Reducing higher alcohols by nitrogen compensation during fermentation of Chinese rice wine

Excessive amount of higher alcohols in alcoholic beverages causes unwell and side-effect for consumers although adequate consumption offers joy and pleasure. Therefore, reducing higher alcohols in alcoholic beverages is necessary. We used nitrogen compensation to reduce higher alcohols with Chinese rice wine as an experimental model. Higher alcohols including isobutyl alcohols, isoamyl alcohols, and β-phenethyl alcohols were significantly decreased by 19.27, 23.03 and 19.43%, respectively, when 200 mg/L (NH4)2HPO4, 5% (w/v) yeast, and 11% wheat Koji were added to fermentation broth. Meanwhile, important quality parameters remained unchanged including free amino acids, organic acids, biogenic amines, and esters. The expression of glutamate dehydrogenase 1 gene (GDH1) and glutamine synthetase gene (GLN1) was significantly enhanced, 26.9- and 1.9-folds respectively. These results suggest that ammonium compensation could effectively decrease higher alcohols in Chinese rice wine by activating glutamate dehydrogenase (GDH) pathway in ammonium assimilation.