DRYING KINETICS OF WHEY PROTEIN SOLUTIONS AS A STRUCTURING COMPONENT FOR FRUIT AND BERRY-PROTEIN COMPOSITIONS

Abstract. The article is dedicated to the experimental study of drying kinetics in the "drop–vapor-gas environment" system for whey protein solutions as a structure-forming component capable of enhancing the efficiency of drying composite products based on fruit and berry raw materials using spray drying. The aim of the work was to study the dehydration kinetics of individual droplets of whey protein solutions in the "drop–vapor-gas environment" system within a flow of heated heat carrier. Materials and Methods. The study used solutions containing 5% and 10% dry matter, prepared by dissolving whey protein powder concentrate after ultrafiltration (WPC-UF) in water, according to “DSTU 4458:2005. Protein Milk Concentrates. Technical Specifications.” The research was conducted on an experimental setup designed to study the drying process of single droplets, approximately 1.5 mm in size, of liquid systems in a flow of heated heat carrier. Results: The research showed that for droplets of whey protein solutions with a higher content of dry matter (10%), increasing the temperature of the heat carrier from 140°C to 180°C results in a 15% reduction in overall drying time compared to a 5% solution, under conditions of densification and strengthening of the structure of the dried particles. It was experimentally established that the main factor influencing the drying efficiency of whey protein solution droplets (or fruit compositions with it) is the content of dry matter (proteins). For a solution with a higher dry matter content (10%), regardless of the drying temperature, there is a significant reduction in the heating rate of the droplets (in the crust formation stage - 3 times compared to a 5% solution) and correspondingly high values of relative drying time to the point kr. 3 (≥0.8), which proves the ability of whey proteins to dry to a free-flowing powder state with low final moisture content.