Study of phenolic compound and antioxidant activity of date fruit as a function of ripening stages and drying process

Edible parts of two varieties of date palm (Mazfati and Kalute varieties) (Phoenix dactylifera) fruits (DPF) from Iran were analyzed to determine their phenolic compound and antioxidant activities (AA). Antioxidant activity evaluated using typical methods such as 2, 2-diphenyl-1-picrylhydrazyl (DPPH), reducing power and total antioxidant method. The total phenolic content (TPC) of the DPF was measured using Folin-Ciocalteau method. The samples used in this study included samples were gathered at three stages of khalaal, rutab, tamr and dried date from Bam and Jiroft date. The TPC ranged from 2.89 to 4.82, 1074 to 856.4 and 782.8 mg gallic acid equivalents (GAE/100 gdw sample) for khalal, rutab and tamr stage of Mozafati variety, respectively. This work demonstrates the potential of Iranian dates as good sources of antioxidant which can be used as functional food ingredients. The influence of sun drying process and oven drying at temperature ranged 50-80 degrees C on phenolic compounds and AA of date palm fruits were investigated. Result of drying process showed that TPC and AA varied with temperature and decreased by increase of drying temperature (from 667.3 to 610.5 mg galic acid in sun dried dates of Mozafati and Kaluteh respectively to 314.2 and 210.4 in dried dates (80 degrees C) of Mozafati and Kaluteh respectively).