Investigation on the changes in the amounts of some organic substances and polyphenol oxidase activity during development and ripening of Cherry laurel (Prunus laurocerasus L.) fruits

SUMMARY In this study, the changes of activity in polyphenol oxidase (PPO) during the development and ripening of cherry laurel fruits were investigated. Also, the changes of amounts in total carbohydrate, soluble protein, phenolic substances and ascorbic acid were determined. For this purpose, PPO activity and the other parameters in fruits which picked up every week from two cherry laurel cultivar were spectrophotometrically measured and, these analyses were begun after two months of pollination and continued until the fruits are mature. At the end of analyses, PPO activity gradually increased during the development of fruits, however,it decreased in the stage of ripening. Total carbohydrate and soluble protein level significantly increased, on the contrary, the level of vitamin C (ascorbic acid) decreased during the development and the ripening of the fruits. The changes in the phenolic substance content of fruits were determined as similar with changes in PPO activity. In addition, one to two PPO isoenzymes in fruits were determined by polyacrylamide gel electrophoresis. The investigation of features of polyphenol oxidase and the determination of the chemical content of cherry laurel fruits made originally contribution to the literature. It is expected that obtained results can be used for processing of the fruits and for increasing number of their cultivar forms. Key Words: Prunus laurocerasusy Polyphenol oxidase, Development and Ripening, Soluble Protein, Phenolic Substance, Vitamin C, Total Carbohydrate VI