Research Article

Metabolomic Biomarkers Differentiate Soy Sauce Freshness under Conditions of Accelerated Storage

Figure 2

Heat map of correlations between sensory terms affected by storage time and metabolites. Heat coloring denotes the strength and direction of the correlation based on the Kendall correlation coefficient scale. Metabolites with significant correlations () to one or more sensory terms were split into five groups based on hierarchical clustering denoted by the color bars orange, yellow, green, blue, and gray. Sensory variables were similarly grouped by hierarchal clustering based on correlations with metabolites (a). Identified metabolites associated within each hierarchical cluster (b). Unidentified features are not listed and sugar molecules are only confidently assigned at a molecular class level and are differentiated by chromatographic retention time. For each cluster, the changes in abundance for cluster members (molecules) are plotted over time as log2 of the fold change from time 0 month (c–g). The members of the yellow cluster have the greatest change over time.
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