The effect of low-temperature processing of semi-finished potatoes on the ascorbic acid content

Abstract

In Russia, only 2% of grown potatoes are processed, while in Western countries this figure exceeds 50%. In the food industry the use of potatoes in processed form (various semifinished products) has a number of advantages as compared to fresh potatoes. It is established that the range of processed potato products is expanding every year, however, one of the most popular types of semi-finished products from potatoes are those subjected to low-temperature processing. In this regard, the change in the content of ascorbic acid in semi-finished potato products during freezing and storage was studied. After examining the chemical composition of five varieties of potatoes grown in the Kemerovo region the “Rikeya” variety was selected. Freezing of the potatoes was carried out at temperatures of -24ºC and -40ºC with natural, as well as forced convection with an air velocity of 1.25 and 2.5 m/s. The resulting frozen semifinished products were stored for 25 days at temperatures of -12ºC, -18ºC, -24ºC. It was found that the temperature of freezing and storage, as well as air velocity during freezing, significantly affect the preservation of vitamin C in semi-finished potatoes. The determining factor contributing to the preservation of the processed potatoes’ quality is the temperature regimes of freezing and storage – the smaller the difference of these temperatures, the less the loss of ascorbic acid.