Chemical examination of watermelon seed / by Frederick H. Power and Arthur H. Salway.

  • Power, Frederick B. (Frederick Belding), 1853-1927.
Date:
[1910?]
Catalogue details

Licence: In copyright

Credit: Chemical examination of watermelon seed / by Frederick H. Power and Arthur H. Salway. Source: Wellcome Collection.

    5/20 (page 361)
    A portion of the entire seed, when ground and extracted in a Soxhlet apparatus with light petroleum (b. p. 30-45°), yielded 19.0 per cent, of fatty oil. I. Examination of the Expressed Oil. The expressed oil of watermelon seed has a light yellow color and, unlike that from pumpkin seed, is completely devoid of fluorescence. The constants of the oil were determined with the following results: Oil extracted Expressed oil. by petroleum. Specific gravity 20°/2°°. 0.9233 Acid value. 3.9 Saponification value. 191.8 Iodine value. 121.1 0.9219 3-6 189.9 121.8 For a complete chemical examination of the oil, 250 grams of it were employed. It was first subjected to distillation with steam, but the dis¬ tillate contained no volatile oil nor any acid. Hydrolysis of the Oil. The oil which had been subjected to distillation with steam, as above described, was separated from the water, the latter then extracted with ether to recover a small amount of suspended oil, and, after adding this to the main portion, the whole was hydrolyzed by heating with an alco¬ holic solution of 70 grams of potassium hydroxide. The greater por¬ tion of the alcohol was then removed, water added, and the alkaline liquid repeatedly extracted with ether. The ethereal liquids were uni¬ ted, washed with a little water, dried with anhydrous sodium sulphate, and the ether removed, when about 0.5 gram of a light yellow oil was obtained, which soon solidified. The solid product, after three crys¬ tallizations from a mixture of ethyl acetate and alcohol, separated in pearly leaflets, melting at 163-164°. After drying at 1050 it was analyzed: 0.0881 gave 0.2667 C02 and 0.0905 H20. C = 82.6; H = 11.4. C20H84O requires C = 82.8; H = n .7 per cent. This substance, when dissolved in chloroform with a little acetic an¬ hydride, and a drop of sulphuric acid subsequently added, gave a blue coloration, rapidly changing to green, and finally to brown. It is evi¬ dently a phytosterol. The Fatty Acids. The alkaline, aqueous solution of potassium salts, which had been ex¬ tracted with ether as above described, was acidified with sulphuric acid and the mixture distilled with steam. The distillate, however, contained no volatile acid. The fatty acids remaining in the distillation flask were taken up with ether, the ethereal solution being washed, dried, and the solvent removed. For the purpose of determining the constants of the