The influence of microelements selenium and copper on the rye malt amylase activity and flour technological properties
¹Latvia University of Agriculture, Faculty of Food Technology, Department of Chemistry, St. Liela 2, LV-3001 Jelgava, Latvia
²Latvia University of Agriculture, Faculty of Food Technology, Department of Food Technology, St. Riga 22, LV-3002 Jelgava, Latvia
*antokrist@inbox.lv
Abstract:
The positive effect of microelement selenium (Se) on the amylase activity and technological properties of malt is well known. Copper (Cu) is an essential microelement required for the normal functioning of living organisms, plants and most microorganisms. The aim of the current research was to investigate the interaction of two microelements – copper and selenium and its influence on the rye malt and flour properties. Rye grain of 96% viability were soaked and germinated at temperature +6 ± 2 °C for 3 days, using Se (VI) containing solution (Se concentration 8.5 mg L-1) or selenium with copper(II) containing solutions (Se concentration 8.5 mg L-1, Cu concentrations 3 mg L-1, 5 mg L-1, 10 mg L-1). After that sample were dried in the oven for 24 hours at temperature of + 73–108 °C. Control sample-germinating rye grain without microelements additives. Activity of amylase was determined in all experimental samples, because it characterizes the malt quality. Amylases are starch hydrolysing enzymes; more over there are known several amylases: α-amylases, β-amylases, isoamylases, etc. with different mechanisms of reaction. There different analytical methods were used for determination of α-amylase activity. The first was Ceralpha method (Megazyme test kits). The second method use complete reagents for quantitative determination of α-amylases (Phadebas Amylase Test). The third was iodometrical method. Different amounts of malt fortified with Se and Cu were added for investigation of rye flour technological properties. The falling number and the maximum viscosity were determined. The obtained results show that analysed additives of microelement copper decreases the enzyme activity. Analysed rye flour technological properties were better using malt only with selenium supplement.