Date palm sap (Phoenix dactylifera L.), also known as "legmi", is a fresh juice extracted from date palm trees. The present study aimed to elucidate the effects of collection time (at the beginning of the tapping period and after seven days of collection) on the amino acid profile and physico-chemical properties of date palm sap from both male and female trees.Dry matter, protein, amino acid, and sugar profiles were determined using the Kjeldahl method, High-Performance Liquid Chromatography (HPLC), and High-Performance Anion-Exchange Chromatography with Pulsed Amperometric Detection (HPAEC-PAD), respectively. Date palm sap from both male and female trees contained high levels of carbohydrates. HPLC analysis showed that this fraction was dominated by sucrose in the sap sample from female trees compared to that from male trees. Male date palm sap was noted to exhibit lower dry matter content than female date palm sap but higher protein, total polyphenol, ash, and amino acid contents. While the major essential amino acids in the sap from male trees consisted of valine and threonine, they were represented by lysine and phenylalanine in sap samples from female trees. Further, Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE) analysis showed the presence of a proteinic band of 30 kDa only for the sap from male trees. Taken together, the sap from both male and female date palm trees had a number of properties that are highly valued by the functional food industry.

This work aimed to study the influence of date palm sex on the surface properties of date palm sap (DPS) (Phoenix dactylifera L.) during the collection period. The behavior at the interface and foaming properties were evaluated via equilibrium surface tension (drop volume) and bubbling method, respectively. Unlike male sap, the female sap was unable to produce foam due to its low rate of adsorption, low average hydrophobicity values, and low bulk viscosity values throughout the collection period. For male sap, there are significant differences (p<0.05) on foaming properties throughout the collection period. In fact, the last 3 weeks of sap collection were characterized by a decrease pace of surface tension which explains the enhancement of both foam capacity and stability. The last week of collection period present the best foam power (0.9). To explain these differences, the interactions of several factors and their affects on foaming properties were examined. Results showed a positive correlation between foam capacity and average hydrophobicity values. In the other hand, foam stability exhibits a positive correlation with the increase of protein concentration and bulk viscosity.

This work aimed to evaluate the nutritional quality of a typical natural drink from male and female Deglet Nour (DN) date palm (Phoenix dactyliferaL.) during the collection period. Dry matter, protein, amino acids, and sugar profiles were determined using AFNOR norm, Kjeldahl method, HPLC, and HPAEC-PAD, respectively. The male sap dry matter content was higher than that of the female. It decreased significantly through the tapping period. During the harvest, the male sap protein content decreased but increased significantly in the female sap. Finally, sugar fraction, for both male and female DN sap, was dominated by sucrose, glucose, fructose, and a small amount of myo-inositol. During the collection time, sugar content is affected by the sex especially for myo-inositol content that increased significantly in the female date sap, unlike that of the male one. This may be related to the fact that the male palm is more resistant to physiological stress, inducing myo-inositol formation during tapping.