Genetic and environmental impact on protein profiles in barley and malt

Canadian barleys have higher protein content and better protein modification than Australian barleys. Protein and protein modification was investigated in two Australian and two Canadian barley varieties under different levels of nitrogen fertilisation. Mass spectrometry was used to analyse protein profiles in grain and malt to assess how genetic and environmental factors modified the proteins in grain and malt. The differences in grain protein between the Australian and Canadian varieties were mainly in the high molecular weight proteins, less in water soluble proteins and rarely in salt-soluble proteins, while malt protein variations were observed in all three groups. Generally, Canadian varieties contained more proteins in grain, but less water soluble and salt soluble proteins in malt. Monitoring the protein modification during the malting indicated that more proteins were digested in Canadian varieties. Genetic factors were dominant for protein variation, although environment also affected the protein composition. Barley varieties growing in Canada generally contained slightly higher protein content, and nitrogen fertiliser influenced proteins in grain that ranged from 43,000 to 47,000 Da. The protein pattern of high fermentability and lower fermentability varieties mainly varied from 30,000 to 40,000 Da. © 2018 The Institute of Brewing & Distilling