Quality assessment of Chinese liquor with different ages and prediction analysis based on gas chromatography and electronic nose

M L Xu,S M Zhu,Y Yu

doi:10.1038/s41598-017-06958-7

Abstract

The economic value of Chinese liquor is closely related with its age. Results from gas chromatograph (GC) analysis indicated that 8 dominant compounds were decreased with the increase of liquor age (0 to 5 years) while ethyl lactate was found to be the most stable dominant compound as no significant change was observed in it during the aging process. Liquor groups with different ages were well-discriminated by principal component analysis (PCA) based on electronic nose signals. High-accurate identification of liquor ages was realized using linear discriminant analysis (LDA) with the accuracy of 98.3% of the total 120 samples from six age groups. Partial least squares regression (PLSR) exhibited satisfying ability for liquor age prediction (R2: 0.9732 in calibration set and 0.9101 in validation set). The feasibility of volatile compounds prediction using PLSR combined with electronic nose was also verified by this research. However, the accuracies of PLSR models can be further promoted in future researches, perhaps by using more suitable sensors or modeling approaches.

Highlights

Chinese liquor is one kind of traditional alcoholic beverages with a long history of over 6000 years[1]
The main objectives of this study were: (1) to investigate the possibility of using electronic nose combined with principal component analysis (PCA) and linear discriminant analysis (LDA) to discriminate Chinese liquor with different ages; (2) to realize prediction analysis of liquor age and the contents of main volatile compounds in Chinese liquor based on response values and partial least squares regression (PLSR)
Hundreds of volatile compounds have been found in Chinese liquor by previous researchers, only the dominant compounds were selected in this work, since the main objective of this research was to explore the possibility of predicting volatile compounds contents using electronic nose signals

Summary

Introduction

Chinese liquor is one kind of traditional alcoholic beverages with a long history of over 6000 years[1]. Distilled liquors (young liquors) are often subjected to several months to years of aging to remove the undesired pungent flavor During this aging process, a series of complex physicochemical reactions such as oxidation, esterification and hydrolysis can take place along with the possible permeation of small and polar molecules through the ceramic jar[3, 4]. The main objectives of this study were: (1) to investigate the possibility of using electronic nose combined with principal component analysis (PCA) and linear discriminant analysis (LDA) to discriminate Chinese liquor with different ages; (2) to realize prediction analysis of liquor age and the contents of main volatile compounds in Chinese liquor based on response values and partial least squares regression (PLSR)

Objectives

Results

Conclusion