Analysis of Differential Volatile Organic Compounds in Different Colored Millet Porridges by Gas Chromatography-Ion Mobility Spectrometry Combined with Multivariate Statistical Analysis

In order to explore the flavor characteristics of different colored millet porridges, the differences in volatile organic compounds in black, green, white and yellow millet porridges were analyzed by gas chromatography-ion mobility spectrometry (GC-IMS). The results showed that a total of 48 volatile organic compounds were identified from all samples, including 22 aldehydes, 11 ketones, 9 alcohols, 2 furans, 2 esters and 2 ethers, accounting for 68.58%-80.66%, 6.52%-9.89%, 5.99%-14.91%, 2.09%-5.66%, 1.13%-1.72% and 0.39%-0.69% of the total amount of volatile organic compounds, respectively. The major volatile organic compounds identified were aldehydes, alcohols and ketones, followed by furans, esters and ethers. The relative contents of aldehydes, ketones and esters in black millet porridge were higher, and the relative content of ketones in green millet porridge was highest. The relative contents of alcohols and furans in white millet porridge were highest. The relative contents of aldehydes and esters in yellow millet porridge were highest. Principal component analysis (PCA) and Euclidean distance analysis showed that the GC-IMS data of volatile organic compounds could be used to distinguish different colored millet porridge samples. A prediction model with good stability was established using orthogonal partial least squares-discriminant analysis (OPLS-DA), and 13 differential volatile organic compounds (variable importance in the projection (VIP) > 1) were identified, which could be used for classification of different colored millet porridges. This study provides useful information for enriching the eating quality characteristics of different colored millet.