Chemical and enzymatic synthesis of a library of 2-phenethyl esters and their sensory attributes.

We report a simple enzymatic approach to synthesise phenethyl esters as natural flavouring materials. Chemical and lipase-catalysed esterification reactions between fatty acids of C4-C18 and 2-phenethyl alcohol were studied. Both methods were compared qualitatively and quantitatively by GC-MS/FID. The acid and thermal stabilities of 2-phenethyl esters were excellent and can meet the requirements of food matrices under most processing conditions. Sensory evaluation showed that each 2-phenethyl ester with a different carbon-chain-length fatty acid had unique sensory notes. Moreover, through Lipozyme TL IM-mediated transesterification, valuable 2-phenethyl alcohol-derived esters were synthesised from butter oil and 2-phenethyl alcohol. The influence of several physicochemical parameters (temperature, substrate molar ratio, enzyme loading, shaking speed and time) on the transesterification reaction was investigated to give optimal reaction conditions, leading to a high yield of 80.0%.