Novel Applications of Walnut Husk Extracts

During the processing of nuts, a considerable amount of material such as husks and shells are produced and often discarded as compost or landfill. In producing walnuts for retail sale, the husks are often discarded. Walnut husks contain tannins and polyphenolic compounds and the husk may be used for treatment of intestinal parasites and fungal infections. Green walnut husks harvested from Missouri and Michigan were extracted in ethanol using ultrasonic assisted extraction and extracted using supercritical carbon dioxide with an ethanol modifier. Ultrasonic assisted extraction was performed at room temperature for an hour, while supercritical fluid extraction was performed at 60°C with an ethanol mole fraction of 15%. The effects of pretreatment drying of walnut husks upon antioxidant potential as measured by the total phenolic content (TPC) assay were evaluated. A variety of diverse applications were evaluated including antioxidant and corrosion inhibition of extracts blended in paints, oxygen scavenging of extracts infused in plastics, and antimicrobial effects.