Fingerprint of aroma-active compounds and odor activity values in a traditional Moroccan fermented butter “Smen” using GC–MS–Olfactometry

Abstract

Smen is a fermented Moroccan butter highly regarded for its unique flavor characteristics. For the first time, this study aimed to evaluate the suitability and complementary performance of purge-and-trap extraction (PTE) and solvent-assisted flavor evaporation (SAFE) extraction methods prior to gas chromatography–mass spectrometry–olfactometry (GC–MS–O) in order to characterize key compounds in Smen. According to the representativeness tests, both SAFE and PTE aromatic extracts gave satisfactory similarity and intensity scores and were representative aromatic extracts, being similar to the Smen reference odor. Thirty-four volatile compounds were identified in Smen including acids, alcohols, esters, and ketones. Aroma extract dilution analysis (AEDA) was applied to characterize potent odorants, and odor activity values (OAVs) were calculated to authenticate these compounds. Twenty-two and nineteen aroma-active compounds were revealed by SAFE and PTE methods, respectively, with flavor dilution (FD) factors ranging from 4 to 4096, and OAVs between 1 and 3359. Ethyl butanoate, ethyl lactate, ethyl hexanoate, butanoic acid, and hexanoic acid were the main potent odorants in Smen, producing fruity-rose, creamy-whey, overripe fruit, ripened cheese, and rancid buttery/soapy odors, respectively. Therefore, SAFE and PTE methods were not only representative, but also complementary for elucidating potent aroma compounds of Smen.