Figure 1.

Hierarchical cluster analysis performed using metabolite profiles of balsamic vinegars. The heatmap was generated using 70 most significant metabolites (p-value < 0.05) by a Ward algorithm and Euclidean distance analysis. IGP denotes the samples certified as Protected Geographic Indication to indicate their premium quality, while non-IGP samples are regular commercial vinegar samples. Here, D = Delmaine^TM, L = Lupi^TM, M1 = Mazetti^TM one leaf, M4 = Mazetti^TM four leaves, P = Pam’s^TM and T = Tastemaker^TM, 5-HMF = 5-Hydroxymethylfurfural, p-HCA = p-hydroxycinnamic acid, 2-MBA = 2-methylbutyric acid, 4,4-DE-3M-2-O = 4,4-Diethyl-3-methylene-2-oxetanone, 2-EHA = 2-Ethylhexanoic acid, 5-HM-2-F = 5-Hydroxymethyl-2-furaldehyde, NALG = N-Acetyl-glutamate, EHS = Ethylhydrogen succinate, 1,3-PDA = 1.3-Propylene diacetate, MSA=Methylsuccinic anhydride, 1,3-DAOP = 1,3-Diacetoxypropane, 2-M-1-BA = 2-Methyl-1-butyl acetate, 3-M-1,2-CPD = 3-Methyl-1,2-cyclopentanedione, 4-M-2-PDA = 4-Methyl-2-pentanoic acid, 2-ABA = 2-Aminobutyric acid.