Apart from heat and moisture, there is yet another very important factor, which contributes towards a high percentage of oil being left in the cake and that is fibrous material.

Seeds or meals, deficient in fiber, prove very soft and smooth for pressing cage. They offer very little resistance and readily slip through the cage. Thus it may not be possible to exert sufficient pressure up on them as to secure the best yield of oil. Such meals have a tendency to readily escape through the drainage spaces between the lining bars of the cage and the pressure as soon as it is exerted is lost. On account of the meal being soft and smooth, the pressing worms are unable to get a proper grip upon such materials, and the meal is often worked up to a paste which will not move along the cage and no oil can be obtained from them. It is necessary that the materials which are to be pressed, in the expeller should contain a proportion of fibrous matter or ‘binder’ which will bind the material together to enable it to be pressed.

The skin of such seed as linseed, rape sesame undecorticated cotton seed etc. from a good binder. But when such seeds like cotton seeds are decorticated and the meats are very cleanly separated from the husk, those meals become too soft to set up any resistance in the expeller and the best yield of oil are difficult to be secured. When processing of such decorticated cotton seeds it is deidedly advan-tageous to allow a portion of the husk to go with the meals to the expeller. From 5-8% of husk with meats will have negligible effects on the quality of the oil or cake, but the expression of the oil will greatly improve, since the presence of the husk impart to the meal good binding properties.