Simple unit for extracting protein in bulk from leaves

Abstract only - no further text Most of the leaf protein (LP) used in human feeding trials was made from crops put successively through a chaff-cutter, a pulp and a belt-press. This elaborate process is simply a scaled-up version of the technique that is essential in agronomic work (Pirie, 1978). Now that the idea of using LP is gaining acceptance, there is an incentive to simplify the process of extraction. A simplified screw expeller, modified so as to rub the leaf adequately More pressure is applied, has already been described (Pirie, 1977). That unit expressed juice in one operation but would not work satisfactorily on material that had not been through a chaff-cutter. By intraducing an epicyclic gear, which ensures that the section of the expeller in which there is pressure always overtakes the section in which there is rubbing, and by introducing a mechanism that automatically stops the inflow of crop when there is an incipient overload, we have made a prototype one-piece extractor. This can conveniently be used to produce quantities of juice containing 1-10 kg LP from crops without chaff-cutting. The unit demonstrated is a little more elaborate than is necessary because it is designed to allow more adjustment than would be needed on a production model, it also allows power consumption to be measured. It would, nevertheless, be much cheaper than existing equipment: it is also more economical. It uses about 300 W when processing IOO kg (fresh weight) croph. Larger units, working on the same principle could be made. There is more fibre in juice made in any unit based on the principle of the screw-expeller than in the pulper plus belt-press combination. Part of this fibre will contaminate the LP, but probably not to a harmful extent. Pirie, N. W. (1977). ErpLAgric. 13, 113. Pirie, N. W. (1978). Leaf Rohn and Other Aspects of Fodder Fractionation. London: Cambridge University Rcas (In the Prcsa)