PCA and HCA were performed using Unscrambler version 9.7 (CAMO ASA, Oslo, Norway) to analyze the relationship between different SFFPs samples based on volatile compounds and sensory properties.
The sensory characteristics of SFFPs including saltiness, sourness, bitterness, sweetness, umami, richness, and overall acceptance were evaluated.
Volatile Compounds and Their Contribution to the Aroma Characteristics of SFFPs. A total of 96 volatile compounds were detected by GC-MS coupled with SPME (supplementary Table S1) and were subdivided into different classes, including 12 acids, 17 alcohols, 23 aldehydes, 33 esters, four ketones, three nitrogenous compounds, and four lactones.
Among the detected alcohols, 2-methyl-1-butanol, 3-methylthiopropanol, 2-methyl3- phenyl-2-propen-1-ol, and 3-furanmethanolmight make significant contributions to the aroma of SFFPs because of their low threshold values [31, 32].
However, from the aroma composition and sensory characteristic results, it could be speculated that the overall taste and aroma of SFFPs were dependent on particular components, such as the "critical balance" and "weighted concentration ratio" of all the present components.
To simplify the interpretation of relationships between volatile compounds detected by GC-MS and sensory attributes in the different samples, PCA was carried out with 96 volatile compounds and the sensory attributes of the seven SFFPs samples.
In the present study, different data fusion strategies were used to discriminate the flavor difference among SFFPs to understand the potential correlation between the sensory profiles and volatile compounds.
Abbreviations HCA: Hierarchical cluster analysis PCA: Principal component analysis PLS-DA: Partial least squares-discriminant analysis SPME-GC-MS: Solid-phase microextraction gas chromatography mass spectrometry SFFPs: Sweet fermented flour pastes.
Concentration of volatile compounds of seven SFFPs by GC-MS (means (n = 2), [micro]g/g).
Caption: Figure 1: Radar plot of the SFFPs sensory descriptors, as assessed by trained panelists for each attribute.
Caption: Figure 2: The compositions of volatile compounds in SFFPs. Bars show the mean ([+ or -]SD) of duplicate analysis from GC-MS data.
Caption: Figure 3: Dendrogram from the hierarchical cluster analysis using centroid clustering of seven SFFPs samples with the relative abundances of 96 volatile compounds as variables.