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On-line gas chromatography combustion/pyrolysis isotope ratio mass spectrometry (HRGC-C/P-IRMS) of pineapple (Ananas comosus L. Merr.) volatiles

Preston, C., Richling, E., Elss, S., Appel, M., Heckel, F., Hartlieb, A., Schreier, P.
Journal of agricultural and food chemistry 2003 v.51 no.27 pp. 8027-8031
pineapple juice, volatile compounds, odors, flavor compounds, gas chromatography, pyrolysis, mass spectrometry, stable isotopes, carbon, deuterium
By use of extracts prepared by liquid-liquid separation of the volatiles from self-prepared juices of pineapple fruits (Ananas comosus) (n = 14) as well as commercial pineapple recovery aromas/water phases (n = 3), on-line capillary gas chromatography-isotope ratio mass spectrometry was employed in the combustion (C) and the pyrolysis (P) modes (HRGC-C/P-IRMS) to determine the delta13C(VPDB) and delta2H(VSMOW) values of selected pineapple flavor constituents. In addition to methyl 2-methylbutanoate 1, ethyl 2-methylbutanoate 2, methyl hexanoate 3, ethyl hexanoate 4, and 2,5-dimethyl-4-methoxy-3[2H]-furanone 5, each originating from the fruit, the delta13C(VPDB) and delta2H(VSMOW) data of commercial synthetic 1-5 and "natural" (biotechnologically derived) 1-4 were determined. With delta13C(VPDB) data of pineapple volatiles 1-4 varying from -12.8 to -24.4 ppt, the range expected for CAM metabolism was observed. Compound 5 showed higher depletion from -20.9 to -28.6 ppt. A similar situation was given for the delta2H(VSMOW) values of 3-5 from pineapple ranging from -118 to -191 ppt, whereas 1 and 2 showed higher depleted values from -184 to -263 ppt. In nearly all cases, analytical differentiation of 1-5 from pineapple and natural as well as synthetic origin was possible. In general, natural and synthetic 1-5 exhibited delta13C(VPDB) data ranging from -11.8 to -32.2 ppt and -22.7 to -35.9 ppt, respectively. Their delta2H(VSMOW) data were in the range from -242 to -323 ppt and -49 to -163 ppt, respectively.