STUDY ON PHYSICO-CHEMICAL AND PHYSIOLOGICAL CHARACTERISTICS OF DATE PALM FRUITS (Phoenix dactylifera L.) CV. UM-ALDEHIN

This investigation was conducted on ‘um-aldehin’ date cultivar (Phoenix dactylifera L.) during the growing season of 2010 to study changes in physico-chemical and physiological characteristics during the different stages of fruit development. The results showed that the pattern of fruit growth and development on the basis of increase in the fresh weight of fruit, volume, length and diameter followed a single sigmoid growth curve. These specifications increased as the fruits developed and reached to the highest values at Khalal stage. Results also showed a decrease in values of moisture content, total titratable acidity, fatty compounds with an increase in total soluble solids, total and reducing sugars as fruits advanced toward the stages of Rutab and Tamer. Changes in respiration rate associated with ethylene production of fruits indicated to an increase in respiration rate when fruits entered the ripening stage (Rutab) while the highest increment of ethylene production occurred 7 days before the rapid increase in respiration rate. According to the results, there was a significant increase in the activities of invertase and cellulase enzymes at the end of Khalal stage and also at the beginning of Rutab stage.