Analysis of the influence of low temperature on the change of physicochemical parameters of fruit and berry raw materials during storage

Abstract

A modern postulate of a healthy lifestyle is consuming products with a high content of natural physiologically valuable ingredients. These types of products include fruits and berries. However, the seasonality of their production makes it necessary to search for effective conservation methods that will not significantly change the physicochemical parameters. Considering that the most popular and advanced method is shock freezing, we have analyzed the influence of low temperatures on the quality characteristics of fruit and berry raw materials and the fractional composition of pectic substances. Due to the pluripotential properties, pectic substances determine the functional value of raw materials. As the research object we have chosen winter apple varieties such as Rennet Simirenko, Gloster, Granny Smith, Korey; stone fruits – cherry varieties such as Podbelskaya, Lyubskaya; cherry plum varieties such as Desertnaya and Kremen; berries - red currant varieties such as Natali and Nenaglyadnaya, black currant varieties such as Pamyat Lisavenko and Orloviya. The varieties of fruits and berries were chosen based on their regional prevalence in southern Russia. It has been established that the low-temperature storage of frozen fruit and berry raw materials decreases the weight ratio of dry solids (1.2 - 4.0%), sugars (4.0 - 9.0%) and pectic substances (4.8 - 24.9%). The titratable acid content increases. According to our findings, the fractional composition of pectic substances changed during low-temperature storage of berries, pomiferous and stone fruits. The fractional redistribution was presented in the form of reduction of protopectin and increase of soluble pectin in all studied berry samples. According to the research results, the functional properties are best preserved in berry raw materials.