金属离子辅助高静压钝化树莓多酚氧化酶研究

 树莓多酚氧化酶具有较强的耐压性，在600 MPa压力下处理45 min，其残余酶活仍高达40%以上。为了进一步钝化树莓内源多酚氧化酶的活性，研究了金属离子辅助高静压对树莓多酚氧化酶钝化的影响。在树莓多酚氧化酶粗酶液中添加对酶活性有抑制、激活、无改变的金属离子，研究其辅助400、600 MPa压力处理钝化树莓多酚氧化酶的效果。发现添加金属离子后，多酚氧化酶的活性随压力增大、时间延长而降低；Fe²⁺、Mn²⁺以及Cu²⁺均有不同程度的协同高静压钝化作用，而Ca²⁺在钝化树莓多酚氧化酶时与高静压出现拮抗现象，对树莓多酚氧化酶活性无影响的Zn²⁺未出现协同/拮抗作用。

Effect of Pressure Combined with Metal Ions on Polyphenol Oxidase (PPO) Activity from Raspberry

The activity of polyphenol oxidase from red raspberry treated at 600 MPa for 45 min is even up to 40%, indicating strong pressure resistance. In order to further inactivate polyphenol oxidase from red raspberry, the combination effect of high hydrostatic pressure and metal ions on polyphenol oxidase activity was investigated. The change of polyphenol oxidase activity treated at 400 and 600 MPa after adding metal ions was revealed. The activity of raspberry polyphenol oxidase gradually decreases with the pressure increasing and/or the holding time extending with/without adding metal ions. Fe²⁺, Mn²⁺ (both inhibited polyphenol oxidase) and Cu²⁺ (activated polyphenol oxidase) in combination with pressure have synergistic effects, Ca²⁺ (inhibited polyphenol oxidase) combined with pressure has antagonistic effect, and Zn²⁺ (not change polyphenol oxidase activity) has no synergistic/antagonistic effect.