Buckwheat malting: grain steeping methods and their influence on the malt quality

The aim of the work was to study the influence of the steeping methods on the change in the activity of amylolytic enzymes during malting of buckwheat grain and the quality of malt. The research problems were to establish the influence of steeping methods on the changes in moisture content, amylolytic activity (AC) and the activity of α- and β-amylases during grain germination; to investigate the quality specification of buckwheat malt. The objects of the research were buckwheat grain Fagopyrum esculentum cultivar Izumrud and Pry 345 (protein content 13.1 and 11.2 %, respectively) and the malt obtained by air-water, air-spray and spray steeping methods. The moisture, the activity of α-, β-amylases of grain during germination and extract, proteolytic modification, AC, viscosity, acidity of malt after store maturation were investigated. The results showed that steeping method as well as buckwheat cultivar did not have any significant effect on the accumulation of moisture in malting which content in green malt was 53 %. The change in the AC level of germinating grain for different steeping methods was the same and made: in Pry 345 300-312 units W-K, in Izumrud - about 400 units W-K. It was revealed a gradual increase in the activity of α-amylase during malting to 80-96 mg/g, but the level of β-amylase sharply increased to 11.5-12.0 mg/g for 24 hours and then did not change. Essential effect of steeping method on these enzymes’ activity was not reveled. The analysis of physical and chemical properties of the buckwheat malt showed that steeping method had made it possible to regulate only certain characteristics of its quality but did not make it possible to obtain high quality malt according to all indicators. It is necessary to look for the methods to improve the malt quality at other stages of malting - germination and malt kilning.