Comparison between barley malt protein quantification methods

Abstract Brazil imports about 60% of all the malt used by the brewing industry which is spread throughout the country. Even though it is an agricultural country, only a small portion of the barley production has the characteristics to produce barley malt for brewing. Seeking supply to the ever-growing demand and reducing the dependency on other countries and logistic costs, malting industries and genetic enhancement companies endeavor to adapt barley to the Brazilian Savannah conditions. For the barley to be malted, it is crucial to develop cultivars with the necessary malting qualities and adapted to the region and with good yield. Considering the importance of protein to the brewing process, four protein quantification methods were compared: combustion methods - carbon, hydrogen and nitrogen elemental analysis and Dumas - and digestion ones - Kjeldahl and flux injection analysis (FIA). The methodologies tested showed good correlations (higher than 0.881) and variations were associated with matrix complexity. All protein quantification methods were satisfactory from an agronomic perspective. Yet, we recommend the combustion ones as they generate fewer residues and results are ready in up to 6 minutes. Therefore, they are the most suited for barley and malt analysis considering lab routine.