Abstract
As one step to prove why a color of bell pepper turns from green to red, we deal with identification of some lipids in green and red bell peppers. Total lipids were extracted with ether from bell pepper smashed in acetone. Solvent extracts were saponified. Identifications of fatty acids (ethyl esterified), tocopherols and sterols were performed by comparisons with gas-chromatographic retention time of standard compounds. Unsaturated ones (C18: 1, C18: 2 and C18: 3) in total fatty acids were 80.8% in the green and 66.2% in the red. While, C12: 0, C14: 0, C16: 0, C17: 0 and C18: 0 as saturated fatty acids were detected. In unsaponifiable matter, α-tocopherol, campesterol and β-sitosterol were detected in both bell peppers and α-tocopherol was especially contained in the red much more than the green.
Furthermore, concerning red bell pepper, acetone extract after removal of xanthophylls from total lipids by silica gel TLC were fractionated by celite 545-magnesium oxide column chromatography.
Major components in each fraction which was saponified and extracted with n-hexane were investigated by GC, MS, IR and 1H-NMR. As a result, isophorone, 6-hydroxy-4, 6-dimethyl-3-heptene-2-one, phytol and geranyl geraniol were identified from the red. These components were also detected in the green by GC, but an amount of geranyl geraniol was a trace.
