Refining Reduced the Number and Content of Compounds of Soybean Oil

ABSTRACT To explore the effect of the refining process on the compounds of soybean oil, three different refined grade soybean oils were detected by ultra performance liquid chromatography‐high‐definition mass spectrometry and chemometrics for finding the differential compounds. The results of PCA and PLS‐DA showed that three different refined grade soybean oils had the clear separation trend and the number and content of compounds in soybean crude oil (SCO) gradually reduced with the increased process of the refining. Our result indicated that the refining processes reduced the number and content of compounds in SCO. The decreased trans fatty acids and other unfavorable quality compounds (free fatty acids) suggested that the refining process was necessary. But, 108 compounds with potential function in SCO were significantly reduced during the process of the refine. Most of these compounds (daidzein, linoleamide, and stearamide, etc.) were reduced during the process of the third‐grade refine and were even not detected after the first‐grade refine. In addition, 16 compounds were not found in SCO and were detected in the refined soybean oil and increased during the refining processes. Our results suggest that refining diminishes the quantity and concentration of compounds with potential function in SCO and should be improved.