Abstract
Green coconut water preserved by UHT sterilization can be rejected due to a pinkish color forming during storage. This work aimed to evaluate the UHT temperature effect on pinkish color formation and if it is related to polyphenol oxidase (PPO) or peroxidase (POD) enzyme activities. Experiments were carried out with UHT sterilization followed by aseptic filling and storage at room temperature. With the use of UHT temperatures (142, 138, 120 and 110°C), the heat treatment inactivated the PPO and POD enzymes and did not show immediate changes in color, but after 24 h storage, only sub-processed samples (120 and 110ºC) presented pink coloration. The subprocessing treatment at 110 ° C / 8s and without the addition of sulfite, showed samples with a pink color after 24 h of processing. The pink color was not related to the enzymatic activity, and the sodium metabisulfite was effective in avoiding the pink color in the under-processing condition (110 ° C / 8s). Results of another experiment at 136°C and 110°C, a pink coloration was only observed in the treatment performed at 110°C, and no regeneration of POD or PPO activities were observed. The pink color in the UHT sub-processing treatments was not related to the enzymatic activity.
