Change in the content of phenolic compounds in semi-finished products from endive Cichorium endivia during low-temperature processing

Abstract

BACKGROUND: Research on changes in the content of monomeric and dimeric phenolic compounds and their amount during freezing and storage of semi-finished products is relevant because the varieties of endive Cichorium endivia, which have many useful elements, are applicable for medical and dietary nutrition. AIM: This article aimed to analyze the kinetics of the oxidation and hydrolysis reactions of phenolic compounds of three varieties of endive during freezing and storage. MATERIALS AND METHODS: The total content of phenolic compounds and the amount of phenolcarboxylic acids and flavonoids in fresh vegetables and semi-finished products from Russian varieties Kruzhevo and Elvira endive, as well as the Italian variety Kornetto K-56, were determined by spectrophotometry in fresh endive after harvesting, then after homogenization, freezing, and periodically in the process of low-temperature storage. RESULTS: Kinetic dependencies of changes in the content of phenolic compounds on the duration of storage of semi-finished products from endive varieties Kruzhevo, Elvira, and Kornetto K-56 in a frozen state were revealed. The constants of the reaction rate (pseudo-first order) of the change in the content of the studied substances during storage of endive semi-finished products were calculated. To reduce the loss of cell sap during defrosting to maintain the amount of phenolic compounds during storage of endive semi-finished products, adding pectin in the homogenization stage at an amount of 3.0% by weight of the homogenized endive of the varieties under study is recommended. CONCLUSIONS: During storage of endive, phenolic compounds are preserved to the maximum, and cell sap losses are reduced within 180 days in the Elvira and Kruzhevo varieties, and within 150 days in the Kornetto K-56 variety. The frozen semi-finished product from homogenized endive of the studied varieties is recommended for use in healthy nutrition technologies, particularly in the production of low-calorie drinks and bakery and confectionery products.