Nutritional assessment and antioxidant analysis of 22 date palm (Phoenix dactylifera) varieties growing in Sultanate of Oman

Objective: To assess the nutritional values and antioxidant analysis of 22 varieties of date palm (Phoenix dactylifera) fruit collected from various regions of the Sultanate of Oman. Methods: Nutritional parameters including moisture, fats, fiber, proteins, carbohydrates, and energy value were determined using standard methods of Association of Official Analytical Chemists. The antioxidant activity was screened for their free radical scavenging properties using ascorbic acid as a standard antioxidant. Free radical scavenging activity was evaluated using 1,1-diphenyl-2-picrylhydrazyl free radical. Results: The results of the date fruits (dried/tamar stage) revealed significantly higher moisture (15%-21%), dry matter (78%-86%), ash content (1.0%-2.0%), fiber (1.0%-2.5%), fat (0.1%-0.7%), protein (1.8%-3.8%), nitrogen (0.25%-0.55%), carbohydrates (74.5%-82.4%), and energy values (307-345.5 kcal/100 g). The antioxidant activity ranged between 40% and 86% depending upon the type of date and location. Overall, Khalas, Fardh and Khasab have significantly higher nutritional attributes; however, other varieties such as Barshi, Qush LuLu, Handal, and Khunaizi also have comparable nutritional values. The cluster analysis further evidenced the correlation of proximate parameters in different locations. Moreover, the nutritional and antioxidant attributes of similar date varieties collected from different locations were slightly varied. Conclusions: The present finding helps in understanding the nutritional significance of different date varieties in Oman while the lesser known varieties can be improved through sustainable horticultural practices as a valuable product. The study further reveals that the consumption of these dates' fruits would exert several beneficial effects by virtue of their antioxidant activity.