Physicochemical indexes and flavor quality analysis of 4 commercial vinegars

Taking 4 commercial vinegars (samples LV, ZV, SV, and BV) as the research objects, the sensory evaluation, basic physicochemical indexes, volatile flavor compounds, and non-volatile compounds were analyzed, cluster analysis (CA) and partial least squares-discriminant analysis (PLS-DA) were carried out based on detection results, and the differential flavor substances (variable importance in the projection (VIP) values>1) were determined. The results showed that the sample LV had the highest score of sweetness, saltiness and acceptability. The soluble solid and reducing sugar contents of sample ZV were the highest, which were 10.26 g/100 ml and 1.9 g/100 ml, respectively. The GC-MS showed that the types and relative contents of volatile flavor compounds in samples BV and LV were the highest, respectively, which were 66 and 165.5 mg/kg, respectively. CA results showed that the common compounds such as methyl acetate and phenylethyl acetate were relatively high in sample LV. The contents of total polyphenols and total organic acids in sample BV were the highest, which were 1.55 mg/ml and 19.54 mg/ml, respectively. The total flavonoids contents in sample ZV were the highest, which were 0.41 mg/ml. PLS-DA results showed that the samples BV, ZV, LV and SV were positively correlated with 5-methylfurfural, diethyl succinate, acetoin and trimethylpyrazine, respectively. The differential flavor substances affecting the vinegar flavor were ethyl acetate, phenylethyl acetate and furfural, etc.