Meat protein hydrolysates and their advanced glycation end-products as sources of bitter taste modifiers

Protein hydrolysates have been shown to be sources of various bioactive peptides but there is scanty information on their ability to act as bitter taste modifiers. Meat has multiple proteins and offers the possibility of generating a wide range of peptides with desirable function as bitter taste modifiers. In this study, beef protein was hydrolyzed with each of six commercial enzymes (Alcalase, Chymotrypsin, Trypsin, Pepsin, Flavourzyme, and Thermoase). Using an electronic tongue showed that Alcalase hydrolysates (AH) had significantly (P<0.05) lower bitter scores compared to other enzymatic hydrolysates. Separation of the AH and chymotrypsin hydrolysate (CH) by RP-HPLC yielded peptide fractions with significant ability to inhibit quinine activation of a human bitter taste receptor (T2R4) in HEK 293 cells based on calcium imaging assays. Eight peptides were identified from the T2R4-inhibitory AH and CH fractions, most of which were dominated by leucine and polar amino acids.