Effect of Processing Methods and Storage Time on the Content of Ascorbic Acid in Berries

Abstract

The article presents the results of a study of the dynamics of the content of ascorbic acid in berries of black and red currants and raspberries during storage in a frozen form and during conservation of berries grated with sugar. As objects of research, we used two varieties of red currant, black currant and raspberry. The ascorbic acid content served as a marker of the berry quality during storage. The analysis of ascorbic acid was carried out by the iodometric method according to the standard method. It was found that immediately after freezing, the loss of ascorbic acid is from 6 to 20%, which is significantly less than when grinding with sugar (65–97%). The decrease in the content of ascorbic acid in berries during storage occurs unevenly and after 6 months the concentration stabilizes. When storing frozen berries, additional losses of vitamin C in red and black currants averaged 83%, and in raspberries – 66%. During storage of berry puree, additional losses were 32% for red and black currants, and 89% for raspberries. The best preservation of ascorbic acid was observed when stored frozen – in experiments with black currants, while storing berry puree – in experiments with red currants.