Flavor and antioxidant capacity of peanut paste and peanut butter supplemented with peanut skins

Peanut skins (PS) are a good source of phenolic compounds. This study evaluated antioxidant properties and flavor of peanut paste and peanut butter enhanced with peanut skins. PS were added to both materials in concentrations of 0.0%, 0.5%, 1.0%, 5.0%, 10.0%, 15.0%, and 20.0% (w/w). PS, peanut paste, and peanut butter used in the study had initial total phenolics contents of 158, 12.9, and 14.1 mg GAE/g, respectively. Hydrophilic oxygen radical absorbance capacity (H-ORAC) of peanut skins was 189453 μMol Trolox/100 g and addition of 5% PS increased H-ORAC of peanut paste and peanut butter by 52% to 63%. Descriptive sensory analysis indicated that the addition of 1% PS did not change intensity of descriptors in the sensory profile of either peanut paste or peanut butter. Addition of 5% PS resulted in significant differences in woody, hulls, skins; bitter; and astringent descriptors and 10% PS addition resulted in significant differences in most attributes toward more negative flavor.

Peanut skins are a low-value residue material from peanut processing which contain naturally occurring phenolic compounds. The use of this material to improve antioxidant capacity and shelf-life of foods can add value to the material and improve the nutritional value of foods. The improved nutritional qualities and unchanged flavor profile occurring with low levels of peanuts skins in peanut paste and peanut butter suggest potential application of this technology in various food industries.