Apple grinding technology with liquid nitrogen injection to exclude oxygen and lower temperature

To control the browning in apple juice processing, new grinding equipment was designed by using liquid nitrogen to exclude oxygen and lower temperature, the changes of fruit slurry's temperature, the content of dissolving oxygen(DO) and the color were systemically studied, as well as the activity changes of polyphenoloxidase(PPO) and peroxidase(POD) during grinding. Results show that after adding 1%～2% liquid nitrogen, the temperature of fruit slurry reduce to 50% of the original one, and the content of oxygen in the fruit slurry is only 47.7% of the original one; while the L ratio is 53.96 which is 44.1% higher than the original figure, meanwhile the loss of vitamin C will be reduced greatly and the juice yield will be improved.