Abstract: In this study, the aromatic components in potato flour incorporated instant congee processed with and without explosion puffing were investigated by solid phase microextraction (SPME) followed by gas chromatography-mass spectrometry (GC-MS) combined with principal component analysis (PCA). The results showed that the congee without explosion puffing treatment contained 50 aromatic components, 8 of which were the characteristic ones including hexanal, nonanal, 2-nonenal, phenylacetaldehyde, methylthiopropanal, 3-octen-2-one, furanone and 2,4-di-tert-butylphenol and most of which were hydrocarbons. The major aromatic compounds of the congee with explosion puffing treatment were heterocyclic compounds (especially pyrazines) and aldehydes, which gave the congee a roasted nut-like, burnt and unique potato-like flavor. According to PCA, the cumulative contribution rate of the three principal components to the total variance reached 90.758%, which reflected the changing trend of aromatic components in potato flour incorporated congee. PCA results showed that congees without and without explosion puffing treatment under different conditions of temperature and time (110 ℃/30 s, 130 ℃/30 s, 150 ℃/30 s, 170 ℃/30 s, 130 ℃/40 s, 130 ℃/50 s, and 130 ℃/60) were divided into four categories: 1) without explosion puffing, 2) 110 ℃/30 s, 130 ℃/30 s, 130 ℃/40 s, 130 ℃/50 s and 130 ℃/60 s, 3) 150 ℃/30 s , and 4) 170 ℃/30 s. Explosion puffing treatment had a certain effect on the overall flavor of potato incorporated congee, especially puffing temperature. At too high puffing temperature, a burnt flavor appeared as well as a darker color. Therefore, the optimal conditions for air puffing of potato incorporated congee were 150 ℃ for 30 s.

Key words: explosion puffing; potato incorporated congee; aromatic components; principal component analysis