Abstract:[Objective] This study aims to address the technical problems of insufficient nitrogen content and an imbalanced amino acid composition in very high gravity wort produced with high-level syrup adjuncts.[Method] This study investigated the effect of protease-assisted saccharification on wort protein composition. Then, a comprehensive evaluation was conducted on the brewing performance during 22 °P very high gravity beer production.[Result] During the proteolysis stage of saccharification, a synergistic addition of neutral protease and flavourzyme protease at a mass ratio of 6∶4 enabled efficient directed hydrolysis of malt proteins. In the wort, the α-amino nitrogen mass concentration was increased by 30%, while the mass concentrations of A- and B-type amino acids were increased by more than 30%. In addition, the mass concentrations of soluble nitrogen and foam proteins were increased by over 10%, with a more proper distribution of nitrogenous substances among the A, B, and C fractions. The degradation rate of reducing sugar, the reducing capacity of diacetyl and acetaldehyde, and other fermentation performance were also enhanced significantly.[Conclusion] The 22 °P very high gravity wort produced using this compound protease hydrolysis strategy supported continuous yeast reuse for five generations without a significant decline in yeast viability, meeting industrial fermentation requirements. Furthermore, beer foam quality was improved while the mellow taste and overall sensory harmony were enhanced.
