Influence of spices on the variation in gamma-aminobutyric and glutamic acids during low-salt bread production

This study investigated the effects of 14 different spice extracts on the levels of γ-aminobutyric acid (GABA) and glutamic acid (Glu) during the production of low-salt bread.GABA and Glu contents were measured at three stages: kneading, fermentation, and baking.In control bread, GABA levels decreased progressively, whereas certain spices-such as basil, peppermint, yuzu peel, and macehelped retain or increase GABA levels at specific stages.Basil promoted GABA synthesis during fermentation, while peppermint, yuzu peel, and mace were effective during baking, likely through the activation of wheat-derived glutamate decarboxylase (GAD).These spices also contributed to the retention of Glu in the baked bread.A positive correlation was observed between changes in Glu and GABA, suggesting that GABA synthesis is modulated by Glu metabolism.These findings indicate that the addition of specific spices may serve as a practical approach to increasing GABA and Glu contents in low-salt bread.