Abstract
The mode of freezing vacuum packed vegetable mixtures with preliminary light freezing on the grid and final freezing on the metal plate was studied. The advantages of this method consist in minimization of a product contamination by pathogenic microorganisms during packaging as well as in increasing a product shelf life due to a packet evacuation. The experimental curves of vegetable mixture freezing were plotted. The duration of the process (113 min) and its speed (1.25 cm/h) were identified. A graphanalytic thermal method of calculation of a vegetable mixture freezing duration for a combined freezing method was offered. The results obtained are as follows: the thickness of the layer frozen in the cold air flow is 5.7 mm, on the metal plate - 19.3 mm. The process duration defined as a result of the theoretical calculation was 111 minutes that showed the correctness of the calculation application. An energy efficiency of the process in the range of air motion speeds of 1-3 m/s in a quickfreezing chamber was analyzed. During experiment the air flow speed was 1.5 m/s. It was optimal for a combined freezing method that was hereafter proved by the energetic analysis. The combined method of freezing and the graphanalytic method of calculation of the process duration may be used in fruitvegetable industry.
Open Access
Access granted
