL AND WATER-HOLDING STUDIES OF BIOPOLYMERS IN LOW-FAT CONTENT SPREADS

Structural and textural properties of edible low-fat spreads were obta ined using various formulations of milk proteins, maltodextrins and no n-gelling agents (e.g. fibres). Dynamic oscillation measurements and c ompression tests suggest that buttermilk protein from spray-dried rete ntates obtained by ultrafiltration, and commercial Cerestar potato mal todextrin are the most efficient gelling agents with better plastic fa ilure. A dispersed system in such a composition can be referred to as a microheterogeneously phase-separated system with a presence of inhom ogeneities within one phase. Network studies establish that protein fo rms a continuous matrix. It is also supported that a substantial amoun t of the fat and at least part of the protein are in the dispersed pha se in the form of protein-fat aggregates, and any non-aggregated prote in is in the continuous aqueous phase. Branched maltodextrins and line ar nonaggregated fibre inclusions penetrate the continuous protein net work and these microheterogeneities may encourage plastic failure. Mod ification of the homogenisation regime can be employed to develop prod ucts with stress-strain relationships in the preferred range of specif ication and commercial application. (C) 1997 Academic Press Limited.