EVALUATION BY A MULTIVARIATE-ANALYSIS OF THE STALE FLAVOR FORMED WHILE STORING BEER

When beer was stored for 0, 1, 2, 3, and 4 weeks at 37 degrees C, a stale flavor was generated with the increasing storage period. The 132 peaks detected by a GC analysis of the medium- and high-boiling-point volatiles in beer were used as variables for a multivariate analysis. Fifteen compounds, including furfural and 2-furfurylethyl ether, which had rotated factor loadings of more than 0.5 on a second factor axis, were extracted as components that were highly correlated with the formation of the stale flavor. Furfuryl acetate, 5-methylfurfural, and an unknown compound were extracted by a stepwise discriminant analysis as important indices for the discrimination of beer according to storage period.