Characterization of the key aroma compounds of wild bitter melon lujiu based on LLE coupled with GC–O–MS and the aroma influence of polysaccharide addition using VASE–GC–MS

Abstract

Wild bitter melon (Momordica charantia L. Var. Abbreviata Ser; WBM) is widely cultivated in East and Southeast Asia. It is made into lujiu with high-quality strong-flavor baijiu and presents a beautiful golden color and harmonious aroma. Lujiu is a type of alcoholic beverage similar to gin. In this study, the aroma profile of wild bitter melon lujiu (WBML) was determined through sensory evaluation, and important aroma-active compounds were identified through liquid–liquid extraction (LLE) coupled with gas chromatography–olfactometry–mass spectrometry (GC–O–MS) and aroma extraction dilution analysis (AEDA). A total of 42 aroma-active compounds were identified, and 28 of them with FD factor ≥ 3 were quantified. Sixteen compounds were pivotal aroma contributors, among which ethyl hexanoate, ethyl pentanoate, ethyl butanoate, ethyl octanoate, and acetic acid had the highest OAVs. Moreover, WBM-sourced aroma compounds were found in WBML, including dihydroactinidiolide, (E,E)-2,4-nonadienal, β-ionone, etc. The extraction parameters of vacuum-assisted sorbent extraction (VASE) were optimized for the first time to analyze lujiu aroma. The effect of homologous polysaccharide addition to the aroma of WBML was explored with VASE–GC–MS. The greasy off-odor was decreased due to the reduction of ethyl octanoate volatility by polysaccharide addition.