| Abstrakt: |
Every year, cultivation and areas under blueberry plantations are increasing. Blueberry (Vaccinium corymbosum L.) has gained popularity in the nutrition of the population of Ukraine due to its medicinal and prophylactic properties. Blueberry berries are processed for storage mainly by freezing, less often by drying. The latter is due to the long duration of the process, as low-temperature dehydration regimes are used and the presence of a wax coating on the skin of the berries. Wax prevents fresh blueberry berries from spoiling during storage. But it significantly hinders its processing. In addition, blueberries have a high moisture content of 81-87 %. Reducing humidity through dehydration reduces the activity of pathogenic microorganisms, increases safety and extends the shelf life of food products. At the same time, it leads to a change in taste qualities. In this direction, one of the key issues is an indicator that affects the structural properties of the product, the shelf life and depends on the nature and amount of components soluble in the aqueous phase of the product, as well as on the methods of processing raw materials, semi-finished products, etc. Accordingly, the value of the "water activity" indicator is decisive (aw), the value of which depends not only on the forming indicator of the product, but also on the development of microorganisms. On the basis of previously conducted studies of the influence of the pretreatment method on the kinetics of blueberry drying, depending on the different regime parameters of the heat carrier, the indicator of water activity of dried berries was determined for the first time. It is substantiated that the content of such compounds as protein, fatty substances, sugars, flavonoids, anthocyanins, color compounds, etc., affects the indicator of water activity. For the first time, the effect of mode parameters of the convective and combined heat carrier (infrared radiation treatment with simultaneous convection) at different temperatures of the heat carrier was revealed, which showed a change in the values of the coefficient of the water activity indicator for dried blueberries. The coefficients of the water activity indicator were calculated and the significant influence of the drying process on the quality of the finished product was shown. The obtained values of the coefficient of the water activity indicator can be used to evaluate the storage quality of dried blueberry berries and their powder. [ABSTRACT FROM AUTHOR] |
