In situ production of γ-aminobutyric acid in breakfast cereals

Abstract Breakfast cereals are an important part of an equilibrated diet in the Western world, making them extremely suited for carrying health benefits. Intake of γ-aminobutyric acid (GABA), a major inhibitory neurotransmitter of the nervous system, has been related to blood pressure lowering in hypertensive individuals. In vivo , GABA is formed from glutamic acid (GA) by glutamic acid decarboxylase (GAD), a widely distributed enzyme in prokaryotic and eukaryotic species. We here enriched breakfast cereals with GABA by recipe and process optimisation. The dynamics of GA and GABA were monitored throughout the production process. Addition of exogenous recombinantly produced GAD of Yersinia intermedia increased GABA levels by 2- to 5-fold. As only trace levels of GABA (