Structures, orosensory activity, and T1R1/T1R3 receptor activation of amides generated by lactone aminolysis using food-related processing conditions

Aimed at the discovery of taste-active and taste-enhancing compounds formed upon food processing, a total of 16 amides were generated by aminolysis of odor-active lactones under kitchen-like, soft processing conditions using the food-related solvents ethanol, medium-chained triglycerides, and sunflower oil, respectively. Human sensory studies revealed a bitter or pungent intrinsic taste of these amides, among which N -phenethyl-4-hydroxypentanamide, N -phenethyl-( 4R )-hydroxypentanamide, N -phenethyl-5-hydroxypentanamide, N -(4-hydroxy-3-methoxybenzyl)-4-hydroxypentanamide, N -(4-hydroxy-3-methoxybenzyl)-5-hydroxypentanamide, and N -(3-hydroxy-4-methoxybenzyl)-5-hydroxypentanamide also exhibited umami taste-enhancing activity in a binary mixture of monosodium l -glutamate and guanosine 5′-monophosphate. Cell-based T1R1/T1R3 taste receptor assays tendentially confirmed the umami enhancement activity, but only reached significance for N -(4-hydroxy-3-methoxybenzyl)-5-hydroxypentanamide. LC–MS/MS screening of selected amides in various fermented food products finally led to the unequivocal identification of N -phenethyl-4-hydroxypentanamide, formed by the reaction of γ-valerolactone and phenethylamine, in blue cheeses.