Effect of Extrusion Temperature on Characteristic Flavor Compounds in Pea Flour

In order to explore the effects of extrusion processing on characteristic flavor compounds of pea flour and improve the flavor quality, in this study, electronic nose(E-nose) and gas chromatography-ion mobility spectrometry(GC-IMS) were used to investigate the effects of extrusion temperatures (120, 150, 180 ℃) on volatile flavor compounds of pea flour and compared with unextruded pea flour. The flavor differences between samples with different extrusion temperatures can be evaluated objectively by the electronic nose system. A total of 53 volatile substances in 8 compounds, including aldehydes, alcohols, ketones, acids, esters, pyrazines, furans and ethers were identified by GC-IMS. The relative content of alcohols, ketones, acids, esters, ethers decreased, the relative content of pyrazines and furans increased. The relative content of characteristic beany flavor compounds such as trans-2-octenal, hexanal, 1-octene-3 alcohol, n-hexanol, 1-pentanol, n-butanol and 2-pentylfuran decreased by 23.53%, 33.23%, 50.44%, 88.82%, 77.69%, 84.51%, 26.19%, respectively and the relative content of 2, 5-dimethylpyrazine, 2-methylpyrazine and 2-furanmethanol with roasted flavor increased by 16.16, 23.92, and 7.95 times, respectively at the extrusion temperature of 180 ℃. Relative odor activity value (ROAV) showed that n-nonanal, 3-methylbutanal, hexanal, n-octanal, 1-octen-3-ol, heptanal, ethyl acetate, n-butyraldehyde, trans-2-octenal, 2-pentylfuran, 2-ethylfuran and n-hexanol were the characteristic flavor compounds of raw pea flour. Principal component score determined that the flavor of the 180 ℃ extruded sample was the best.