The prospects for freezing of Jerusalem artichoke (<i>Helianthus tuberosus L.</i>) tubers
Jerusalem artichoke being rich in amino acid, its biochemical composition, and its large content of polysaccharides, inulin and pectin make this plant indispensable for the production highly effective medicines for treatment and prevention of different diseases. One of them is a functional coffee substitute for people suffering from diabetes and hypertension. The freezing of Jerusalem artichoke tubers (Leningrad variety) was analyzed. The process parameters were substantiated. The quality characteristics and changes in the frozen Jerusalem artichoke in the process of storage and the degree of freezing influence on the quality and the yield of coffee substitute were analyzed. The weight loss in the process of Jerusalem artichoke freezing at -22 °C was 5.33%, this figure increasing by an average of 2% per month during the storage (6 months). Such key indicators as the mass fraction of pectin and inulin also experienced a sharp decline during the period of storage - from 13.08% and 5.98% to 8.2% and 3.6% respectively. As the result of the experiments carried out at the cooling medium temperature of -35 °C the whole tubers were proved to be the most preferred form for freezing. The losses in shock freezing at -35 °C amounted to 1.13% by weight of raw materials. Data obtained in the analysis of raw materials and coffee substitute for 4 months show stable quality of shock frozen Jerusalem artichoke during the period, which allows us to recommend this method for raw materials keeping for 4-6 months.