Analysis of Fruit Skin Chlorophyll and Its Derivatives as a Valid Index in Determination of Commercial Maturity of Pear (Pyrus communis L.)

Fruit maturity at harvest is one of the most effective factors determining the increase of storage time and quality of pear fruit. One of the suitable fruit maturity indices during commercial harvest date of pear fruit is the change of its ground color. In this research, changes of proto-chlorophyll and its derivatives including a, b and total chlorophylls in 9 cultivars of pears namely: Spadona, Bartlett, Beyrouti , Dargazi, Dutchess, Shahmiveh, Felestini, Coscia and Louise Bonne during four different times, two weeks before commercial fruit maturity, commercial fruit maturity time, one and two months after fruit storage were evaluated. Measurement of chlorophyll was performed using spectrophotometric method and the amount of single spectrum light absorption under wave lengths of 625, 647, 664 nanometer. The most content of chlorophyll a and b and total chlorophyll in commercial maturity stage and different stages of storage devoted to Spadona that have clear difference in comparison to the others, but Felestini cultivar shows the less extent of the above mentioned factors during different stages of the evaluation. Also, in all stages of the experiment, chlorophyll a was greater than chlorophyll b. In most cultivars, changes of chlorophyll showed clear downfall with low standard deviation during the four different times. Based on the results, it can be concluded that evaluation of skin chlorophyll and its changes are valid and usable indexes in determination of commercial maturity of fruit in understudy cultivars except Shahmiveh and Louise Bonne cultivars