高压二氧化碳对鲜榨梨汁贮藏稳定性的影响研究

研究了高压二氧化碳（HPCD）对梨汁中多酚氧化酶（PPO）酶活钝化效果、透明度、色泽和褐变度的影响,并分析贮藏期酶活、透明度和色泽稳定性。结果表明,经HPCD（30MPa-40℃-60min）处理后梨汁中PPO残存酶活为19%;其钝酶效果显著高于相同温度的热处理（p<0.05）,说明HPCD钝酶过程中温度和CO2形成的压力具有协同灭酶作用;且在4℃条件下贮藏8周也能较好抑制PPO酶活。HPCD处理能抑制贮藏期梨汁透光率降低和梨汁酶促褐变、保持鲜榨梨汁的色泽,对保持鲜榨梨汁品质贮藏稳定性有较好效果。90℃-10min热处理也能有效钝化PPO酶活,但是在高温加热过程中促进非酶褐变,并且使梨汁透光率下降,增大梨汁浊度,对梨汁品质保持不利。 

Study on effect of high pressure carbon dioxide on storage stability of fresh pear juice

The effect of high pressure carbon dioxide (HPCD) on polyphenoloxidase (PPO) activity, light transmission rate, color, browning degree of fresh pear juice were investigated, its storage stability was also analyzed.The result showed that the residual PPO activity was 19% as exposed to HPCD (30MPa- 40℃ for 60min) , which was much lower than that as exposed to thermal treatment at 40℃ for 60min, indicating that there was positive synergistic effect of temperature and pressure come from CO 2 during inactivation of enzyme by HPCD.The PPO activity was stabile during storage at 4℃ for 8 weeks.HPCD inhibited reduction of light transmission rate and browning, maintained excellent color, and obtained excellent quality during storage at 4℃ for 8 weeks.The PPO was also inactivated by thermal treatment at 90℃ for 10min effectively.Though nonenzymic browning was facilitated, light transmission rate was decreased, turbidity was accelerated by high temperature treatment, it was unfavourable for maintaining good quality of pear juice.