Determination of the osmotic pressure of multicomponent solutions in the food industry

摘要

This paper is dedicated to the determination of the osmotic pressure of multicomponent solutions using aqueous food substances such as fruit and vegetable juices, whey, and lactose as examples. The determination of osmotic pressure as a critical parameter responsible for the efficiency of the membrane separation of multicomponent aqueous mineral-organic solutions is a problem of considerable current interest. An original method for the determination of the osmotic pressure of complex solutions has been developed. A relationship between the osmotic pressures of fruit and vegetable juices and whey and the concentration of lowmolecular-weight solutes (sugars and salt ions) in them has been revealed. A laboratory system for studying the reverse osmosis process has been developed. Experiments with fresh fruit and vegetable juices, curd whey, cheese whey, and lactose were carried out by a dynamic method with the use of a cellulose acetate reverse osmosis membrane with an asymmetric structure. The characteristics of the initial and final products after ultrafiltration are given. Based on the experimental data, the dependence of the osmotic pressure of fruit and vegetable juices, whey, and lactose on the concentration of dry solutes was plotted. The experimental results are discussed.