Abstract
Activities of ascorbate oxidase (EC 1.10.3.3, AAO) of 22 fresh vegetables including leafy, stalk, root and fruit vegetables were assayed. AAO activity was the highest in cucumber and pumpkin fruits (39-50 unit/g) followed by carrot roots, young ginger tubers and seedlings or sprouts (more than 1.5unit/g). There was no correlation between AAO activity and vitamin C content of fresh vegetables. Optimum pHs of AAO of fresh vegetables ranged from 5.15 to 6.50. AAO activity of all vegetables assayed was inhibited by citrate and the degree of the inhibition varied among vegetables. AAO are specifically localized in the part of fresh vegetables, and not uniformly distributed. The activities of basal part of carrot roots, celery stalks and middle part of cucumber fruits were higher than those of other parts. Although AAO activites of carrot roots and cucumber fruits decreased, those of radish seedlings and celery stalks increased during storage in arefrigerator (4°C).
