Compositional and Functional Characteristics of White Clover Leaf Protein Concentrates Prepared under Various Conditions

Abstract

White leaf protein concentrates (white LPC's) were precipitated by varying pH (2.0, 4.0 or 7.8) and temperature (4°C or 80°C) of the brown juice obtained as a supernatant at pH 5.0 expressed white clover (Trifolium repens) juice, and the precipitates were freeze-dried. Similar chemical compositions were found for all LPC's when the LPC's were washed with an acidic aqueous solu tion. However, the yield of white LPC and its functional properties were affected by the preparative procedures. The LPC prepared by acid precipitation without heating showed better functional properties than the other preparations. By this technique, however, at most 60% of the protein was recovered from the brown juice. Though the yield of white LPC was improved by heat coagulation followed by washing at pH 4.0, heat treatment produced more bulky, more water and oil absorbing, and less soluble white LPC than that obtained by acid precipitation. These observations suggest that heat treatment in preparing white LPC might promote the formation of intermolecular bonds which produce insoluble hard particles having larger void volume.