POLYPHENOL OXIDASE FROM GLIOCLADIUM VIRENS
 
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Pol. J. Food Nutr. Sci. 2001;51(1):25–30
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ABSTRACT
Polyphenol oxidase (PPO) was obtained after 48-h cultivation of G. virens in modified Czapek-Dox liquid medium with 2% starch as carbon source. The optimum pH and temperature of PPO was 6.0 and 35oC, respectively. At 30oC, the enzyme activity remained unchanged for 6 h, whereas at 350C and 40oC it lost half of the activity after 3.5 h and 20 min, respectively. The molecular weight of PPO, determined on a basis of native electrophoresis, was 50 kDa. The enzyme showed the greatest affinity towards syringaldazine, also oxidising chlorogenic acid, gallic acid, (-)epicatechin, (+)catechin, catechol, and phloridzin. PPO from G. virens oxidised the phenolic compounds present in apple juice and ascorbic acid was strong inhibitor of this reaction. The anti-oxidant properties of apple juice were shown to decrease to a small degree and only temporarily due to the oxidation by PPO from G. virens.
ISSN:1230-0322