Comparison of flavonoids and phenylpropanoids compounds in Chinese water chestnut processed with different methods

Different processing methods of Chinese water chestnut (CWC; Eleocharis dulcis (Burm.f.) Trin. ex Hensch.) steaming with skin (WPC), cooking with skin (WPS), steaming with peeling (PS), fresh cutting (FF) and cooking with peeling (PC) were compared. Liquid chromatography-mass spectrometry was used to analyze the metabolic profiles of the processed samples. A total of 454 metabolites, including 123 flavonoids and 57 phenylpropanoids, were characterized. The flavonoid and phenylpropanoid profiles were distinguished using PCA. Eighteen flavonoids and six phenylpropanoids were detected and quantitated in the WPC and WPS samples but not in the FF, PC and PS samples. In addition to the O-hexoside of tricin, kaempferol and luteolin were the predominant flavonoids in the WPC and WPS samples, and all three compounds were higher in the WPC and WPS samples than in the FF sample. This study provides new results regarding differences in the metabolite profile of CWC processed with different methods.