Comparison of the effects of novel processing technologies and conventional thermal pasteurisation on the nutritional quality and aroma of Mandarin (Citrus unshiu) juice

Conventional thermal pasteurisation (90 degrees C and 30 s), high pressure processing (HPP: 600 MPa, 4 degrees C and 300 s), ultrasound processing (US: 50 degrees C, 750 W and 36 min) and microwave processing (MW: 800 W, 80 degrees C and 70 s) were evaluated by examining their effects on the sensory and nutritional qualities of mandarin juice. The treated samples had < 2 log CFU/mL total aerobic bacteria, which is equivalent to microorganism inactivation. Sugar and acid components were almost constant for all the treated mandarin juices, and no differences between treatments were perceptible. However, the mandarin juice treated with novel technologies maintained better colour (L*, a* and b*), nutritional value (ascorbic acid, total phenolic, total carotenoid content and phenolic components) and aroma than the thermally pasteurised one. This study showed that US, MW and HPP are good novel processing techniques to inactivate microorganisms and maintain the sensory and nutritional quality of mandarin juice.