Polyphenol oxidase of dates

Properties of polyphenol oxidase obtained fromMusa acuminata × balbisianaColla cv. “Pisang Awak” pulp and peel Propiedades de polifenoloxidasa obtenido de la pulpa y piel deMusa acuminata × balbisianaColla cv. “Pisang Awak”

“…Mayer and Harel (1979) also reported that K m values for PPO from bananas were relatively low (ranging from 0.01 to 0.02 mM), which indicates higher affinities of the banana PPO for substrates. However, the affinity of PPOs from several plant sources for different phenolic substrates were relatively low (K m values were within 0.5-10.0 mM), as reported by Fuji and Tono (1988); Hasegawa and Maier (1980); Mayer and Harel (1979); Oda et al, (1989); Waliszewski, Ma´rquez, and Pardio (2009) ;Zawistowski, Biliaderis, and Eskin (1991).…”

Diphenol Oxidases, Enzyme-catalysed Browning and Plant Disease Resistance

“…These cite differences in molecular weight, number of subunits, kinetic and electrophoretic properties and pH optima of catecholases from different sources. In addition the maturity of the source and plant organ or organelle, or artefacts formed during purification, may alter the results observed (Galeazzi et al, 1981;Gutteridge and Robb, 1975;Halim and Montgomery, 1978;Hasegawa and Maier, 1980;Janovitz-Klapp etal., 1989;Kellyet al, 1990;Lam and Ho, 1990;Leoni and Palmierri, 1990;Matheis and Belitz, 1977;Murao et al, 1993;Murata etal., 1992;Nakamura etal., 1983;Palmer, 1963;Park and Luh, 1985;Racusen, 1969;Sato, 1982;Walker, 1964aWalker, , 1964bWong et al, 1971;Yurkow and Laskin, 1989;Zawistowski etal., 1988a,b;Zhou et al, 1993). It is still not clear how reliably information obtained from one source of catecholase can be extrapolated to another.…”

Accelerated ripening of Dhakki dates by artificial means: ripening by acetic acid and sodium chloride

“…Currently, NaCl at 2% concentration has accelerated the ripening process efficiently and yielded an optimum quality product. The detection of invertase, polygalacturonase, cellulase, polyphenol oxidase and other ripening enzymes has been reported in dates at the Doka stage (Hasegawa & Maier, 1980;Hasegawa & Smolensky, 1971). It has further been reported that polygalacturonase and cellulase were absent or present at only a low level in the green date fruit but displayed large increases in activity during ripening (Hasegawa & Maier, 1980;Saleem et al, 2002).…”

“…The detection of invertase, polygalacturonase, cellulase, polyphenol oxidase and other ripening enzymes has been reported in dates at the Doka stage (Hasegawa & Maier, 1980;Hasegawa & Smolensky, 1971). It has further been reported that polygalacturonase and cellulase were absent or present at only a low level in the green date fruit but displayed large increases in activity during ripening (Hasegawa & Maier, 1980;Saleem et al, 2002). In the present study changes brought about by the activity of the ripening enzymes were reflected in a reduction in fruit firmness, color changes from yellow to reddish brown and taste development, and the treatments possibly activated such enzymes.…”