Study of biopolymers interactions: protein - polysaccharide isolated from flax seeds

The aim of the study is to investigate the interaction of proteins and polysaccharides obtained from flax seeds. Objectives: to study the phase behavior during the interaction of protein concentrate solutions and flax seed polysaccharides; to investigate the interaction of flax seed proteins and polysaccharides at different pH. The objects of the study were flax seed processing products: protein concentrate, polysaccha-ride extract and their mixtures. Polysaccharides were isolated from flax seeds by extraction, followed by concentration of the extract using a rotary evaporator and drying in a spray dryer. The protein product was obtained by alkaline extraction from mucus-free and defatted flax seeds. To obtain a homogeneous 1 % protein solution, the product was homogenized, followed by holding the solution at 50 °C and constant stirring for 2 hours. To study protein-polysaccharide interactions, protein and polysaccharide solutions were mixed in the ratios of 9:1, 7:3, 1:1, 3:7, 1:9, respectively. Physicochemical parameters were determined using standard analysis methods. The protein content in the products was determined according to GOST 10846-91, and the humidity was determined according to GOST 10856-96. The pH value was measured using an I-160MI laboratory ion meter. Spectrophotometric analysis methods were performed on a PE-5400 spectrophotometer. As in the bovine serum albumin solution, residues of tryptophan, tyrosine, and phenylalanine were found in the spectrum of flax protein in the UV range. When measuring the optical density of solutions of protein, polysaccharides and their mixtures, the behavior of the system was determined by the content of the predominant component. In acidic environments, mixed systems form two-phase systems regardless of the ratio of components. At equal concentrations of the initial solutions (0.3 %), the mixed systems remained monodisperse and stable at neutral pH and a component ratio of 1:1.