Chemometric-based gamma-aminobutyric acid and amino acids profiling of fermented Okpeye using ultra-high-performance liquid chromatography diode-array detector (UHPLC-DAD)

Abstract Okpeye, a traditional West African fermented seasoning made from Prosopis africana seeds, is recognized for its flavour and nutritional benefits, especially its bioactive gamma-aminobutyric acid (GABA), which exhibits neuroprotective, antihypertensive, and anti-diabetic properties. This study applied an Ultra-High-Performance Liquid Chromatography Diode-Array Detector (UHPLC-DAD) and principal component analysis (PCA) to profile GABA and amino acids in four Okpeye samples (locally-sourced and laboratory-produced). Results showed significant variations in GABA content, ranging from 22.86 to 48.06 mg/100 g dry fermented Okpeye across samples. PCA analysis revealed two main components, explaining 83.39% of the variance, which highlighted leucine, lysine, and GABA as key differentiating metabolites. Additionally, a strong positive correlation was observed between GABA and its precursor, glutamic acid, underscoring the role of fermentation in enhancing nutritional quality. This study suggests optimizing fermentation conditions could improve GABA production, maximizing Okpeye’s health benefits as a functional food.