Apples ( Malus × sylvestris var. domestica ) are an important source of polyphenols (phenolic compounds) in the human diet ( Hertog et al., 1992 ) and a classic example of fruit susceptibility to enzymatic browning, which is a major problem for
Polyphenol oxidase (PPO) is a Type 3 copper protein, which catalyzes the oxidation of monophenols or o -diphenols to o -quinones ( Klabunde et al., 1998 ). PPO-generated quinones are highly reactive and will crosslink with proteins or polymerize
of plants are carotene (golden), pheophytin (olive green), chlorophyll a (blue–green), chlorophyll b (yellow–green), lutein (yellow), xanthophylls (yellow), betalains (yellow, orange, red, purple), and anthocyanins (red). In addition, polyphenols such
; Roberts, 1990 ). Bush tea contains 5-hydroxy-6,7,8,3′,4′,5′-hexamethoxy-flavan-3-ol ( Mashimbye et al., 2006 ), 3-0-demethyldigicitrin, 5,6,7,8,3′,4′-hexamethoxyflavone and quercetin, polyphenols ( Mudau et al., 2007a ), tannins ( Mudau et al., 2007b
., 2017 ). Therefore, it is important to develop strategies, perhaps through harvest and storage management practices, that maximize the concentration of endogenous tannins in the fruit. Polyphenols are a class of secondary plant metabolites derived
Agriculture ( Zepeda et al., 2014 ). Fruit and vegetables provide essential vitamins, minerals, fibers (soluble and insoluble forms) as well as bioactive compounds collectively known as phytochemicals. These include polyphenols, carotenoids, and sulfur
antioxidants present in tomatoes, whereas hydrophilic antioxidants include vitamin C and polyphenols ( Viuda-Martos et al., 2014 ). Polyphenols are powerful antioxidants that have been reported to interfere with the initiation, promotion, and progression of
). Presence of the P14a and JrPPO-1 genes in both ‘Serr’ and ‘Chandler’ was demonstrated using standard PCR to amplify 0.5-kb fragments from genomic DNA ( Fig. 2 ). Fig. 1. Polyphenol oxidase (PPO) enzymatic activity in leaves of walnut cultivars Serr and
, 1999 ; Mulas et al., 1998 ), several myrtle cultivars have been selected ( Mulas et al., 2002a ; 2002b ). Other studies on spontaneous myrtle plants have focused on their polyphenol compounds ( Hinou et al., 1988 ) and essential oil yield and
, 1987 ), leaves from sun-exposed locations in midsummer may contain a larger amount of CGA to scavenge abundant ROS. However, because G. bicolor is a minor crop, there has been little research on this plant and no reports of changes in polyphenol