The effect of different processing methods on the physicochemical properties, volatile organic compounds and non-volatile metabolites of Turnip (Brassica rapa L.)

To investigate the effect of different processing methods on the quality of turnips, the alteration in physicochemical parameters, phenols, VOCs, and non-volatile metabolites were determined in turnips after steaming, boiling, and microwave heating. The results showed that steaming and microwaving improved the hypolipidemic, hypoglycaemic, and antioxidant activities of turnips and retained more active substances. Processing significantly affected amino acids and phenols, and the proportion of umami amino acids and coumaric acid increased. Sulfur-containing volatile compounds were significantly reduced and flavor improved. Microwaving increased the isothiocyanate content and retained the unique flavor of turnips. Untargeted metabolomics showed a significant increase in amino acids, organic acids, and nucleosides after processing, with the maximum difference in boiled samples. This study provides a theoretical foundation for the processing of turnips.