A Process for the Preparation of Leaf Protein Concentrates Based on the Treatment of Leaf Juices with Polar Solvents

Abstract

A new process is described by which a comparatively high yield of leaf protein concentrate may be obtained from alfalfa, white clover or pea vines. The leaves were first comminuted and the juice pressed from the pulp; the nitrogenous compounds were then precipitated with a measured volume of polar solvent (acetone or ethanol) added to the juice and finally the precipitate was washed with the solvent. A tasteless, odorless and creamy colored fine powder was obtained after air drying. The effect of some of the process variables on the yield of concentrate were examined, Losses of water from the leaves in the field decreased the yield of concentrate sharply. Allowing leaf juice to stand at room temperatures favored enzymatic proteolysis. Recovery of protein concentrate increased as the proportion of polar solvent to plant juice increased up to a ratio of 4 to 1, reaching a plateau at this level. Yields of concentrates obtained from alfalfa and white clover leaves were of the order of 32 and 15 g/kg respectively.