Abstract: This study aimed to explore the effect of variable-temperature variable-pressure puffing on the umami and aroma components of Pleurotus geesteranus. High performance liquid chromatography, an amino acid analyzer, an electronic tongue, headspace solid phase microextraction and gas chromatography-mass spectrometry (GC-MS) were used to determine the aroma and taste compounds. The results showed that the umami amino acid contents of fresh, pre-dried and puffed samples were 2.941, 8.820 and 3.759 mg/g, respectively; the flavor nucleotide contents were 0.220, 0.850 and 1.278 mg/g, respectively. The equivalent umami concentration (EUC) values were 1.839%, 27.211%, and 9.687%, respectively. A total of 29 volatile flavor components were identified from fresh, pre-dried and puffing samples, including alcohols, aldehydes, ketones, alkanes and furans. The three samples contained 18, 16 and 13 volatile flavor components, respectively. After variable-temperature variable-pressure puffing, the contents of umami components increased; the relative contents of aldehyde, olefin and furan compounds increased, while the relative contents of alcohols and ketone decreased. In summary, variable-temperature variable-pressure puffing can enhance the umami taste of P. geesteranus, and the contents of hexanal and benzaldehyde increase after puffing, which have a green grass and almond-like aroma, contributing to the unique aroma of puffed P. geesteranus. Variable-temperature variable-pressure puffing is a suitable processing method for P. geesteranus.

Key words: Pleurotus geesteranus, variable-temperature variable-pressure puffing, umami, aroma