Influence of phytase and supportive enzymes applied during high gravity mash preparation on the improvement of technological indicators of the alcoholic fermentation process

Abstract

Phytic acid is one of the compounds that can limit the availability of biogenic substances responsible for the environmental stress response of the yeast. The aim of the study was determining the influence of hydrolysis of the phytic acid complexes in the HG maize mashes on the availability of free amino nitrogen (FAN) released from hydrolyzed proteins and the resulting change in the fermentation activity of the yeast. Prospects for the optimization of the alcoholic fermentation process by combined application of phytase, protease and augmented set of amylolytic enzymes were also assessed. The application of protease phytase resulted in an increase of FAN concentration during subsequent hours of the alcoholic fermentation process which indicated an increased availability of proteins susceptible to hydrolysis. A positive effect of combined application of phytase, protease and amylolytic enzymes (with pullulanase) on technological indicators of the fermentation process was observed. The final ethanol concentration increased by 1% v v−1 and the yield increased by 6 L EtOH 100 kg−1 of starch. The optimization of the mashing process, involving the application of additional enzymes (phytase, pullulanase, protease), improved the yield of fermentation in relation to the theoretical yield to the level of 93%. A combined application of α-amylase, pullulanase, glucoamylase, protease and phytase during HG mashes preparation lowered the concentration of higher alcohols by 450 mg L−1 EtOH, on average, as compared to the control variant. At the same time, the concentration of acetaldehyde in the spirits increased above 480 mg L−1 EtOH.