Production of GABA in milk fermented by Bifidobacterium adolescentis strains selected on the bases of their technological and gastrointestinal performance

There is an increasing interest in producing foods enriched in gamma-aminobutyric acid (GABA), due to their purported health promoting attributes. GABA is the main inhibitor neurotransmitter of the central nervous system, and several microbial species are capable to produce it through decarboxylation of glutamate. Among them, several lactic acid bacteria species have been previously investigated as an appealing alternative to produce GABA enriched foods via microbial fermentation. In this work we report for the first time an investigation into the possibility of utilizing high GABA-producing Bifidobacterium adolescentis strains as a mean to produce fermented probiotic milks naturally enriched in GABA. To this end, in silico and in vitro analyses were conducted in a collection of GABA-producing B. adolescentis strains, with the main goal to scrutinize their metabolic and safety traits, including antibiotic resistance patterns, as well as their technological robustness and performance to survive a simulated gastrointestinal passage. One of the strains, IPLA60004, exhibited better survival to lyophilization and cold storage (for up to 4 weeks at 4 °C), as well as survival to gastrointestinal passage, as compared to the other strains under investigation. Besides, the elaboration of milk drinks fermented with this strain, yielded products with the highest GABA concentration and viable bifidobacterial cell counts, achieving conversion rates of the precursor, monosodium glutamate (GMS), up to 70 %. To our knowledge, this is the first report on the elaboration of GABA enriched milks through fermentation with B. adolescentis.This work was supported by the projects RTI2018-095021-J-I00 and RTI2018-096339-B-I00 funded by MCIN/ AEI /10.13039/ 501100011033/ and by ERDF A way of making Europe; and by AYUD2021-50910 from the autonomic Government of Principado de Asturias (FICYT, supported by FEDER). H. Tam´es acknowledges his predoctoral “Severo Ochoa” fellowship (BP17-55) to the Regional Government of the Principado de Asturias. C Sabater is a postdoctoral researcher supported by the Juan de la Cierva-Formacion ´ Postdoctoral Trainee Program from MICINN, the Spanish Ministry of Science and Innovation (FJC2019- 042125-I)