Removal of Heavy Metal Contamination from Peanut Skin Extracts by Waste Biomass Adsorption

Abstract

AbstractPeanut skins are a processing waste product with potential as a low‐cost source of polyphenols for nutraceutical or functional food ingredient use. Aqueous extractions of peanut skins and subsequent concentration of these extracts can result in normally innocuous levels of heavy metals present to be increased to concentrations of human health concern. Adsorption utilizing waste biomasses is a promising method of removing these contaminants from extracts. Peanut hulls and chitosan cross‐linked beads were evaluated as possible adsorbents. The Langmuir adsorption model determined that peanut hulls were the more effective material. Peanut hulls removed 88.6 ± 1.9% of the cadmium present. 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 that this strategy is effective for heavy metal remediation of peanut skin extracts, making them a viable source of antioxidants in food applications.Practical ApplicationsPolyphenols are a rapidly increasing portion of the nutraceutical and functional food marketplace. Peanut skins are a waste product from the peanut blanching and roasting industry 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. The present study developed peanut hulls as a possible adsorbent material for the remediation of peanut skin extracts. The results of this study will be useful to peanut growers and shellers to develop new ingredient applications for peanut skin polyphenol extracts.