Combination of separation and spectroscopic analytical techniques: application to compositional analysis of a minor citrus species

Abstract

The composition of juice and essential oil of Citrus limetta Risso was investigated. Multidimensional and enantio-gas chromatography were used for the elucidation of the volatile profile and the assessment of enantiomeric distribution. Predominant compounds were linalyl acetate (13.06 g/100 g), β-pinene (6.79 g/100 g), myrcene (1.40 g/100 g) and sabinene (1.05 g/100 g). Through a β-cyclodextrin column eight chiral pairs were separated, equally distributed between laevorotatory and dextrorotatory enantiomers. Liquid chromatography with triple quadrupole ESI-MS and PDA detection showed the presence of flavonoids and phenolic compounds (791.34 ± 36.83 and 32.97 ± 1.92 mg L⁻¹, respectively) in the juice. Sugars (i.e. glucose 202.23 ± 26.81 and fructose 146.73 ± 3.17 mM, respectively), aminoacids (i.e. proline 29.40 ± 3.78 and GABA 8.90 ± 0.95 mM) and organic acids (i.e. citrate 4.68 ± 0.81 mM) were determined in juice by means of ¹H NMR spectroscopy.

Keywords:

• Citrus limetta Risso
• enantiomer
• juice
• NMR
• polyphenols
• heartcutting

Acknowledgements

Authors wish to thank Dr Lucy Iacono for providing fruits of C. limetta from Aeolian Islands.