Optimization of pectinase and protease clarification treatment of pomegranate juice

- Pomegranate juice was treated with pectinolytic and proteolytic enzymes.
- Time, temperature and complex enzyme concentration were optimized by RSM.
- Complex enzyme concentration was the most important factor influencing the clarity.
- Protease-pectinase treatment caused a loss of haze active proteins and phenols.

Clarification is a fundamental step in the processing of pomegranate juice to improve its appearance and marketability. The objective of this work was to develop a tailored pectinolytic and proteolytic enzymatic clarification process for pomegranate juice. Response surface methodology was used to analyse the effects of incubation time (30-120 min), temperature (25-50 °C) and complex enzyme amount (0.1-0.4 g/100 g of juice) on physical characteristics of pomegranate juice. R2 and adjusted R2 for chill haze, turbidity, potential turbidity and clarity regression models were greater than 0.9 and 0.8, respectively. The complex enzyme amount was the most important factor influencing the clarification of pomegranate juice. Moreover, it was found that an increase of the complex enzyme amount caused a substantial loss of protein and phenol haze forming activity. The optimum enzymatic treatment conditions were: temperature 25-30 °C, time 100-110 min, protease-pectinase complex enzyme amount (the ratio of protease:pectinase was 1:2) 0.22-0.25 g/100 g of pomegranate juice.