Characterization and comparative study of flavor profiles of soy, pea, mung bean, chickpea, faba bean, and peanut proteins using GC‐E‐nose, HS‐SPME‐GC‐MS, and HS‐GC‐IMS

Plant proteins, especially legume proteins, have garnered widespread attention due to their rich nutritional value and numerous health benefits. In this study, the flavor properties of soy, pea, mung bean, chickpea, faba bean, and peanut proteins were analyzed and compared using rapid gas chromatography electronic nose (GC-E-Nose), headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS), and headspace gas chromatography-ion mobility spectrometry (HS-GC-IMS) coupled with chemometrics. GC-E-Nose analysis showed a distinct difference in the volatile compounds of six legume proteins. A total of 208 and 101 volatile compounds were identified using GC-MS and GC-IMS, respectively, with aldehydes, alcohols, and ketones being the main volatile components. Among the six legume proteins, chickpea protein possessed the highest content of volatile compounds, whereas peanut protein contained the largest number of volatile compounds. In the meanwhile, 40 and 33 compounds with variable importance in the projection (VIP) greater than 1 were screened using orthogonal partial least squares discriminant analysis (OPLS-DA), of which 15 (hexanal, nonanal, 2,6-dimethylpyrazine, heptan-2-one, 2,5-dimethylpyrazine, pentan-1-ol, tridecane, tetradecane, oct-3-en-2-one, 1,4-xylene, hexanoic acid, dodecane, 2-pentylfuran, hexan-1-ol, pentanal), and 3 (propan-2-ol, heptan-2-one-D, pentan-1-ol-D) compounds with VIP > 2, respectively. These volatiles were the key differential compounds that distinguished the six legume proteins. GC-MS combined with odor activity value (OAV) identified 35 flavor compounds as key odor active compounds with OAV > 1. The combined application of these techniques better characterized the flavor profile differences among legume proteins, providing theoretical guidance for developing new plant-based alternative protein products.