Solvent cooking of cottonseed meats for extraction

Data have been presented for a solvent-cooking method of preparing cottonseed meats for extraction. The study includes experiments in which the flake moisture contents were increased to as high as 40% during the initial solvent cooking phase and decreased to about 10% by the end of the cooking cycle, and in which hexane and heptane were used as the cooking solvent in the presence of chemicals such as NaOH, NaCl, CaCl₂, and NH₃. Results showed specific trends with varying condiditions. Examples are: increase in the initial moisture content during cooking increases granulation and consequently the mass velocity; increase to 30% moisture content is sufficient to result in mass velocities above the desirable 2,000 lbs. per square foot per hour; free gossypol content of the extracted meals is lower with the higher initial cooking moisture contents and with the addition of certain chemicals (NaOH-CaCl₂) ; and the addition of the combination of NaOH and NaCl resulted in better overall filtration-extraction characteristics than either the NaOH-CaCl₂ or the NH₃-NaCl combinations. On the basis of the above results the following general conclusions can be made:

1. Solvent cooking offers the possibility of combining cooking, crisping, and slurrying (extraction) steps into a single operation in a process, such as filtration extraction for the direct solvent extraction of cottonseed.
2. Chemicals can be introduced as needed to promote free gossypol reduction and possibly maintain a high alkali protein solubility in the solvent extracted meal.
3. Agglomeration and extractability of the solvent-cooked cottonseed meats can be controlled.