The influence of freeze drying on the quality indicators of potato tubers

¹ Russian Potato Research Centre, Moscow Region, Russian Federation
² Russian State Agrarian University - Moscow Timiryazev Agricultural Academy, Moscow, Russian Federation

^* Corresponding author: alexman80@list.ru

Abstract

In Russia, there is an active development of the Arctic, the Northern regions, the supply of which with food is difficult. The production and supply of freeze-dried vegetables and potatoes is an important task, given that the need for potatoes in terms of nutritional standards is higher than all other vegetables combined, and cargo deliveries are by weight, reducing the weight of the supplied potatoes by four times, taking into account the increase in shelf life by dozens of times and resistance of the freeze-dried product to frost, this is an extremely important area of research. The purpose of the research is to study the quality indicators before and after freeze-drying of potato tubers of domestic and foreign varieties, including varieties with pigmented pulp and skin. The measurements were carried out in the laboratory of the A.G. Lorch” using standard techniques. According to the results of biochemical analysis, the total content of alcohol-soluble flavonoids in terms of quercetin in tubers was 0.08-1.13 mg/g in wet weight, in freeze-dried samples - 0.22-1.46 mg/g in dry weight. The content of low molecular weight antioxidants in fresh potato pulp varied from 0.12 to 1.92 mg/g wet weight, the total content of phenolic compounds in sublimated samples varied from 0.55 to 4.63 mg/g dry weight in gallic acid equivalents. A significant advantage of this drying is the ability to restore freeze-dried potatoes in 60 minutes. The conducted studies confirm that the content of antioxidants in different varieties of potatoes is different and remains after freeze-drying, which makes it possible to select potato varieties for creating healthy food products. Freeze drying of vegetables is an energy-intensive operation. However, according to domestic and foreign manufacturers of freeze-dried products on an industrial scale, the high quality of finished products, the absence of costs for creating a special temperature and humidity storage regime, and a low specific gravity offset the costs of drying.