A combination of glutaminase and pH control prevents the nonenzymatic conversion of L-glutamine into L-2-pyrrolidine-5-carboxylic acid in food processing.

摘要

A strategy using Alicyclobacillus F-62 glutaminase was established to minimize the nonenzymatic production of L-2-pyrrolidine-5-carboxylic acid (L-pyroglutamic acid, savourless amino acid) and maximize the enzymatic production of L-glutamic acid (savoury (umami) amino acid) from L-glutamine in food protein processing. The nonenzymatic production rate of L-pyroglutamic acid was influenced by pH and temperature, and it decreased over a pH range of 4-6 at 30 degrees C. Under optimum conditions (30 degrees C and pH 5.0), the L-glutamic and L-pyroglutamic acids obtained from 1 mM L-glutamine in the presence of glutaminase from Alicyclobacillus F-62 were 0.96 and 0.03 mM, respectively. This novel method is useful for the efficient production of L-glutamic acid during food protein processing..