Criegee mechanism as a safe pathway of color reduction in sugarcane juice by ozonation

- Ozonation is a healthier alternative capable to remove color replacing sulfur.
- Ozone breaks the benzene ring structure of phenolic groups.
- The Criegee mechanism is one of the steps to the oxidation of gallic acid.
- Ozone does not promote degradation of sucrose in the optimum conditions.

The production of crystal sugar is based on sugarcane juice clarification through sulphitation, that is, heat treatment with sulfur dioxide. The use of ozonation as an alternative to sulphitation aims to eliminate the disadvantageous presence of residual sulfite in crystal sugar. Both treatments are used to reduce color of sugarcane juice. The objective of this work was to evaluate two process parameters (temperature and pH) to reduce gallic acid, a low molecular weight pigment (MW 170 g mol−1) widely found in sugarcane. Gallic acid was used as a model compound in sucrose solutions. The results showed that degradation of gallic acid was favored from pH 7.0 to 7.82 and temperature values between 50 and 70 °C. The reaction mechanism was proposed for gallic acid degradation by ozone based on Criegee mechanism. Ozonation was an efficient method to reduce the potential low molecular weight pigment present in the sugarcane.

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