The exposition of stone fruits to pre-storage before cold storage promotes the stability of cellular tissues and reduces the activity of oxidative enzymes such as polyphenoloxidase
(Neves, Campos, Prill, & Roberto, 2013).
Along with its neutral salts, L-ascorbic acid is one of the main antioxidants used in plant products to prevent browning and other oxidative reactions in two ways: (1) by acting directly on the enzyme, complexing the copper of the prosthetic group of the polyphenoloxidase
, causing its inhibition; and (2) by reducing the quinones to their previous form of phenols, preventing the formation of dark pigments (SAPERS; MILLER, 1998).
in Beta vulgaris, Plant Physiol 1989; 24(1): 1-15.
The enzymatic browning reaction occurs due to presence of the polyphenoloxidase
enzyme (PPO) that catalyzes the oxidation reaction of phenolic compounds (Eissa, Fadel, Ibrahim, Hassan, & Elrashid 2006; Oliveira, Soares, Paula, & Viana 2008).
The surface color, pH, activity of phenylalanine ammonia-lyase, peroxidase and polyphenoloxidase
enzymes, chlorophyll and carotenoids contents were evaluated.
in Beta vulgarisb," Plant Physiology, vol.
It has been suggested that inactivating the enzymes responsible for browning (polyphenoloxidase
, lipoxygenase, and peroxidase), during blanching improves both colour and flavour of vegetables .
Arnon, "Copper enzymes isolated chloroplasts, polyphenoloxidase
in Beta vulgaris," Plant Physiology, vol.
Gu Y, Wang P, Kong CH (2009) Urease, invertase, dehydrogenase and polyphenoloxidase
activities in paddy soil influenced by allelopathic rice variety.
Mishra, "Catalase, peroxidase, and polyphenoloxidase
activities during rice leaf senescence," Plant Physiology, vol.
Increasing concentrations of lead, significantly (P < 0.05) decreased peroxidase enzyme activity (Figure 9), whereas polyphenoloxidase
enzyme activity under different lead treatments were increased, but this different were not significant (Figure 10).
da Mota, "Effect of pH and temperature on peroxidase and polyphenoloxidase
activities of litchi pericarp," Scientia Agricola, vol.