Comparison On Aroma Compounds Of Soy Sauce And Strong Aroma Type Liquors

Baijiu is a traditional alcoholic beverage with unique aromatic style. Aroma compoundsin Baijiu are responsible for the different flavors. Since many factors could affect aromacharacter and quality of liquor, such as raw materials, starter, manufacturing practices anddevices, Chinese liquors have different flavor characteristics. However, the aroma compounddifferences in different aroma type liquors are unclear. In this study, we chose soy saucearoma and strong aroma type liquors produced in a same factory, Xijiu Distillery in Guizhouprovince. The aims of the present study were (i) to identity important odorants in two typeXijiu liquors by gas chromatography–olfactometry (*&2);(ii) to quantitate and analyze allthe aroma compounds to find out the aroma differences and reasons in these aroma typeliquors.The main results are as follows:(1) The soy sauce aroma and strong aroma type Xijiu liquors with typical aromaticcharacters were studied by GC–O and gas chromatography–mass spectrum (GC–MS). A totalof67aroma compounds were detected in soy sauce aroma type Xijiu liquor,66compoundswere identified; A total of61aroma compounds were detected in strong aroma type Xijiuliquor,57compounds were identified. Significantly aroma differences were detected in theChinese liquors with different aroma styles, for example, aroma intensity of ethyl octanoatewas3.5in strong aroma type liquor, while it was2.3in soy sauce arom type liquor. Aromaintensities of1-propanol, acetic acid,2,3,5-trimethylpyrazine, and2,3,5,6-tetramethylpyrazinewere above3.5in soy sauce arom type liquor, and below3.0in strong aroma type liquor.(2) Aroma compounds in the two type Xijiu liquors were quantitated and analyzed byheadspace–solid phase microextraction (HS–SPME) IROORZHG E\*&06complement withliquid–liquid microextraction (LLME) coupled with*&06DQG*&IODPH LRQizationdetector (FID), including28esters,12alcohols,12acids,10carbonyl compounds,12aromatic compounds,6phenol,4terpenes,4pyrazines,7furans,2sulfides,1acetal, and1lactone. Esters, alcohols, and acids were the most important volatiles in Xijiu, making up atleast90percent of total volatile aroma compounds in concentration.(3) Based on the quantitative results, the odor activity value (OAV) analysis showed that:in addition to esters, alcohols, and fatty acids, some carbonyl compounds, terpenes, andsulfides were also calculated with high OAVs. The most important aroma compounds (OAV≥100) in both type liquors were: ethyl2-methylpropanoate, ethyl butanoate, ethyl2-methylbutanoate, ethyl3-methylbutanoate,3-methylbutyl acetate, ethyl pentanoate, ethylhexanoate, acetaldehyde,3-methylbutanal, and dimethyl trisulfide. OAVs of β-damascone anddimethyl disulfide were above100in soy sauce aroma type liquor.(4) The Xijiu liquors with different typical aromas were chosen for odor profiles analysis.The results revealed that aroma outlines of the two liquor samples were obviously different.The strong aroma type liquor was mainly characterized by sharp fruity, sweet, alcoholic, andfloral aromas. Although soy sauce aroma type liquor was also detected with the correspondingaromas, the strengths of these flavors were much smaller. It had obvious differences in sauce-like, baked and caramel-like aromas, the intensities in soy sauce type liquor were3times of them in strong aroma type liquor.(5) Based on the GC–O and odor profiles analysis, aroma compounds in the two liquorswere determined. In general, the concentrations of fatty acid with less carbon atoms (numberof carbon atoms <4) or branched-chain and the corresponding esters in soy sauce aroma typeliquor were1.5–7times of them in strong aroma type liquor, while those with more carbonatoms in strong aroma type liquor were2–12times of them in soy sauce aroma type liquor.As the important aroma compounds (OAV≥10) with significant differences, theconcentrations of ethyl propanoate, ethyl2-methylpropanoate, benzeneacetaldehyde, and1-propanol in soy aroma type liquor were4–50times of them in strong aroma type liquor,while the concentrations of hexyl acetate, hexyl hexanoate, hexanoic acid, and ethylhexanoate in strong aroma type liquor were5–12times of them in soy sauce aroma typeliquor. The OAVs had the same law, which may be caused by the two different manufacturingpractices and fermenters. Multivariate statistical analysis results showed that the aromacompounds in different aroma type liquors were considered with significantly differentconcentrations, which led to the different flavor characters.