Effect of Four Pollinating Sources on Nutritional Properties of Medjool Date (Phoenix dactylifera L.) Seeds

The objective of this study was to evaluate the effect of pollen source on the nutritional composition of seeds of the ‘Medjool’ date (Phoenix dactylifera L.) under conditions of northwest Mexico. The content of nutrients (protein, lipids, fiber, and ash), sugars (total, reducing, and non-reducing), and most abundant minerals, were evaluated, as well as antioxidant activities. The pollen of four cultivars (‘Deglet Noor’, ‘Khadrawy’, ‘Medjool’, and ‘Zahidi’) was selected. Four groups of three bunches were pollinated in each of the female palms. For the four treatments, the following ranges were obtained: Seeds had a weight of 1.32–1.41 g and low concentrations of protein (4.44–5.49 g/100 g) and lipids (9.62–10.19 g/100 g). The content of dietary fiber and ash was 59.65–72.59 g/100 g and 1.09–1.42 g/100 g, respectively. Total sugars content was 4.50–6.96 g/100 g, while the insoluble solids were 92.21–96.03 g/100 g. The predominant mineral was potassium with 399.97–459.79 mg/100 g dry weight, followed by sulfur with 135.51–162.67 mg/100 g dry weight. Finally, for antioxidant activities, DPPH (2,2′-diphenyl-1-picrylhydrazyl) and ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) assay results were 0.0014–0.0094 IC50 g/L and 0.176–0.299 IC50 g/L, respectively. The pollen sources had an effect on the physicochemical properties of the seeds of the ‘Medjool’ cultivar date. However, some of the parameters (diameter, total acidity, pH) did not show statistically significant differences. The pollen sources from the ‘Khadrawy’ and ‘Medjool’ cultivars were the ones that induced differences in physical, proximate, and nutritional parameters, while pollen from the ‘Zahidi’ source induced the largest differences for minerals. The results suggest that selection of the source of pollen has a significant effect on the nutritional properties of the date seed from the cultivar ‘Medjool’, and that its use could be feasible as a functional food or by-product of the date production.