Monitoring vinegar acetic fermentation using a colorimetric sensor array

This paper attempted a portable colorimetric sensor array to monitor vinegar acetic fermentation. We fabricated a colorimetric sensor array by printing 15 chemically responsive dyes (i.e. 9 porphyrins/metalloporphyrins and 6 pH indicators) on a C2 reverse silica-gel flat plate. The colorimetric sensor array, with specific colorific fingerprint to the VOCs in vinegar, was successfully used to monitor vinegar acetic fermentation with the help of multivariate calibration. Principal component analysis (PCA) and linear discriminant analysis (LDA), as two multivariate calibration tools, were used to classify vinegar samples at different acetic fermentation stages. Experimental results show that LDA achieved a better result and its classification rate is 100% by leave-one-out cross-validation (LOOCV). Besides, we systemically studied the change of VOCs during vinegar acetic fermentation with the help of hierarchical cluster analysis (HCA). This research work shows that the colorimetric sensor technique has a potential in monitoring vinegar acetic fermentation.