Chemical composition, enzyme activity and effect of enzyme inactivation on flavor quality of green coconut water

Differences in mineral content among fresh untreated, high pressure carbon dioxide treated, and heat pasteurized coconut water were attributed to lipids present in coconut water as emulsions.

“These differences were attributed to lipids that, even in a small amount, were present in coconut water as emulsions (Campos et al. 1996; Jackson et al., 2004).”

At 90 °C, total inactivation of PPO was obtained after 550 s and of POD after 310 s.

“At a low temperature (90 °C), total inactivation was obtained after 550 s for PPO and after 310 s for POD [50].”

Adding nisin, ascorbic acid, or citric acid and sodium metabisulphite to pasteurised coconut water gave efficient results.

“Efficient results were obtained by adding molecules such as nisin [43], ascorbic acid [50] or citric acid and sodium metabisulphite [74].”

With additives, pasteurised coconut water could be preserved for 2 to 3 months at ambient temperature or refrigerated.

“In these cases only, it was possible to preserve pasteurised coconut water for 2 to 3 months at ambient temperature or refrigerated.”

At temperatures above 77 °C, PPO was found to be more thermally resistant to microwave heating than POD, corroborating the results of Campos et al.

“At temperatures above 77 °C, PPO was found to be more thermally resistant to microwave heating than POD, corroborating the results of Campos et al. [50].”

Optimum activities of polyphenoloxydase (PPO) and peroxydase (POD) in green coconut water occurred at pH 6.0 and pH 5.5 and at temperatures of 25 °C and 35 °C, respectively.

“Optimum activities of polyphenoloxydase (PPO) and peroxydase (POD) in green coconut water occurred at pH 6.0 and pH 5.5 and at temperatures of 25 °C and 35 °C, respectively [44].”

PPO and POD are the major browning enzymes responsible for changes in the sensory and nutritional quality of TCW.

“Polyphenol oxidase (PPO) and Peroxidase (POD) are the major browning enzymes that are responsible for changes in the sensory and nutritional quality of TCW (Campos, Souza, Coelho, & Gloria, 1996;Duarte, Coelho, & Liete, 2002).”

PPO uses polyphenol as a substrate and through rapid polymerization of O-quinones produces brown, black, or red pigment.

“PPO uses polyphenol as a substrate and through rapid polymerization of O-quinones produces brown, black, or red”

POD catalyses phenolic oxidation reactions to produce browning.

“pigment, whereas POD catalyses phenolic oxidation reactions to produce browning (Campos et al., 1996;Zhang, Pang, Xuewu, Ji, & Jiang, 2005b).”

Complete inactivation of PPO and POD was observed at higher temperature treatment (90°C) after 550 s and 310 s, respectively.

“However, complete inactivation of PPO and POD was observed at higher temperature treatment (90°C) after 550 s and 310 s, respectively, (Campos et al., 1996).”