Taste-guided fractionation and instrumental analysis of hydrophobic compounds in sake.
The taste-active hydrophobic compounds in a charcoal-untreated sake sample were subjected to a taste dilution analysis (TDA). All of the high-TDA factor fractions showed a bitter or astringent taste in common, but their taste characters were different. The taste-active compounds of the high-TDA factor fractions were purified by taste-guided fractionation, using RP-HPLC and an instrumental analysis. From each of the seven fractions, ferulic acid, ethyl ferulate, tryptophol, three previously reported bitter-tasting peptides, and two novel ethyl esters of the peptides of 10 amino acid residues were identified. All the identified compounds had a similar taste character to that of the TDA fractions analyzed. Ethyl ferulate and the ethyl ester of the peptides showed a moderately bitter taste. The concentration of the identified compounds in seven jyunmai-type sake samples was determined. This concentration was decreased dose dependently by a charcoal treatment which is commonly applied in the final step of sake manufacture, notably with the compounds of high hydrophobicity.
Department of Biological Resource Sciences, Akita Prefectural University, Nakano Shimoshinjyo, Akita, Japan. hashizume@akita-pu.ac.jp
Katsumi
K
Hashizume
Toshihiko
T
Ito
Misako
M
Shimohashi
Atsufumi
A
Kokita
Tetsuo
T
Tokiwano
Masaki
M
Okuda
D000434:Alcoholic Beverages / Q000032:analysis*; D002109:Caffeic Acids / Q000032:analysis; D002606:Charcoal / Q000737:chemistry; D005591:Chemical Fractionation; D002851:Chromatography, High Pressure Liquid; D056148:Chromatography, Reverse-Phase; D003373:Coumaric Acids / Q000032:analysis; D004952:Esters; D057927:Hydrophobic and Hydrophilic Interactions; D007211:Indoles / Q000032:analysis; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D010455:Peptides / Q000032:analysis; D013649:Taste; D000438:Alcohols
D002109:Caffeic Acids; D002606:Charcoal; D003373:Coumaric Acids; D004952:Esters; D007211:Indoles; D010455:Peptides; C005949:tryptophol; D000438:Alcohols; C099085:ethyl ferulate; C004999:ferulic acid