Fourier-transform infrared spectroscopy in a comparative study of animal and plant proteins

The method of infrared attenuated total reflection spectroscopy was used to compare proteins (sarcoplasmic, myofibrillar, stroma) contained in the pork muscle tissue, globular proteins obtained from industrially crushed flax seeds, as well as protein-polysaccharide complexes extracted from husked seed coats and whole seeds. Protein components were isolated from saline solutions by precipitation with a threefold excess of 96% ethanol and 5% trichloroacetic acid, as well as by isoelectric precipitation at pH = 4.2. It is shown that the use of different anatomical parts (core and seed coat), including crushed or whole forms and flax seed meal, under varying conditions of pre-treatment, extraction and isolation allow biologically active protein-containing products to be obtained. Such products - protein concentrates, peptide polysaccharides and protein-lipid-polysaccharide complexes with a variable composition and ratio of components - are valuable raw materials for the food industry, medicine, pharmacopoeia and cosmetology. A comparative study of the kinetics of air drying of crude plant and animal globular proteins at 20°C showed these proteins to be similar in terms of extreme changes in the spectra of light absorption curves and the intensity of the main characteristic bands upon moisture removal. Temperature changes, affecting the general appearance of light absorption spectra, lead to deformation of the Amide-I band, which carries information about the protein structure. Deformational changes may be promoted not only by differentiation of globular proteins (albumins and globulins), but also by packing of their polypeptide chains during reconstruction or formation of a new secondary structure destroyed as a result of various mechanical and chemical interventions. According to the obtained data, elevated temperatures have a significant effect on the structural transformations of both protein concentrates and protein-polysaccharide complexes, regardless of their nature.

plant and animal proteins, protein-containing products, infrared reflection spectroscopy