The effect of processing conditions on the properties of screw-press cottonseed meal and oil

Summary Processing conditions, particularly cooking procedures, have a marked influence on the chemical properties of screw-pressed meal and oil. Cooking prepared meats at 240–250°F., as in normal mill practice, produced meals with low free gossypol content but at the expense of considerable protein damage. The resultant crude oils showed some color reversion upon storage at 95°F. Dry cooking (7% moisture) at temperatures not exceeding 200°F. gave meals of improved chemical properties, but the crude oils exhibited considerable color reversion on storage. Wet low-temperature cooking (200–210°F.), followed by evaporative cooling, yielded a meal intermediate in quality between that for normal mill practice and dry low-temperature cooking. The crude oils, which corresponded to hydraulic-pressed oil, did not exhibit any appreciable color reversion upon storage at elevated temperatures. The selection of processing conditions, notably cooking, enables wide variations in the distribution of gossypol between meal and oil. The increase in the bleach color of crude oils stored at 95–100°F. was found to be directly related to the initial gossypol content of the crude oils. Presented at 44th Annual Meeting of the American Oil Chemists’ Society, New Orleans, La., May 4–6, 1953. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Service, U. S. Department of Agriculture.