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 animal tissues) or by man. Sensory properties are strongly dependent on the micro structure and how this breaks down during mastication. Flavor perception, particularly aroma, is governed by the way aroma molecules are distributed over various phases. Many food manufacturing processes aim to create desired microstructures where crystals (ice, fat), droplets (oil, aqueous solutions of biopolymers), air bubbles form phase separated networks with soft solid 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 biopolymer systems; liquid crystalline phases as microstructure forming agents; aroma retention/release from food products. In each example, we will try to show the importance of phase equilibrium thermodynamics and to indicate challenges for research.