A simultaneous assay method for L-glutamate and L-pyroglutamate contents in soy sauce using a 5-oxoprolinase (without ATP hydrolyzing activity).
L-Glutamine and L-glutamate, which are important flavor components in soy sauce, are converted to L-pyroglutamate during brewing. Therefore, it is necessary that the L-glutamate and L-pyroglutamate contents can be measured accurately. We developed a simultaneous assay method for L-glutamate and L-pyroglutamate by using 5-oxoprolinase (without ATP hydrolyzing activity) and glutamate oxidase. By this method, the L-pyroglutamate could be measured accurately in a range of 0.05 to 1.0 mM in the presence of 1.0 mM L-glutamate. This system is effective for process and quality controls.
Nishimura
A
A
Research Laboratory, Ichibiki Co., Ltd., Toyohashi, Aichi, Japan. rl-ichi4@wht.mmtr.or.jp
Itoh
H
H
Oyama
H
H
Murao
S
S
Oda
K
K
D000255:Adenosine Triphosphate; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005421:Flavoring Agents / Q000737:chemistry* / Q000592:standards; D005504:Food Analysis / Q000379:methods / Q000592:standards; D005524:Food Technology; D018698:Glutamic Acid / Q000032:analysis*; D006868:Hydrolysis; D011752:Pyroglutamate Hydrolase; D011761:Pyrrolidonecarboxylic Acid / Q000032:analysis*; D011786:Quality Control; D013025:Glycine max
D005421:Flavoring Agents; D018698:Glutamic Acid; D000255:Adenosine Triphosphate; D011752:Pyroglutamate Hydrolase; D011761:Pyrrolidonecarboxylic Acid