Research of surface-active properties and sizes of pectin molecules after post-alcohol grain distillery dreg

Abstract

From the multicomponent composition of biologically active substances contained in wheat post-alcohol grain distillery dreg, the leading role in the manifestation of surface-active properties is presumably played by pectins. Therefore, the purpose of the work was to isolate pectins from the distillery dreg, study their surface-active properties and determine the size of molecules in the saturated adsorption layer to justify the possibility of using pectins in pharmaceutical practice as auxiliary substances. The physical and chemical characteristics of pectins isolated by the technology of complex processing of distillery dreg were studied: pH of 0.5% aqueous solution (4.25), average molar mass (1650•10-3 kg/mol), degree of polymerization (10), binding capacity to lead (II) ions (282.29 mg/g of pectin). According to a series of pectin solutions with a concentration of 0.5-6.1 mol/m3 the following parameters were determined and calculated experimentally at a temperature of 293 K: surface tension (51.96•10-3-67,55•10-3 N/m), surface activity (7.54), marginal surface excess (6.25•10-5 mol/m2), critical micelle formation concentration (1.48 mol/m3 or 0.24%). The found characteristics of the surface properties of the calculated size of the pectin molecule in a saturated adsorption layer: cross-sectional area (2,658 Å2), weight of pectin per unit area (1,031•10-4 kg/m2), the length of the molecule (1026 Å), the volume of the molecule (Å3 2727), the radius of the cross section of the molecule (0,920 Å), the cross-sectional diameter of the molecule (1,840 Å). The calculated size of the pectin molecule from distillery dreg in a saturated adsorption layer, comparable to the parameters of analogues (beet pectin, polygalacturonic acid, sodium alginate), indicate the biological availability of the tested pectins and creates the prospect of their pharmaceutical use in drug technology.