Phase equilibria for food product and process design

Phase equilibria play a very important role in food technology. Most foods are multiphase dispersions either structured by nature (e.g., plant or anim al tissues) or by man. Sensory properties are strongly dependent on the mic ro structure and how this breaks down during mastication. Flavor perception , particularly aroma, is governed by the way aroma molecules are distribute d over various phases. Many food manufacturing processes aim to create desi red microstructures where crystals (ice, fat), droplets (oil, aqueous solut ions of biopolymers), air bubbles form phase separated networks with soft s olid properties or other rheological characteristics essential to the food product. Other processes aim at concentrating or separating volatile aroma compounds from raw materials for later use in final product manufacture. In this presentation we will discuss some examples where phase behavior plays a key role to obtain quality food products: solid/liquid phase equilibria of triglycerides; controlled microstructure formation in aqueous mixed biop olymer systems; liquid crystalline phases as microstructure forming agents; aroma retention/release from food products. In each example, we will try t o show the importance of phase equilibrium thermodynamics and to indicate c hallenges for research. (C) 1999 Elsevier Science B.V. All rights reserved.