Determination of hydroxylated fatty acids from the biopolymer of tomato cutin and their fate during incubation in soil.
BACKGROUND
The plant cuticle is a thin, predominantly lipid layer that covers all primary aerial surfaces of vascular plants. The monomeric building blocks of the cutin biopolymer are mainly ω-hydroxy fatty acids.


OBJECTIVE
Analysis of ω-hydroxy fatty acids from cutin isolated from tomato fruits at different stages of decomposition in soil. Different derivatives and mass spectrometric techniques were used for peak identification and evaluation.


METHODS
Preparation of purified cutin involving dewaxing and HCl treatment. Incubation of purified cutin for 20 months in soil. Pentafluorobenzoyl derivatives were used for GC/MS operated in the electron capture negative ion (ECNI) mode and trimethylsilyl ethers for GC/MS operated in the electron ionisation (EI) mode for analysis of ω-hydroxy fatty acids.


RESULTS
Six ω-hydroxy fatty acids were detected in the purified cutin, three of which were identified as degradation products of 9,16-dihydroxyhexadecanoic acid as a consequence of the HCl treatment involved in the purification step. Incubation of the isolated cutin in soil was accompanied with decrease in concentration of all hydroxyl fatty acids.


CONCLUSIONS
We produced evidence that the HCl treatment only affected free hydroxyl groups and thus could be used for proportioning free and bound OH-groups on cutin fatty acids. The method enabled a direct quantification of the ω-hydroxy fatty acids throughout the incubation phase.
Hauff
Simone
S
Universität Hohenheim, Institut für Lebensmittelchemie, Garbenstr. 28, D-70593 Stuttgart, Germany.
Chefetz
Benny
B
Shechter
Michal
M
Vetter
Walter
W
D001673:Biodegradation, Environmental; D001704:Biopolymers / Q000032:analysis; D004952:Esters / Q000032:analysis; D005227:Fatty Acids / Q000032:analysis* / Q000302:isolation & purification; D008401:Gas Chromatography-Mass Spectrometry; D006865:Hydrogenation; D006900:Hydroxylation; D007202:Indicators and Reagents; D018551:Solanum lycopersicum / Q000737:chemistry*; D013058:Mass Spectrometry; D008563:Membrane Lipids / Q000737:chemistry* / Q000302:isolation & purification; D012987:Soil / Q000032:analysis*; D021241:Spectrometry, Mass, Electrospray Ionization; D014297:Trimethylsilyl Compounds / Q000737:chemistry
D001704:Biopolymers; D004952:Esters; D005227:Fatty Acids; D007202:Indicators and Reagents; D008563:Membrane Lipids; D012987:Soil; D014297:Trimethylsilyl Compounds; C000521:cutin