Влияние сублимационной сушки на качественные показатели клубней картофеля

Abstract

Freeze-dried vegetable production is intensively developing due to its advantages - a four-time decrease in the weight of supplied freeze-dried potatoes, increased shelf life by dozens of times, and the resistance of freeze-dried products to temperature fluctuations. To study the quality indicators of potato tubers before freeze-drying and after it using standard techniques, the authors analyzed domestic and foreign varieties including those with pigmented flesh and peel. Freeze-drying of potato tubers was carried out in the vacuum-sublimation machine USS‑5 in two stages: rapid freezing of 2 to 3 cm thick sample plates to -30°C during 4 h and heating to +50°C during 2.5 h. Raw potato tubers and freeze-dried samples were tested for antioxidant, phenolic and flavonoid content using standard methods. The results of biochemical analysis showed the total content of alcoholsoluble flavonoids in fresh potato pulp in recalculation on quercetin 0.08 to 1.13 mg/g raw weight, in freeze-dried samples - 0.22 to 1.46 mg/g dry weight; total content of low-molecular antioxidants in fresh pulp from 0.12 to 1.92 mg/g raw weight, phenolic compounds in freeze-dried samples from 0.55 to 4.63 mg/g dry weight in gallic acid equivalents. The study also focused on the determination of the moisture absorption level of freeze-dried potato tuber slices. Moisture saturation of freeze-dried potato slices when immersed in room temperature water occurred within 60 min. Freeze drying had no effect on the antioxidant content of the potato tubers. Therefore, this method can be used to produce healthy foods.