Ultrasonic and other sterilization methods on nutrition and flavor of cloudy apple juice

Sterilization plays an important role in extending the shelf-life of apple juice; however, it also affects the nutritional and flavor profile of the juice. This study was initiated to evaluate the effects of several common sterilization methods (conventional pasteurization, microwave sterilization, ultrasonic sterilization, and ultra-high-pressure sterilization) on some important quality parameters of apple juice. The results showed that the content of soluble pectin and soluble protein in juice decreased significantly after ultra-high-pressure sterilization. Sonication was found to be effective in increasing the level of ascorbic acid in apple juice. The sugar:acid ratio increased significantly after pasteurization, microwave sterilization, and ultra-high-pressure sterilization, which changed the taste of juice. Microwave sterilization caused the highest volatile compound loss, while ultra-high-pressure sterilization led to a higher retention rate of volatile compounds in juice. This study could be helpful in seeking suitable sterilization methods retaining the quality of cloudy apple juice.