Investigation of Bound Aroma Constituents of Yellow-Fleshed Nectarines (Prunus persica L. Cv. Springbright). Changes in Bound Aroma Profile during Maturation

Abstract

Glycosidically bound volatile constituents of yellow-fleshed clingstone nectarines (cv. Springbright) were identified and quantified at three stages of maturity. Glycoconjugates were isolated by LC on a C₁₈ reversed phase column with methanol elution followed by hydrolysis with a commercial pectinase enzyme. Forty-five bound aglycons were identified for the first time in yellow-fleshed nectarine. Thirty were terpene derivatives, and the most abundant ones were (E)- and (Z)-furan linalool oxides, linalool, α-terpineol, (E)-pyran linalool oxide, 3,7-dimethylocta-1,5-diene-3,7-diol, linalool hydrate, 8-hydroxy-6,7-dihydrolinalool, (E)- and (Z)-8-hydroxylinalools, and (E)- and (Z)-8-hydroxygeraniols. The group of C₁₃ norisoprenoids included 3-hydroxy-β-damascone, 3-hydroxy-7,8-dihydro-β-ionone, 3-oxo-α-ionol, 3-hydroxy-7,8-dihydro-β-ionol, 3-hydroxy-β-ionone, 3-oxo-7,8-dihydro-α-ionol, 3-hydroxy-5,6-epoxy-β-ionone, 3-oxo-retro-α-ionol (isomers I and II), 3-hydroxy-7,8-dehydro-β-ionol, 4,5-dihydrovomifoliol, and vomifoliol. Generally, levels of bound compounds, in particular monoterpenols and C₁₃ norisoprenoids, increased significantly with maturation. δ-Decalactone was the only lactone found in the enzymatic hydrolysate of yellow-fleshed nectarine, but its level was much lower than that of its free form. Keywords: Nectarines; Prunus persica; flavor; aglycons; C₁₃ norisoprenoids; maturation