Effect of processing on nutritional content of Peanut (Arachis hypogaea) skin waste as functional food and feed

Abstract

This study assessed the nutritional content of peanut skin (PS) (Arachis hypogaea) using different processing methods. Roasted Peanut Skin (RoPS) were collected from peanut vendors, Boiled Peanut Skin (BPS) obtained by cooking peanut to boiling temperature 100˚C and PS hand peeled, while Raw Peanut Skin (RaPS) were obtained by air drying and skin hand peeled. Samples were milled to finesse and analysed for proximate, anti-nutritional factors (ANF), mineral content, amino acid and fatty acid profile of PS according to standard methods. The result showed that BPS had high protein (21.85%). Application of heat on RoPS significantly increased ash content (20.44%) and BPS reduced significantly ether (1.60%) and crude fibre content (1.39%). Variations in mineral content was noticed in the samples with significant difference. The ANF were present in appreciable quantities while boiling reduced the ANF significantly in PS except in alkaloids. The amino acid profile level was enhanced by boiling PS while roasting reduced some of the amino acid content. The fatty acid profile indicated that RoPS had a high percent of fatty acids and lowered by boiling in BPS sample. This study noted that PS possess valuable nutritional qualities. The boiling process could be an effective method to reduce the levels of ANF and increase the protein content while roasting is adopted for improvement of the fatty acid content.