Apple juice processing enzyme treatment

Quoc et al (2006) studied the development of a process that permitted quick inactivation of PME, which is present in cloudy or unclarified apple juice. This enzyme is responsible for opalescence instability. In order to achieve this objective, acidification of the apple juice to pH 2.0 was performed by electrodialysis, followed by mild heat treatment at temperatures of 40,45, and 50°C for 0-60 minutes. Opalescence of the adjusted juice was more stable than for an untreated cloudy apple juice when stored at 4°C for 3 months. 

Figure 5. Effect of processing and storage on the phenolics of Granny Smith apple juice. Unit operations code P, pressed juice H, heat treatment E, enzyme clarification F, fined NF, not fined Ft, filtered B, bottled single-strength juice C, concentrate and CS, stored concentrate.

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