Abstract: In this study, quinoa was processed in three different ways: roasting, extrusion and steaming. Sensory evaluation and headspace solid phase micro-extraction followed by gas chromatography-mass spectrometry (HS-SPME-GC-MS) combined with relative odor activity were used to investigate the main volatile flavor compounds of the processed quinoa. The results showed that the different heat treatments had different effects on the flavor of quinoa. Benzene acetaldehyde, (E)-2-octenal, nonanal, (E)-2-nonenal, and decanal were found to be the key flavor substances in all thermally processed quinoa samples. (E,E)-2,4-nonadienal was the unique key flavor compound of steamed quinoa, while benzeneacetaldehyde contributed greatly to the cooked peanut-like flavor of roasted quinoa. The volatile compounds of quinoa with different heat treatments were further analyzed by principal component analysis (PCA). It turned out that extrusion and steaming had great influence on the volatile flavor substances of quinoa. In addition, each of the three treatments could reduce the bitterness of quinoa, which was associated with reduced saponin content as determined by high performance liquid chromatography (HPLC). This study provides a theoretical basis for the processing of quinoa.

Key words: quinoa; heat treatment; flavor; bitterness; saponins