Water activity in the products with intermediate moisture

The value Aw correlates with microbiological and physical-chemical processes, and its meaning and changes allow forecast foods stability, especially at storage. Three batches of concentrated whole milk with sugar filled in metallic cans № 7 were put for storing. Control batch was without dehydroquercetine and two experimental batches contained dehydroquercetine in the quantities 0,02 and 0,04 % of the fat mass in the product. The working program of the study included measuring of water activity after 6, 12, 15, 18, 21, 24 and 29 months of storing and comparing of the data received with established earlier threshold meanings. Before putting for storage the Aw values of all samples were in the range of 0,810-0,840 established for whole concentrated milk with sugar as for a product with intermediate moisture. In the course of further stages of control some small deviations have been noted with the shift to increasing. After 29 months of storage water activity in all samples was from 0,826 to 0,830. The results of the trials did not show noticeable deviations of the Aw meanings both from initial values and recommended ones. Comparing of the data received with threshold meanings that characterize intensity of product spoilage allows consider absence of development of undesired biochemical processes in all the samples studied substantiated. No considerable dynamics of the water activity index in the range from 0,820 (beginning of the study) to 0,830 (end of the study) was confirmed at controlled terms of storage, that ensured together with some other factors high keepability of the product studied during 29 months practically without changes of the standardized organoleptic and physical-chemical properties.

water activity, food products, products with intermediate moisture, canned milks, long storage