Extraction and characteristics of polyphenol oxidase from white shrimp

The optimization of extraction and biological characteristics of polyphenol oxidase（ PPO） of white shrimp（ Penaeus vannamei） were studied. The experimental factors and levels were determined by single factor experiments. Response surface methodology was used to explore the effects of solid-liquid ratio，pH and extraction time on PPO activity. The results showed that the optimal extraction conditions were as follows: the solid-liquid ratio was 2∶1，pH was 8.0 and the extraction time was 3.0 h. Under the optimal extractions，the PPO activity could reach 94.8 A/min·mL. Regressive model of extracted PPO was significant（ P ＜ 0.0001） and better fitting（ R2=0.9762）， it could be used to predict the PPO extraction. The kinetic equation of enzyme reaction was consistent with Michaelis Menten equation. The Km was 30.322 mmol/L and Vmax was about 0.281 A/min. Study on properties of PPO could provide theoretical guidance for white shrimp anti-melanosis technology.