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ARS Home » Southeast Area » Raleigh, North Carolina » Market Quality and Handling Research » Research » Publications at this Location » Publication #319557

Title: Removal of heavy metal contamination from peanut skin extracts by waste biomass adsorption

item MASSIE, BRIANNA - North Carolina State University
item SANDERS, TIMOTHY - Retired ARS Employee
item Dean, Lisa

Submitted to: Journal of Food Process Engineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/4/2014
Publication Date: 1/3/2015
Publication URL: DOI:
Citation: Massie, B.J., Sanders, T.H., Dean, L.L. 2015. Removal of heavy metal contamination from peanut skin extracts by waste biomass adsorption. Journal of Food Process Engineering. 38:555-561.

Interpretive Summary: This publication describes food waste materials being applied to the production of a functional food products. Peanut skins are usually removed from peanuts before human consumption. They are considered processor waste. This material is very high in polyphenol compounds that may be beneficial to human health. After removal of these compounds from the skins by aqueous extraction, the solutions containing the polyphenols were spray dried to produce a functional food ingredient. This concentration resulted in increased levels of heavy metal contaminants which was undesired. It was found that by pretreating the solutions with ground peanut hulls, another peanut processing waste product, certain metals such as cadmium were removed. The solutions could then be spray dried to form a better antioxidant powder to use as a functional food ingredient.

Technical Abstract: Polyphenols are a rapidly increasing portion of the nutraceutical and functional food marketplace. Peanut skins are a waste product which have potential as a low-cost source of polyphenols. Extraction and concentration of peanut skin extracts can cause normally innocuous levels of the heavy metal content to be increased to concentrations of concern. Adsorption utilizing waste biomasses is a promising method of removing contaminants from extracts. Peanut hulls and chitosan cross-linked beads were chosen as possible adsorbents. The Langmuir adsorption model was used to determine that peanut hulls was the most effective material. Peanut hulls removed 88.6 ± 1.9 % of cadmium. Apparent removal of arsenic (21.7 ± 9.5%) showed no correlation to adsorbent dosage. Successful removal of cadmium without reduction of the phenolic content of the extracts showed this strategy is feasible for heavy metal remediation of peanut skin extracts making them a viable source of antioxidants in food applications.