| As one Chinese traditional alcohol beverage, Chinese liquor has a long brewing history in China. In the long development of Chinese liquor, its unique brewing process and style characteristics has been formed. There are six top distilled liquors in the world, and Chinese liquor is among of them. In recent years, with the quick development of Chinese liquor industry, Chinese liquor adulteration in regard to aged liquor and geographic origin exists extensively. Chromatography, spectroscopy and other analytical methods can be used to qualitative and quantitative analysis of compounds of Chinese liquor. However, these methods need to use expensive and large-scale instruments, and detection procedure is time-consuming. So they cannot be applied in real-time detection in the field of circulation. Due to deficiency of liquor detection technology, visualization bionic olfactory system was designed to identify liquor. In this research, visualization bionic olfactory system combined with pattern recognition was applied to discriminate aged liquor and to classify Chinese liquor from different geographic origins. The main works were listed as follows:(1) Visualization bionic olfactory system was designed and manufactured to identify Chinese liquor. This system was composed of gas generator equipment, gad detection equipment, heating equipment, dynamical system, and control and date acquisition system. Gas generator equipment was used to generate volatile gas. Gas detection equipment included colorimetric sensor array, image acquisition system and light source. Control and date acquisition system was used to control system and processing data. This integration system realized the sampling, scanning images, processing data and samples of identification quickly.(2) Gas chromatography-mass spectrometry (GC-MS) was used to determine the 12 volatile compounds. One way analysis of variance (ANOVA), principal component analysis (PCA) and linear discriminant analysis (SLDA) were applied to process data obtained by GC-MS and to develop discriminant models. ANOVA showed that ethyl acetate, ethyl butyrate, ethyl lactate, ethyl caproate, 1-propanol, 2-butanol, 1-butanol, isopentanol, isobutanol, 1-hexanol, methanol were most correlated with aged liquor. The data was analyzed by pattern recognition (PCA, LDA). LDA showed that a 96.4% of recognition capability for aged liquor, and the prediction ability of aged liquor was 96.4%. The results suggested that volatile compounds express the characteristic information of aged liquor.(3) Visualization bionic olfactory system was used for quantitative detection of aroma compositions in Chinese liquor, such as alcohols, acids, esters and aldehyde. The results demonstrated that different concentrations of aroma composition provided special color change profiles. Difference between different concentrations could be observed by visual inspection of color change profiles. The digital date library generated was analyzed with Hierarchical cluster analysis (HCA). Using a HCA dendrogram, alcohols, acids, esters and aldehyde were correctly distinguished and this system showed a good reproducibility and repeatability. In addition, Visualization bionic olfactory system was succeeded to identify the adulterated liquor by observing color change profiles. The results showed the potential application of visualization bionic olfactory system for monitoring quality, discriminating aged liquor and geographic origins.(4) The interaction between porphyrin (TPPS4, ZnTpp) and alcohols, acids, esters, furfural was analyzed by molecular docking. Total-score, Crash, Polar and Cscore were used to describe results. Complex conformation showed that the interaction between TPPS4 and alcohols, acids, esters, furfural was via hydrogen bond. The interaction between ZnTpp and alcohols, acids, esters was via coordinate bond, while ZnTpp interacted with furfural was viaπ-πeffect. This paper provided a new method to study the interaction between porphyrin and aroma composition of Chinese liquor.(5) Visualization bionic olfactory system was applied to discriminate aged liquor. Comparing with color change profiles of aged liquor, it was found that different aged liquor provided special color change profiles as unique fingerprints for each one. The digital data library generated was analyzed with pattern recognition, including PCA, HCA and LDA. PCA and HCA analysis showed that visualization bionic olfactory system can distinguish different aged liquor. LDA model showed a 100% of recognition capability and 93.8% prediction ability for aged liquor. This system was also used in discriminating based liquor. The developed visualization bionic olfactory system showed a unique pattern of color change to different aged liquor. The RGB values of the colorimetric sensor array were analyzed by pattern recognition method, including HCA, PCA and LDA. HCA and PCA suggested different based liquor can be easily discriminated by visualization bionic olfactory system. Certain regularity showed in HCA, it was useful to distinguish based liquor of unknown year. LDA analysis showed a 100% recognition capability and prediction ability for based liquor. These results suggested that visualization bionic olfactory system might provide a rapid and practicable method for detection Chinese liquor.(6) Visualization bionic olfactory system was used to characterize and identify strong aroma style Chinese liquor and light aroma style Chinese liquor from different geographic origins. Colorimetric sensor array before and after exposure to Chinese liquor provided unique color change profiles as fingerprint characteristic information for Chinese liquor from different geographic origins. Data analysis was performed by pattern recognition: Hierarchical cluster analysis (HCA), principal component analysis (PCA) and linear discriminant analysis (LDA). LDA model showed a 100% of recognition capability and prediction ability for Chinese liquor. The results showed that visualization bionic olfactory system was able to classify Chinese liquors from different geographic origins. Differentiation between samples was observed by visual inspection of color change profile. This method provides an important reference for constructing of Chinese liquor fingerprint database. |
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