KINETIC CHARACTERISTICS OF DRYING DROPLETS OF APPLE JUICE AND COMPOSITIONS BASED ON THEM WITH MILK PROTEINS

Abstract

Recently, the demand for concentrates and dry powders from natural fruit and berry raw materials has been growing in the food industry. Spray drying is a method that is widely used to increase the shelf life of food products. However, obtaining dry concentrates from clarified, unclarified juices, as well as juices with pulp, by the spraying method has certain difficulties. This is due to the fact that apple juices and purees contain a complex of organic acids (malic, citric, etc.) in combination with a large number of simple carbohydrates. These substances are the main factors of the viscoplastic state of the dried particles in the heated air in the drying chamber. Thermoplastic (adhesive) properties of the material to be dried in the chamber of the spray dryer and hygroscopic in the state of dried powders complicate the conditions for their timely removal from the chamber, separation, unloading, and storage. As a result, the presence of such properties worsens the organoleptic and physicochemical characteristics of dry powders, reduces product yield, and also complicates the operating conditions of drying equipment. The use of structuring additives of various types, which include protein products of various origins, contributes to the improvement of drying conditions. The aim of the work was to study the kinetic characteristics of dehydration of drops of apple juice and compositions with milk proteins in order to determine the feasibility of their use as structuring additives for the preparation of powdered health products based on apple juice by spraying. The research results showed the expediency of using a complex of skim milk proteins and whey protein concentrate as structuring additives. It has been proven that their use improves the structuring and vapor-conducting properties of the material during drying, due to which it is possible to obtain powder products with minimal final moisture while preserving valuable bioactive components.