Change of anthocyanins content during production of jam from different species of fruit

Abstract

Anthocyanins represent soluble pigments. From them comes the red, blue and purple color of fruit. Anthocyanins are very easily degraded by heat treatment, which can have a major impact on the color quality and nutritional characteristics of the finished product. In order to determine how the heat treatment affects the content of the anthocyanins, jams were produced from peach and two varieties of raspberry. The jams were produced by boiling the prepared fruits, in open stainless steel vats on direct fire, under atmospheric pressure, temperature of ≈ 100 °C, for a period of 15 minutes. As sweeteners were used: sucrose, fructose, sorbitol and agave syrup. The analysis of anthocyanins was carried out on fresh fruits and obtained jams (spectrophotometrically at pH differential method with UV-Vis spectrophotometer). The research was repeated three times, for a period of three years. The values obtained for the average content of anthocyanins in jams (8.49 - 27.96 mg CGE/100 g FW) are lower compared to the established values in fresh fruits (18.45 - 108.43 mg CGE/100 g FW). Based on the results obtained, it can be concluded that with this method of heat treatment of the fruit (high temperature, presence of oxygen and light) part of the anthocyanins present in the fruits are lost during the processing. The obtained jams still possess the required quality in accordance with the standards.