Summary The pigmentation of cooked cottonseed has been shown to depend principally upon the moisture content and period of heating of the seed. Several samples of crude hydraulic‐pressed and screw‐pressed oils produced under known processing conditions were found to differ markedly from each other with respect to their original colors and refining characteristics. The screw‐pressed crude oils were more deeply colored and contained one principal pigment, whereas the hydraulic‐pressed oils contained two principal pigments. The absence of significant amounts of gossypol in the crude oils has been demonstrated by means of a new technic for the quantitative isolation of gossypol. The crude oil pigments differed from gossypol, but like gossypol, they were removed during alkali refining. The pigmentation of the crude oils has been shown to depend principally upon the pigmentation of the original seed and the moisture content of the seed during cooking. On the basis of their absorption spectra it has been deduced that the alkali‐refined hydraulic‐pressed oils contain two to three pigments originally present in the crude oils whereas the alkali‐refined serewpressed oils contain these same pigments as well as a large number of decomposition products of the principal crude oil pigment.

No abstract

Summary Selected varieties of cottonseed comprising three Sea Island cottons, four Egyptian cottons, and 10 upland cottons providing two or more varieties having the following characteristics: short, intermediate, and long staple; low, intermediate, and high content of lipids; and low, intermediate, and high content of protein, were planted and grown under as nearly identical conditions as possible. The initial contents of moisture, lipids, nitrogen, gossypol, and gossypurpurin of the harvested seed were determined, after which samples of all of the seed were stored for a year under identical conditions and analyzed periodically for gossypol and gossypurpurin. A definite relation was found between the species of the seed and their content of gossypol and gossypurpurin. Sea Island and Egyptian seed of the speciesG. barbadense contained more gossypol and very much more gossypurpurin than seed of the speciesG. hirsutum. Within the speciesG. barbadense Sea Island seed contained more gossypol and less gossypurpurin than Egyptian seed. Gossypurpurin increased during storage of all of the seed whereas gossypol varied in a number of different ways, increasing in some, decreasing in others, and remaining relatively constant in a few samples of stored seed. A discussion is presented of the theoretical and practical implications of these observations.

Summary Gossypurpurin was prepared from gossypol via diaminogossypol, and its properties compared with gossypurpurin isolated from cottonseed pigment glands. A tentative molecular formula for synthetic gossypurpurin, C30H32O7N, has been proposed on the basis of its elementary composition. The native pigment could not be obtained in the same degree of purity as the synthetic product and the analytical data could therefore not be brought into exact agreement for the two products. However solutions of both pigments in chloroform exhibit almost identical absorption spectra and identical antimony trichloride tests. Qualitative reactions seem to indicate that the functional groups of both native and synthetic gossypurpurin are identical, and the ready conversion of both products to gossypol upon contact with acid seems to indicate that their basic structures are similar.

Summary Cottonseed pigment glands, produced from whole cottonseed meal and defatted cottonseed meal by the gland flotation process, have been investigated as a raw material for the production of gossypol. Methods based on the previously reported properties of gossypol and cottonseed pigment glands have been developed for the relatively rapid isolation of gossypol from pigment glands. Extraction of gossypol from pigment glands with acetone followed by precipitation of gossypol acetic acid from the extract was found to be the preferable method for obtaining pure gossypol in good yields. The precautions which must be applied in order to produce gossypol on a large scale by the acetone‐acetic acid method are discussed together with methods for the purification and preservation of gossypol.