Osmotic dehydration of berries: study of mass transfer parameters

Abstract

Osmotic dehydration, due to its advantages related to energy and quality, is gaining popularity as an additional stage of processing in the chain of complex processing of products. As a rule, osmotic dehydration is a slow process, so there is a need for additional methods to increase mass transfer without adversely affecting the quality of the product. This has provided the necessary motivation for many recent achievements in the field. Minimal processing methods, such as osmodehydration, find a significant place in the processing industry to increase the shelf life of fruit and berry raw materials. The overall efficiency of the process is determined by the process parameters affecting the phenomenon of mass transfer. Therefore, in this work the parameters of mass transfer in osmotic dehydration of berry raw materials: strawberry, raspberry, blackcurrant, BlackBerry are studied. The process of mass transfer has been modeled effectively, as evidenced by the results obtained. Berries, previously dehydrated at 70°Brix solution of sucrose, have the cryoscopy temperature lower (-1.7°C)–(-4.8°C), dehydrated at 60°Brix solution of sucrose from (-1.1°C) to (-2,6°C).The number of crystallized water in berries, dehydrated in 60°Brix solution of sucrose made up from 8.6–10.1 %, and in 70°Brix solution from a 13.9–12.9 %.The amount of frozen water in berries, dehydrated 70 ° Brix sucrose solution from 7.5–40.4%, dehydrated 60°Brix sucrose solution from 2.3–10.1%. Reducing the activity of water in berries treated with 70°Brix solution was 2.8–0.8 %, 60°Brix sucrose solution from 1.4–0.3%. The obtained data show that due to osmotic dehydration of berries with a solution of sucrose, followed by freezing, the activity of water decreases, which allows extending the shelf life and limits the access of microorganisms to growth in the environment.