Objective: Polyphenol oxidase or PPO (EC 1.14.18.1) is considered the enzyme responsible for quality deterioration and browning in different fruits during postharvest period. The objective of this study was to evaluate the antibrowning (inhibition of polyphenol oxidase activity) effect of Cysteine, Ascorbic acid, citric acid, kojic acid and glycine at two different pH (6 and 7) in  hawthorn. Me...

Polyphenol oxidase of leaves is located mainly in chloroplasts isolated by differential or sucrose density gradient centrifugation. This activity is part of the lamellar structure that is not lost on repeated washing of the plastids. The oxidase activity was stable during prolonged storage of the particles at 4 C or -18 C. The Km (dihydroxyphenylalanine) for spinach leaf polyphenol oxidase was ...

Polyphenol oxidase is the popular enzyme involved in fruit-vegetable browning and melanin synthesis. In present paper, L-3-phenyllactic acid, a natural bacteriostatic substance, was investigated as an inhibitor of polyphenol oxidase. The results were demonstrated that residual activity decreased gradually with increase concentration acid. L ΔE values reaction system increased gradually. reversi...

polyphenol oxidase (ec. 1.10.3.1 ppo), an ionically unbound and thermostable enzyme, was extracted from the leaves of cinnamomum tamala having aroma flavor used to add in indian food and vegetables as a part of spices to enhance the taste of recipes. the enzyme was purified 2.63-fold with a total yield of 9.5% by ammonium sulfate precipitation followed by sephadex g-100 gel filtration chromatog...

Objective: Polyphenol oxidase or PPO (EC 1.14.18.1) is considered the enzyme responsible for quality deterioration and browning in different fruits during postharvest period. The objective of this study was to evaluate the antibrowning (inhibition of polyphenol oxidase activity) effect of Cysteine, Ascorbic acid, citric acid, kojic acid and glycine at two different pH (6 and 7) in  hawthorn. Me...

Clarified and standardized apple juice was ultraviolet-irradiated to inactivate polyphenol oxidase enzyme and microbiota, and its effect on bioactive compounds and stability during storage was also evaluated. Apple juice was irradiated with 345.6 J/cm² and treatment effect was evaluated in terms of color, antioxidant capacity, polyphenol content, pH, titratable acidity and total soluble solids....

Received: December 28, 2013; Revised; January 25, 2014; Accepted: March 2, 2014 . Abstract: A major problem in the micro propagation of litchi is the secretion of polyphenols into the medium by the tissues once excised. This secretion undergoes oxidation to produce substances that kill the tissues. The first visual symptom of deterioration is skin browning which has been reported to appear due ...