The Study of Changes in Phytochemical Compounds of Date Fruit cv. Barhee During Development and Ripening

Studying phytochemical changes of fruits is very important for plant physiologists and pomologists. Date is an important horticultural fruit in Iran mainly produced in southern regions. Barhee is considered one of the most important date palm cultivars. The fruit of cv. Barhee can be harvested and consumed at different maturation stages including Khalal, Rutab and Tamar. In the present study, the biochemical alterations of date fruit cv. Barhee during development and ripening stages were studied.

The experiment was carried out in a randomized complete block design with three replications. Sampling was done at Date Palm Research Institute Collection Orchard located in Ahvaz. First, fruits were harvested in five different developmental stages including late Kimri, Khalal, mainly Khalal, mainly Rutab, fully Rutab and Tamar. The fruits were then transferred to Quality Analysis Lab of Department of Horticultural Science at Shahid Chamran University of Ahvaz. Selected uniform fruits were used for the analysis of different phytochemical compounds. Chlorophyll, carotenoid, starch, soluble sugars, phenolic compounds, flavonoids and antioxidant capacity were analysed using spectrophotometric methods. The type and concentration of sugars, organic acids, and phenolics were assessed using HPLC. Also, vitamin C content was determined by titration againt DCIP dye.

The results showed that soluble sugars increased significantly during ripening stages, and glucose and fructose were the main detected sugars for Barhee cultivar. The amount of sucrose was negligible. The acidity of the fruit increased at initial growth stages and then decreased gradually till Rutab stage. At the end of ripening process and at Tamar stage, the amount of organic acid content increased to 2.45 mg/g FW. Among the detected organic acids, acetic acid was dominant in Tamar stage, while in the earlier stages malic acid was considered the main organic acid. Other major investigated compounds, including flavonoids, chlorophylls, carotenoids, starch and vitamin C decreased during the development. Different compounds including p-cinamic, gintistic, gallic, chlorogenic, vanilic, caffeic, syringic and p-cumaric acids were detected by HPLC evaluation of phenolic acids. Among them, gallic acid was the dominant, and the trend was incremental during the development of fruit.

Comparing the current results with published data for other date cultivars shows that there are considerable differences in biochemical compounds among different cultivars. In this cultivar, the increasing trend of accumulation of soluble sugars, organic acids, phenolic compounds and antioxidant capacity during ripening stages from late Kimri to Rutab and Tamar stage makes the fruit an important source of essential nutrients.