Taste enhancements between various amino acids and IMP.
It is well known that a strong synergistic interaction of umami occurs between L-alpha-amino acids with an acidic side chain, such as L-Glu or L-Asp, and 5'-mononucleotides, such as inosine 5'-monophosphate (IMP). We tested taste interactions between various L-alpha-amino acids and IMP by the psychophysical method and found that taste enhancement occurred when IMP was added to several sweet amino acids, such as L-Ala, L-Ser and Gly. The enhanced quality of taste was recognized as umami, and was not blocked by the sweetness inhibitor +/-2-(p-methoxyphenoxy)propanoic acid. The total taste intensities of various concentrations of the amino acid and IMP mixtures were measured using magnitude estimation. The results showed that the potentiation ratios were larger than 1 in the cases of L-Ala, L-Ser and Gly. However, the ratio was approximately 1 in the case of D-Ala, which had an enhanced taste of sweetness. Thus the umami taste enhancement of several sweet L-alpha-amino acids by IMP was synergistic rather than additive as that of acidic amino acids.
Kawai
Misako
M
Food Research and Development Laboratories, Ajinomoto Co., Inc., 1-1 Suzuki-cho, Kawasaki-ku, Kawasaki 210-8681, Japan. misako_kawai@ajinomoto.com
Okiyama
Atsushi
A
Ueda
Yoichi
Y
D000328:Adult; D000409:Alanine / Q000737:chemistry; D000596:Amino Acids / Q000737:chemistry / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D005998:Glycine / Q000737:chemistry; D006801:Humans; D007291:Inosine Monophosphate / Q000737:chemistry* / Q000494:pharmacology; D008297:Male; D010647:Phenyl Ethers; D011422:Propionates / Q000737:chemistry; D012694:Serine / Q000737:chemistry; D013649:Taste; D013650:Taste Buds; D013652:Taste Threshold; D013997:Time Factors
D000596:Amino Acids; D010647:Phenyl Ethers; D011422:Propionates; D007291:Inosine Monophosphate; C091421:2-(4-methoxyphenoxy)propanoic acid; D012694:Serine; D000409:Alanine; D005998:Glycine