Following volatile aromatic substances were quantified: ethyl (E,Z)-2,4-decadienoate, methyl (E)-geranoate, isoamyl acetate, ethyl hexanoate, ethyl octanoate, isoamyl octanoate, ethyl decanoate, and ethyl dodecanoate.
In addition to the relevant aroma compounds--isoamyl acetate, ethyl hexanoate, ethyl octanoate, isoamyl octanoate, ethyl decanoate, methyl (E)-geranoate, ethyl dodecanoate, and ethyl (E,Z)-2,4-decadienoate--other methyl and ethyl esters of cis-trans isomers of decadienoic acid were also determined according to Brandes et al.
The polar compound isoamyl acetate produced no response with respect to PDMS fibre as well as ethyl (E,Z)-2,4-decadienoate with respect to polyacrylate.
In 2012, four compounds--1-hexanol, hexyl acetate, ethyl phenyl acetate, and terpinolene--decreased with crop reduction, while ethyl acetate and [beta]-damascenone increased.
As to esters, ethyl acetate was unaffected (see "Ethyl Acetate and Isoamy Acetate"), while isoamyl acetate and ethyl caproate decreased in 2011 relative to delayed harvest date.
Ethyl butyrate, phenyl ethyl alcohol, citronellol, geraniol and (3-damascenone were reduced in concentration by cluster thinning in 2012 but were not impacted in 2011.
The final synthetic grape essence mixture contained 3.0 [micro]L ethyl propionate, 2.0 [micro]L ethyl butyrate, 0.3 [micro]L ethyl 2-methylbutyrate, 0.1 [micro]L D-limonene, 0.16 g benzoic acid, 7.0 [micro]L methyl anthranilate, 0.3 [micro]L ethyl decanoate, 7.0 [micro]L dimethyl anthranilate, and 4.4 [micro]L ethyl dodecanoate dissolved 100 mL of a 10% Tween 85 in RO water.
All 11 chemicals identified by GC-MS have above 90% computer matches to mass spectra in the NIST 98 Library of Mass Spectra and Subsets except ethyl propionate which had a 64% match (Table 1).
An internal standard of 500 pmol of ethyl heptadecanoate (Nu Chek Prep) was added to 1 mL of the homogenate along with 2 mL of cold acetone.
Single-ion monitoring was performed to quantify appropriate base ions for individual FAEEs: ions 67, 88, and 101 for ethyl palmitate, ethyl heptadecanoate, ethyl stearate, ethyl oleate, and ethyl linoleate; and ions 79, 91, and 117 for ethyl arachidonate, ethyl eicosapentaenoate, and ethyl docosahexaenoate.
Specifically, the following have been shown: (a) the enzymatic parameters for FAEE synthesis by acyl-CoA:ethanol acyltransferase in human and rat liver microsomes are similar (11,12 ); (b) FAEEs and FAEE synthase are found in rat and human adipose tissues after ethanol intake with a similarly long half-life of -16 h after cessation of ethanol intake (13,14); (c) ethyl oleate as a representative FAEE in both human and rat LDL is degraded similarly by rat liver, and the oleate is directed after hydrolysis toward triglycerides in both humans and rats (1015); (d) ethyl oleate as a representative FAEE within human LDL was degraded in both human and rat blood over a 30-min incubation (10).
A 50-[micro]L (1 nmol) internal standard of ethyl heptadecanoate (E17:0) was added to each sample.