Relationship Between Chemical Markers and Sensory Score of Traditional Balsamic Vinegars Using a Screening Approach Combined with Rapid Assessment Methods

In this study, 200 samples of traditional balsamic vinegar (TBV) of Reggio-Emilia, a typical Italian aged dressing with Protected Denomination of Origin, were analyzed to model the relationship between sensory scores with some pre-selected compounds/parameters, such as Brix value, water activity (a (w)), titratable acidity, color, polymeric compounds, and electronic nose signal. Statistical techniques, such as nonlinear regression and Principal Component Analysis (PCA) were used to model the relationship among vinegars composition. The sensory score of panelists was mainly correlated with Brix (r = 0.85) followed by brown color at 445 nm (r = 0.74) and water activity (a (w)) (r = -0.79), whereas the polymeric compounds content showed a negative correlation with water activity (r = -0.73). In particular, the water activity of TBVs at different Brix values followed a nonlinear trend with good fitting (r = 0.857) with K = 3.10 that was consistent with the value reported in the literature for fructose and glucose. Electronic nose (enose) data from TBVs and six marker compounds (acetic acid, butyric acid, vanillin, ethyl-phenylacetate, phenylethyl alcohol, and furfural) combined with PCA revealed a pattern related to the ageing of TBVs.