Evaluation of guava during different phases of the industrial processing.

In this work we studied the contents of pectin and protein, pectinmethylesterase (PME) activity, and PME stability in various stages of industrial processing, due to the implication of these values on the quality of the final product. The results of the PME stability at different values of pH showed residual PME activity at alkaline pH (7.0, 8.0, 8.5 and 9.5) and high stability at pH 4.0. These results show that pH treatment is not an efficient method to inactivate the PME enzyme. The presence of residual PME activity in all steps of industrial processing was also verified, showing that PME can change the quality of the pulp during storage.