REMOVAL OF HEAVY METAL CONTAMINATION FROM PEANUT SKIN EXTRACTS BY WASTE BIOMASS ADSORPTION

Peanut 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.