Investigating the Variation of Volatile Compound Composition in Maotai-Flavoured Liquor During Its Multiple Fermentation Steps Using Statistical Methods.

The use of multiple fermentations is one of the most specific characteristics of Maotai--flavoured liquor production. In this research, the variation of volatile composition of Maotai-flavoured liquor during its multiple fermentations is investigated using statistical approaches. Cluster analysis shows that the obtained samples are grouped mainly according to the fermentation steps rather than the distillery they originate from, and the samples from the first two fermentation steps show the greatest difference, suggesting that multiple fermentation and distillation steps result in the end in similar volatile composition of the liquor. Back-propagation neural network (BNN) models were developed that satisfactorily predict the number of fermentation steps and the organoleptic evaluation scores of liquor samples from their volatile compositions. Mean impact value (MIV) analysis shows that ethyl lactate, furfural and some high-boiling-point acids play important roles, while pyrazine contributes much less to the improvement of the flavour and taste of Maotai-flavoured liquor during its production. This study contributes to further understanding of the mechanisms of Maotai-flavoured liquor production.

Characterization and comparison of the pungent components in commercial Zanthoxylum bungeanum oil and Zanthoxylum schinifolium oil.

In the present study, the characterization and comparison of the pungent components in commercial Z. bungeanum oils and Z. schinifolium oils were investigated. By high-performance liquid chromatography (HPLC)-mass spectrometry (MS/MS) analysis, the major alkylamides in Z. bungeanum and Z. schinifolium oils were identified as hydroxy-ε-sanshool, hydroxy-α-sanshool, hydroxy-ß-sanshool, hydroxy-γ-sanshool, hydroxy-γ-isosanshool, bungeanool, isobungeanool, and tetrahydrobungeanool, respectively. Hydroxy-α-sanshool was found to be the most abundant alkylamide in all oils. The levels of hydroxy-ε-sanshool and hydroxy-ß-sanshool in Z. bungeanum oils were comparable to that in Z. schinifolium oils, whereas Z. bungeanum oils contained significantly (P less than 0.05) higher levels of hydroxy-γ-isosanshool, bungeanool, isobungeanool, and tetrahydrobungeanool, compared with Z. schinifolium oils. Furthermore, principal component analysis (PCA) indicated that Z. bungeanum oil and Z. schinifolium oil were clearly classified by HPLC fingerprinting profiles and concentrations of alkylamides. In addition, the results of PCA suggested that alkylamides, such as hydroxy-γ-sanshool and bungeanool, could be potential markers to distinguish Z. bungeanum oil and Z. schinifolium oil. The results from this study could be used to discriminate the different flavor characterization and control the quality of commercial Z. bungeanum oil and Z. schinifolium oil.