Description

Abstract: Peanutskin was removed by direct peeling, blanching, and roasting. Total phenolics (TPs), total antioxidantactivity (TAA) and free radical scavenging capacity of peanutskin extracts were determined. The composition of ethanolic extracts of peanutskin obtained from each processing method was determined by LC-MS and HPLC. Peanutskinprocessing methods significantly affected total extractable phenolics and their composition. Roasting had limited effects on concentration of TPs while blanching caused 89% loss of TPs. TPs in directly peeled, roasted, and blanched peanutskins were 130, 124, and 14.4 mg/g dry skin, respectively. Catechins, A-type and B-type procyanidin dimers, trimers and tetramers in chemically purified peanutskin extracts were identified by LC-MS. Total catechins, procyanidin dimers, trimers and tetramers in directly peeled peanutskin were 16.1, 111.3, 221.3 and 296.1 mg/100 g, respectively, versus 8.8, 143.5, 157.5 and 203.9 mg/100 g, respectively, in roasted dry skin. TAAs and free radical scavenging capacities of peanutskin extracts were all higher than those of Trolox and Vitamin C at equivalent concentration. Peanutskin, a by-product of the peanutprocessing industry, was found to contain potent antioxidants and could provide an inexpensive source of antioxidants for use as functional ingredients in foods or dietary supplements.