Submitted to: American Peanut Research and Education Society Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 5/20/2004
Publication Date: 7/13/2004
Citation: Mehrotra, M., Sanders, T.H., Hendrix, K. 2004. Color sorting to remove fruity fermented off-flavor in roasted peanuts. American Peanut Research and Education Society Proceedings. Vol. 36, p. 41.
Technical Abstract: Fruity fermented off-flavor results from high temperature exposure during curing of peanuts. Immature peanuts are associated with increased fruity fermented off-flavor and upon roasting, in any grade size, acquire a darker color and have lower flavor potential. This work was conducted to determine the effectiveness of a novel application of machine color sorting to remove fruity fermented off-flavor by removal of darker (immature) roasted peanuts. Fruity fermented and non-fruity fermented runner-type peanut lots (65 kg each) were roasted at 174 ± 2 C, blanched, and subdivided into 3 lots. Each sub-lot was color sorted using a Sortex color sorter (model #3201). The color sorter was adjusted to remove ca. 5, 12 and 20% of the darkest peanuts, which had resultant Hunter L colors of ca. 40, 42 and 44. The lighter color-sorted peanuts (mature) were stored at 30 C and samples were evaluated at 0, 1, 2, 4, 8, and 12 wk. Peroxide value (PV), oxidative stability index (OSI), descriptive sensory analysis, and single-seed roast color were determined for all samples. The darker (immature) peanuts had higher concentrations of unsaturated fatty acids, FFA and carbohydrates. Descriptive sensory analysis showed that fruity fermented off-flavor decreased with successively higher percentage removal of darker-roasted, immature peanuts. The reduction of fruity fermented off-flavor in roasted peanuts by machine color sorting may be of significant economic value to the peanut industry.