Effect of drying methods and variety on the chemical composition, functional, and microbial properties of date flour

Background

Dates are highly perishable fruits, and maintaining their quality during storage is essential for both commercial viability and consumer satisfaction. One effective strategy for preserving their nutritional and functional properties is through drying, which reduces moisture content and inhibits microbial growth while concentrating essential nutrients. This study compared the impact of three drying methods (sun drying, hot air oven drying, and cabinet drying) on the chemical, functional, and microbial properties of date flour. The flesh of two date varieties, Amber and Sukkari, was processed by washing, drying at 65°C, milling, and sieving to obtain fine flour, which was then subjected to analysis.

Results

The results revealed that fat (5.35 ± 0.07%), protein (10.50 ± 0.00%), and crude fiber (8.57 ± 0.59%) contents were higher in hot-air oven-dried amber date fruit. Moisture (12.94 ± 0.63%), ash (2.37 ± 0.03%), and vitamin C (0.024 ± 0.00 mg/100 g) contents were reported to be higher in sun-dried Sukkari date due to the slower drying process and exposure to lower drying temperatures during sun drying, which allows for minimal thermal degradation of heat-sensitive compounds like vitamin C. Oven-dried Amber date powder displayed greater water absorption (1.10 mL/g) and solubility (66.60%). In terms of microbial analysis, both hot air oven-dried Amber and Sukkari dates had the lowest total viable count (1.19 × 10⁵ and 9.45 × 10⁴ CFU/mL, respectively).

Conclusion

Hot air oven drying is a suitable method for drying date fruit as it results in the highest retention of protein, fiber, and ash content while also maintaining low moisture levels, reducing microbial growth, and improving shelf life.