Morphology characterization and chemical composition of United Arab Emirates date seeds and their potential for energy production

Abstract

The seeds of a local date palm cultivar from the United Arab Emirates, Allig, were characterized in this study. Soxhlet, Folch, and CO2 supercritical extraction were employed to obtain oil from Allig date seed (DS) powder composed of 0.1–0.3 mm particles, yielding oil extraction yield percentages of 10.2%, 9.5%, and 9.8%, respectively. The main fatty acid in the extracted oil was saturated stearic acid, comprising 47.9% of the total fatty acid content. After oil extraction, the total metal content in the DSs dropped from 3.2% to 2.8%, suggesting that some metals were extracted with the oil. On the other hand, the average heating value of the DSs increased from 28.55 ± 1.84 to 29.63 ± 1.28 MJ/kg after oil extraction. The average percentages of dehydration moisture, devitalization protein and carbohydrates, devitalization lipids, and solid decomposition in the DSs before oil extraction were 1–2%, 50–55%, 10–15%, and 30–35%, respectively, whereas those for the DSs after oil extraction were 20–25%, 35–30%, 0%, and 35–40%, respectively. As expected, the lipid content dropped after oil extraction. The heat of combustion and extracted oil results indicate that palm DSs, with their relatively high energy densities, have potential as a source of energy, among other notable organic products.