Regional Fruit Research Station, Punjab Agricultural University, Abohar-152116.
**Present address: Joint Director of Research, Punjab Agricultural University, Ludhiana.
***Present address: Jr. Plant Physiologist, Central Mango Research Station, Lucknow.
*Paper presented at the Third International Symposium on Sub-tropical and Tropical Horticulture, Bangalore (Feb. 1972).
The ripening process in dates cv. Hillawi (USA), Khadrawi, Medjool, Shamran, Deglet Noor and Barhee with respect to different physico-chemical characteristics was studied at different developmental stages, viz. pre-Doka, early-Doka, late-Doka, Early-Dang and late-Dang. Medjool was found to have greater pulp/stone ratio as compared to other cultivars. The dry matter percentage increased as the period advanced from pre-Doka to early-Dang stage. Unlike the reducing and non-reducing sugars, the total sugars displayed less variability at different stages of ripening. In Deglet Noor, non-reducing sugars content was the highest of all. There was a gradual increase in reducing, non-reducing and total sugars as the ripening period reached late-Doka stage and only a slight decrease was observed thereafter. However, a sharp rise in these sugars occurred as the fruit transformed from pre-Doka to early-Doka stage. The possible association of enzyme invertase and other environment factors with the ripening process is discussed.
