Deciphering the Molecular Bittercode in Potato Protein Hydrolysates through a Sensoproteomics Approach

Potato protein hydrolysates (<i>Solanum tuberosum</i> L.) exhibited a strong bitter off-taste. This study aimed to elucidate the origin of this bitter taste; therefore, literature-known bitter tastants such as amino acids, fatty acids, and fatty acid oxidation products were quantified. Using reconstitution experiments, the bitter taste of hydrolysates with low bitterness was explained by the amino acids l-leucine, l-histidine, l-lysine, l-arginine, l-tyrosine, l-isoleucine, l-phenylalanine, and l-tryptophan, as well as palmitic acid; however, the taste of the hydrolysates with high bitterness could not be fully elucidated utilizing literature-known tastants. Using a sensoproteomics approach, including activity-guided fractionation coupled with untargeted/targeted proteomics, 21 new bitter peptides were identified. These peptides showed bitter recognition thresholds ranging from 48 μmol/L (PAF) to 707 μmol/L (DDKDFLPF), suggesting that they are key contributors to the bitterness of the hydrolysate. Using these peptides, new UHPLC-MS/MS methods can be developed to guide the production of less bitter hydrolysates.