The Effect of SO2 on the Production of Ethanol, Acetaldehyde, Organic Acids, and Flavor Volatiles during Industrial Cider Fermentation
文摘
SO2 is widely used in cider fermentation but also in other alcoholic beverages such as wine. Althoughthe authorized limit is 200 ppm total SO2, the International Organizations recommend its totalelimination or at least reduction due to health concerns. Addition of SO2 to apple juice at levelsfrequently used in industrial cidermaking (100 mg/L) induced significantly higher acetaldehydeproduction by yeast than that obtained without SO2. Although the practical implications of acetaldehydeevolution under cidermaking conditions has been overcome by research and few data are available,this compound reached levels in two 2000 L bioreactors that may have prevented the occurrence ofsimultaneous alcoholic and malolactic fermentation. It was observed that malolactic fermentation hada positive effect promoting reduction of acetaldehyde levels in cider fermented with juice, SO2-treatedor not. The addition of SO2 clearly delayed malolactic fermentation comparing to the control, affectingnot the onset of the malolactic fermentation but the rate of malic acid degradation. This compound,however, had a stimulatory effect on alcoholic fermentation.Keywords: Cider; SO2; industrial fermentation; malolactic