Objective The study was carried out to explore the changes of volatile flavor components of Guangshu 87 before and after steaming with a view to providing a basis for the improvement of fresh sweetpotato flavor substance.

Method The headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) technology were used to compare and analyze the volatile flavor components of fresh and steamed Guangshu 87.

Result A total of 71 volatile compounds were detected in fresh Guangshu 87, mainly including aldehydes (40.52%), terpenoids (16.18%), heterocycles (15.17%), alcohols (11.59%), esters (7.94%), aromatics (4.49%), ketones (1.62%), and etc. A total of 69 volatile compounds were detected in steamed Guangshu 87, mainly including aldehydes (47.36%), aromatics (21.39%), terpenoids (10.33%), halogenated hydrocarbons (7.07%), alcohols (3.24%), ketones (2.64%), esters (2.61%), and etc.. Among them, the volatile compound with the highest relative content in fresh and steamed sweet potato was phenylacetaldehyde, with the relative content of 16.78% and 19.92%, but there was no significant difference in it before and after steaming. Differential analysis showed that a total of 47 differential metabolites were screened, in which 14 were up-regulated and 33 were down-regulated. The compound with the highest up-regulation factor was chloro-acetic acid, 2-phenylethyl ester with an up-regulation factor of 4.4, and the compound with the highest down-regulation factor was 2-propyl-1H-imidazole, with the down-regulation factor as high as 13.49.

Conclusion Combining the relative content and differential analysis, the main volatile components with a significant increase in the relative content of Guangshu 87 after steaming are 2, 4-Di-tert-butylphenol and chloro-acetic acid, 2-phenylethyl ester, which are the most likely constituents of the characteristic volatile flavor of steamed Guangshu 87.