| Abstract
| - In extracts obtained by liquid−liquid extraction from French cider(2S,4R)- and(2R,4R)-2-methyl-4-pentyl-1,3-dioxane, 1a and 1b as well as(2S,4R)- and(2R,4R)-2-methyl-4-(2‘(Z)-pentenyl)-1,3-dioxane, 2a and 2b, were identified by capillarygas chromatography (HRGC) and capillary gaschromatography−mass spectrometry (HRGC−MS). Absoluteconfiguration and conformation of the1,3-dioxanes was determined by nuclear magnetic resonance (NMR)spectrometry techniques [13C,1H, nuclear Overhauser enhancement (NOE), and H/Hhomonuclear decoupling], multidimensionalgas chromatography (MDGC), and by comparison with synthesized referencecompounds. Anonenzymatic formation of 1a and 1b and 2aand 2b during fermentation of apple juice wasproposedleading to 22, 8, 2, and <1 mg/L of 1a, 2a,1b, and 2b, respectively in cider. Keywords: Cider; enantiodifferentiation; 2-methyl-4-pentyl-1,3-dioxane;2-methyl-4-(2‘(Z)- pentenyl)-1,3-dioxane; conformation
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