Kokumi Substance Obtained from Vegetable Protein Hydrolysates through Salt-Free Processing

The kokumi substance of enzymatic hydrolyzed vegetable protein (EHVP) was isolated and evaluated for its effects on sensory perception. Sensory evaluation revealed that the addition of EHVP to beef extract solution significantly enhanced flavors such as mouthfulness and astringency. EHVP was fractionated through ultrafiltration and chromatography, and kokumi-containing fraction was isolated via sensory evaluation. The kokumi substance in EHVP was a glycopeptide consisting of a tetrapeptide and a N-linked glycan with seven sugars. This glycopeptide that exhibited no taste-activity when dissolved in water alone.. However, in the presence of taste-active compounds, such as the beef, the minimum effective concentration of this kokumi glycopeptide required to enhance mouthfeel and astringency was determined to be 1 ng/g, indicating an exceptionally low taste threshold. Sensory evaluation of the prepared analogs revealed that the main structure contributing to koku resided in the peptide part. Conversely, the glycan part enhanced the koku of the peptide.