Influence of the maturity of the fruit material on various components and taste of ume liquor

摘要

To examine the influence of the maturity of ume fruit (Japanese apricot, Prunus mume SIEB. et ZUCC.) on the taste of ume liquor, we analyzed various taste components, pectic substances and cyanogenic glycosides in the liquor aged for three months and the corresponding fruit material picked on six different occasions between May 14 and July 1. We also evaluated the bitterness, aroma and taste of the liquor according to a 5-level numerical scale. The following results were obtained: (1) The liquor made from ume fruit picked after June 11 exhibited a slight increase in red and yellow color along with a delay in the harvesting date, and the lightness gradually decreased. (2) Organic acid composition in the liquor changed with almost the same tendency as that of the fruit material. (3) Ume liquor made after June 11 easily exhibited inversion of sucrose to glucose and fructose, and the sugar penetrating into the flesh of the fruit during aging inverted to structural sugars easier than that in the liquor. (4) Total pectin level in ume fruit removed from the liquor and the corresponding fruit material was not greatly different. (5) Amygdalin was barely detectable in the liquor. The ume liquor made on May 14 contained 69.0 mg prunasin in 1000 ml liquor, but this gradually decreased with the picking time of the fruit material occurring late. (6) The evaluation score of the sensory test for bitterness gradually decreased in accompaniment with a delay in the picking time of the fruit material, and that for aroma and taste increased little by little. The scores of sensory test for bitterness and prunasin levels showed a correlation at r=0.83 (p<0.05). From these results, we would like to propose that the fruit reaped at ripe or over-ripe stages is the optimum material for ume liquor because the liquor produced from such fruit barely exhibits bitterness and is favorable in aroma and taste.