Fig. 3

Multivariate statistical analysis of volatile aroma compounds (VACs) during fermentation of cigar tobacco leaves. (A) Score scatter plot for the principal component analysis (PCA) model (PE). (B) Hierarchical clustering analysis and heatmap visualization of VAC profiles at different fermentation stages of PE cigar tobacco leaves. (C) Important characteristics of different locations (DH, PE and LC) before and after fermentation identified by OPLS-DA. The colored boxes on the right indicate the relative concentrations of the VACs in each group under study. (D) The potential markers responsible for the aroma differences among DH, PE and LC. The screening criteria were VIP > 1 and FC > 1.