Effects of sonication and carbonation on guava juice quality

The effects of carbonation and sonication on the quality of guava juice were studied for selected physicochemical properties such as colour, cloud stability, pH, acidity, total soluble solids, polyphenoloxidase (PPO) activity, ascorbic acid content and microbial stability. Ascorbic acid content was found to be significantly (P < 0.05) higher in samples treated with carbonation and sonication than in the control. It is suggested that carbonation provides more nuclei for cavitations that permit the elimination of dissolved oxygen in the juice. In addition, such a treatment also gave rise to a greater cloudiness and PPO activity, which could be attributed to the production of a stabilized colloid system due to smaller particle size and higher phenolic compounds availability, respectively. Nevertheless, sonication, coupled with carbonation, was not an efficient treatment for microbial inactivation at room temperature.