Removal of Raw Peanut Flavor and Odor in Peanut Flour Processed by Direct Solvent Extraction¹

Peanut slices can be directly extracted with hexane yielding more soluble protein and better color than pre-press solvent extraction; however, flavor and odor are characterized as raw and “green beany”. The utilization of secondary extraction with hexane: ethanol azeotrope, hexane: methanol azeotrope and absolute ethanol subsequent to hexane extraction significantly improved flavor and odor characteristics of peanut flour. Hexane: propanol azeotrope did not significantly improve sensory evaluations. Hexane: ethanol azeotrope did not reduce soluble protein, yielding an NSI value of 95%. Hexane: methanol azeotrope and absolute ethanol slightly reduced NSI to 88% and 92% respectively. Color of peanut flour was not affected by secondary solvent extraction. Direct extraction of peanut slices with hexane, followed by hexane: ethanol azeotrope extraction, resulted in flour with good flavor and odor characteristics and with lighter color and more soluble protein than peanut flour produced by commercial pre-press solvent extraction.