Modification of the Process of Obtaining Pectin by the Methods of Membrane Technology

Abstract

The proposed approach to the processing of plant materials using membrane methods is new in the field of de - veloping new methods for isolating pectin substances and obtaining not only pectin itself, but also new low-cost high-quality pectin-containing products. The studies were carried out on pressings obtained after squeezing juice from citrus fruits (Georgia): lemon (“Meer”), Washington-Navel orange variety, “Unshiu” mandarin and the largest citrus pomelo fruit (China). From the fruits harvested in April-December, the juice was squeezed out and from the remaining mass, which was crushed, by adding HCl (1:10) pectin isolates were obtained, which were concentrated by ultrafiltration. Soluble pectin was precipitated from the concentrated extract with ethyl alcohol, i.e. converted to an insoluble form. The resulting precipitate was thoroughly washed with alcohol and then dried at T = 55°C. The concentration of isolates was carried out by tangential filtration in dynamic mode on a UPL-06 unit, an AR-0.2 ultrafiltration separating apparatus was used as a membrane, which was located vertically in the unit and was a ready-made module with a filtration area of 2 m 2 ; obtained on the basis of polyamide and phenylone – C 2-B hollow fibers VPU-15PA with a pore size of 500 A. Ultrafiltration was carried out in circulation mode to the maximum possible concentration of the extract. The dependence of the productivity of the process of purification-concentration of pectin extracts from citrus fruit waste without their morphological division, pressure, duration and filtration mode, type and term of fruit harvesting was studied. The work performed has shown that the use of semi-permeable membranes for concentrating pectin extracts allows: to a large extent to remove carbohydrates from the extract, to achieve partial discoloration of the pectin extract; ensure 100% retention of pectin substances by membranes; to achieve a high degree of concentration of the extract and made it possible to obtain a pectin preparation with a purity of 95%. The proposed technology using membrane technology makes it possible to ob - tain pectin with a purity of 95% or more by purifying it from ballast impurities at the stage of extract concentration.