JELLY-FORMING ABILITY OF PECTINS OF FRESH AND FROZEN RED CURRANT BERRIES

Red currant berries are characterized by high contents of pectin substances and an optimum combination of organic acids and sugars. Freezing is an efficient method of retaining high quality of raw material for a long time. The aim of this research is to study technological features of pectin in fresh and frozen berries of red currant and in jelly produced on their base. As a result of the studies it has been determined that berries of studied red currant varieties are characterized by high contents of pectin substances, their contents being slightly reduced in a process of low temperature freezing and storage, namely, by 4% on average within the varieties. At the same time the pectin in berries of red currant are highly etherificated because the degree of their methoxylation exceeds 50% in a majority of varieties (Bayana, Valentinovka, Vika, Dana, Dar Orla, Marmeladnitsa, Niva, Orlovskaya zvezda, Orlovchanka, Podarok leta) during the whole period of experimental studies. This fact confirms the technological value of berries of the studied red currant varieties and advantageously characterizes them as a raw material for production of jelly products. The analysis of the obtained data allows revealing a close dependence of texture-mechanical characteristics of the jelly according to the force of load and such indices of chemical composition of the raw material as the pectin substance quantity and the degree of their etherification. It is supposed that the protopectin is able to turn into the soluble pectin during cooking, thus increasing the jelly- forming value of the finished product. The genotypes with higher values of pectin substances and degree of their etherification are characterized by better ability to form jelly.