Studies on the influence of germination conditions on protein breakdown in buckwheat and oats

Abstract

The influence of germination time and germination temperature on protein breakdown in buckwheat and oats was investigated using RSM as a statistical tool. Variations in germination temperature between 10°C and 20°C and germination times between 48 h and 144 h had no statistically significant (p < 0.05) impact on Total Nitrogen (TN) and Soluble Nitrogen (SN) in buckwheat malts; only Free Amino Nitrogen (FAN) increased as a consequence of prolonged germination time. Protease activity was low and was not influenced by the germination parameters. In oat malts, TN was not affected, however the SN increased with prolonged germination times and FAN was also affected by germination time and temperature. Protease activity in oat malts could be strongly increased by choosing appropriate germination conditions. The molecular weight of the malt proteins was investigated using a Lab-on-a-chip system based on capillary electro-phoresis. Protein breakdown was more pronounced in samples germinated for longer times in both grains; however, not all proteins were affected. Proteins in oats appeared to be affected more strongly than the proteins in buckwheat, as a consequence of the higher proteolytic activity in oat malt. © 2010 The Institute of Brewing & Distilling.