Protein isolates from Egyptian sweet potato leaves

Abstract

The optimum conditions for protein extraction from sweet potato leaves were studied. The results obtained led to the following conclusions: pH 10 was found to be the best pH for maximum protein recovery after 4 h of extraction using distilled water in a ratio of 20: 1 (v/w) solvent to sweet potato leaf powder; to increase the yield of the extractable protein (leaf protein concentrate, LPC) it was necessary to double the extraction steps.After extraction, the protein was precipitated according to its isoelectric point which was found at pH 4.The LPC yielded from sweet potato leaves had less value of antinutritional factors than found initially in the leaves. Also, the functional properties of the isolated LPC were studied: Oil holding capacity of LPC was higher than water holding capacity of the same protein, also it was higher than oil holding capacity of the albumin. The coagulated protein value of the LPC was much lower than that of albumin. The foamingcapacity of LPC at pH 7 was higher than that found at pH 4 and both were much lower than those of albumin. On the other hand the foam of LPC was more stable at pH 7 than that found at pH 4.