Sleep‐enhancing activity of fermented pea protein hydrolysate with enhanced GABA content by Lactobacillus brevisSYLB 0016 fermentation

Abstract BACKGROUND Sleep is essential for overall health and wellbeing. This study investigated the sleep‐promoting effects of fermented pea protein hydrolysate (PPF) with increased gamma‐aminobutyric acid (GABA) content produced by Lactobacillus brevis SYLB 0016. The effects of PPF on sleep duration and structure were assessed in pentobarbital‐induced ICR mice and Sprague Dawley (SD) rats using electroencephalogram (EEG) analysis. RESULTS Hydrolysis of pea protein with Alcalase, Protana Prime, and Protana UBoost increased the amino nitrogen content, degree of hydrolysis and glutamate content to 160.51 mmol L −1 . Fermentation by Lactobacillus brevis SYLB 0016 increased the GABA content from 3.16 to 90.35 mmol L −1 . PPF significantly increased sleep duration (56.3 min) compared to the normal control (30.6 min) in pentobarbital‐induced sleep tests. Non‐rapid eye movement (NREM) sleep time increased with a significant rise in δ‐waves activity following administration of 150 mg kg −1 of PPF. In caffeine‐induced insomnia, both low‐ and high‐dose PPF significantly increased sleep duration. Three weeks of oral PPF administration elevated GABA A and GABA B receptor expression, with GABA A receptor protein levels showing a significant change. Co‐administration of flumazenil with PPF reduced sleep time, indicating the involvement of the GABA A receptor benzodiazepine site in PPF's sleep‐enhancing effects. CONCLUSION In conclusion, PPF with enhanced GABA content improves NREM sleep by increasing δ waves activity. As a hypoallergenic compound, PPF holds potential as a supplement to ameliorate sleep disorders. © 2025 Society of Chemical Industry.