Abstract:In order to select the suitable cooking methods for Brassica rapa L. (BrL), this study analyzed the effects of five cooking methods (boiling, steaming, microwaving, pressure cooking, and frying) on the nutrient and free amino acids (FAA) contents, antioxidant activities, and flavor characteristics of BrL using a food calorimeter (Calory Answer), an amino acid autoanalyzer, and an E-tongue. The results showed that the total FAA content of fresh BrL is 261.06 mg/100 g, with sweet amino acids dominating. The total FAA contents of BrL increased by 90.50%, 59.74%, and 83.92% by steaming, microwaving, and frying, respectively. The proportion of bitter amino acids also increased. Boiling increased the proportions of sour and umami amino acids and reduced the proportion of bitter amino acids. Frying, microwaving, and pressure cooking significantly increased the caloric value and carbohydrate content of BrL, whereas steaming and frying significantly increased the polyphenol content and antioxidant activity of BrL (P<0.05). E-tongue can be used to effectively evaluate the flavor differences of BrL samples treated with different cooking methods. The flavor of boiled and steamed BrL is similar. The flavor of microwaved and pressure cooked BrL is also similar. The taste of fried Brl greatly varied from that of the other BrL samples. Comprehensive evaluation based on principal component analysis (PCA) suggested that the most suitable cooking method for BrL is steaming, followed by frying.
