采用ASTM679标准方法测定了未除气与除气淡爽型啤酒中乙酸、乳酸、柠檬酸、苹果酸、琥珀酸、富马酸、丙酮酸、酒石酸和草酸的个人和小组阈值。结果发现,在未除气啤酒中,9种有机酸的小组阈值大小顺序为苹果酸、富马酸、乳酸、柠檬酸、丙酮酸、琥珀酸、乙酸、草酸、酒石酸。其中品评员对苹果酸、琥珀酸、富马酸、草酸和柠檬酸的口感差异相对较小,而对酒石酸、乙酸、丙酮酸和乳酸的口感差异较大。在除气啤酒中,9种有机酸的小组阈值大小顺序为丙酮酸、乳酸、乙酸、富马酸、琥珀酸、苹果酸、酒石酸、草酸、柠檬酸。品评员对柠檬酸、苹果酸和乳酸的口感差异相对较小,而对丙酮酸、草酸、酒石酸、富马酸、琥珀酸和乙酸的口感差异较大。此外还发现未除气和除气啤酒中有机酸阈值差异很大,其中差异最大的是三元酸柠檬酸,其次为二元酸,包括苹果酸、草酸、酒石酸、琥珀酸和富马酸,差异最小的是一元酸,包括乳酸、乙酸和丙酮酸。

The individual and group thresholds of nine organic acids were measured in control and degassed beer using the ASTM method 679 protocol.The results show that the group threshold of malic acid in control beer had the highest value in the 9 organic acids,followed by fumaric acid,lactic acid,citric acid,pyruvic acid,succinic acid,acetic acid,oxalic acid and tartaric acid in rank.The panelists have relative small differences in taste of malic acid,succinic acid,fumaric acid,oxalic acid and citric acid in the control beer,and the great discrepancy in mouth-feel of tartaric acid,acetic acid,pyruvic acid and lactic acid.The group thresholds of nine organic acids in degassed beer followed by pyruvic acid,lactic acid,acetic acid,fumaric acid,succinic acid,malic acid,tartaric acid,oxalic acid and citric acid in rank.The panelists have relative small differences in taste of citric acid,malic acid and lactic acid,and the great discrepancy in mouth-feel of pyruvic acid,oxalic acid,tartaric acid,fumaric acid,succinic acid and acetic acid.Besides,we have found significant difference in the group thresholds of nine organic acids between degassed and control beers.Triprotic acid has more significant difference than other acids,and monoprotic acid was the smallest among these acids,while binary acid lie in the middle.