Modes and methods of treatment of blackcurrant pomace with an enzyme preparation to increase juice yield

Abstract

Blackcurrant is a multivitamin crop with high dietary and medicinal properties and is a source of exceptionally valuable raw materials for juice production, but its extraction is complicated by its chemical composition. The endocarp of blackcurrant fruit (the actual pulp) is formed by the slimy arylus surrounding the seeds, which prevents juice extraction. The purpose of this study was to scientifically substantiate the modes and methods of effective extraction of blackcurrant juice with preliminary enzymatic treatment of the pomace while preserving its natural chemical composition and biologically active substances. The study was conducted with blackcurrant fruits of the varieties Mynai Shmyrev, Belarus sweet, Novyna Prykarpattia in the laboratory of the Department of Technology of Storage and Processing of Plant Production and the Training and Production Department of the Uman National University of Horticulture. Research methods (physical, chemical, physical-chemical) and statistical processing of results (analysis of variance) are generally accepted. Blackcurrant fruit usually yields an unsatisfactory juice yield of 18-24%, which lacks its inherent colour. According to Harrington’s desirability assessment, enzymatic treatment with pectofoetidine increases the juice yield from crushed fruit to satisfactory (37-44%) and very good (57-60%) for crushed fruit (pomace), which is 2-3 times higher. During the fermentation of pomace, three stages are distinguished: the first is the destabilisation of the colloidal system of the pomace (up to 1 hour); the second is the degradation of the pomace structure (up to 2 hours); and the third is the stabilisation of the process (after 3 hours). Optimum conditions for pomace fermentation are ensured by using 0.03% by weight of the preparation suspension, a temperature of 42-45 °C, and a process duration of 2 h. This results in up to 60% juice extraction, 96-102% acid conversion and up to 97% ascorbic acid content. The increase in juice yield by 6-15% correlates with the characteristics of the variety. In juices with sugar, the content of ascorbic acid is 1.7 times lower, but its preservation reaches 98-99%. Sugar and hot bottling are the factors that stabilise ascorbic acid in juices. Increasing juice yield and improving its quality is economically and technologically feasible