Известия высших учебных заведений. Поволжский регион: Естественные науки (Dec 2022)
Comparison of amylases and antioxidant enzymes (catalases and peroxidases) activity in the grain malting of various barley varieties
Abstract
Background. As a result of malting, a number of enzymes are activated in the grain, among which hydrolytic and antioxidant enzymes are of great importance. The activity of enzymes and the quality of malt depends not only on the conditions of growth, storage and germination conditions, but also largely on the genetically determined varietal characteristics of the grain. In this regard, the purpose of our research was to evaluate the activity of amylases, catalases, and peroxidases in the process of malting spring barley seeds, depending on the genotypic characteristics of varieties of different origin. Materials and methods. In laboratory studies, seeds of 15 varieties of spring barley (Hordeum vulgare) were used, which differed in origin. Barley grains were germinated on water for 7 days at a temperature of 12-14 °С. In sprouted grain, the activity of amylolytic enzymes was determined by the method of iodine-starch test, catalases - according to Bach and Oparin, peroxidases - by the method of tyrosine peroxidation. The catalytic activity of the isoforms of these enzymes at pH=5.5, 7.0, 8.0 was evaluated using a phosphate buffer system (1/15 M phosphate buffer). Results. In the grain of 7-day-old seedlings, the Raushan, Xanadu and Cherio varieties had the highest activity of all amylase isoenzymes (acidic, neutral, alkaline), which increased their endosperm solubility during malting. In the barley varieties Nadezhny and Xanadu, the activity of all catalase isoenzymes was increased in the germinated grain, and in the Vladimir, Xanadu and Pioneer varieties, all isoforms of peroxidases were increased. The high level of activity of these enzymes stabilized the biochemical processes in the germinated grain and thus increased the ability of the grains to malt.
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