and sealed with cotton wool. The thimble was inserted in a Soxhlet extraction flask and extracted with boiling hexane (boiling point 68 °C) for 10 h or until the solvent at the sample chamber was colourless,
indicating it was free from oil and that all the oil had been extracted. The defatted DPSP was removed from the extraction thimble and left to dry overnight, to allow the hexane to evaporate.
This defatted date seed powder (DDSP) was kept at −20 °C until processed further.
The residual fat content and protein content of the defatted powder were reported previously as 1.01% (w/w) and 6.13% (w/w), respectively.
This protein content is equivalent to a 100% yield of protein. The effect of the hexane extraction step on the functionality of the proteins was not determined. However, it is well known that the methods used to extract the proteins from the powder will also affect the functionality, so the additional effect of hexane extraction is likely to be negligible.