Abstract: The major anthocyanins and flavonoids in red raspberry and mulberry were identified by ultraviolet-visible spectrophotometry and highperformance liquid chromatography-electrospray ionization-mass spectrometry. The effects of three different sterilization methods, including pasteurization (PS), boiling sterilization (BS) and microwave sterilization (MS), on the contents of total and individual anthocyanins, total phenols, major flavonoids and H2O2, and other physicochemical properties (pH, total soluble solid, absorbance, browning degree and transmittance) of red raspberry and mulberry juices were compared in the present study. The results indicated that major anthocyanins were cyanidin 3-sophoroside and cyanidin 3-glucoside in red raspberry, and cyanidin 3-glucoside and cyanidin 3-rutinoside in mulberry. Compared with the untreated juice, three sterilization methods reduced the contents of total and individual anthocyanins and total phenols , and MS treatment showed the weakest effect. No significant difference in the H2O2 level (P > 0.05) of sterilized juice was observed among different sterilization methods. Taken together, MS treatment could maintain the nutritional quality of red raspberry and mulberry juices.

Key words: highperformance liquid chromatography-electrospray ionization-mass spectrometry, anthocyanin, red raspberry and mulberry juices, pasteurization, boiling sterilization, microwave sterilization