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Title: Chemical optimization of protein extraction from sweet potato (Ipomoea batatas) peel

Author
item MALONEY, KATHERINE - North Carolina State University
item Truong, Van Den
item ALLEN, JONATHAN - North Carolina State University

Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/11/2012
Publication Date: 11/20/2012
Citation: Maloney, K.P., Truong, V.D., Allen, J.C. 2012. Chemical optimization of protein extraction from sweet potato (Ipomoea batatas) peel. Journal of Food Science. 77(11):E307-E312.

Interpretive Summary: Proteins isolated from sweetpotatoes have several biological activities that can be beneficial to human health. Caiapo, a protein extract from a white-skinned sweet potato cultivar in Japan, has been shown to lower fasting blood glucose levels and increase insulin sensitivity in type II diabetics. The objective of this research was to chemically optimize the process for extracting proteins from sweet potato peel, a waste generated during processing of sweet potato puree. Proteins were dissolved by mixing peel with optimal levels of saline solvent and then precipitated with calcium chloride. The results show that potentially valuable proteins can be extracted from sweet potato peel and industrial costs can be minimized by using these optimum conditions.

Technical Abstract: Proteins isolated from sweet potatoes (Ipomoea batatas) have been shown to possess antidiabetic, antioxidant, and antiproliferative properties. The objective of this study was to chemically optimize a process for extracting proteins from sweet potato peel. The extraction procedure involved mixing peel with saline solvent to dissolve proteins and then precipitating with calcium chloride. Quadratic and segmented models were used to determine the optimum sodium chloride concentration and peel to solvent ratio to maximize protein solubility while minimizing solvent usage. A segmented model was also used to optimize the concentration of calcium chloride used for precipitation. The highest yield was obtained by mixing blanched peelings with 59.7 mL of 0.025 mM sodium chloride per g peel and then precipitating with 6.8 mM calcium chloride. The results of this study show that potentially valuable proteins can be extracted from peel generated during processing of sweet potatoes and industrial costs can be minimized by using these optimum conditions.