Abstract SCHIRACK, ANDRIANA VAIS. The Effect of Microwave ...

Gold mass spectrometer (MS; Perkin Elmer Life and Analytical Sciences, Inc.,
Wellesley, MA). The injector temperature was maintained at 150 °C. Separations
were performed on a fused silica capillary column (ZB-5, 30 m x 0.25 mm i.d., 1.0
µm df,; Phenomenex, Torrance, CA). The GC oven temperature was programmed to
increase from 35 °C to 300 °C at a rate of 15 °C/minute with an initial and final hold
time of 1 minute each. The carrier gas was helium with a flow rate of 0.83
mL/minute, and the flow was split at a 20 to 1 ratio. Mass spectrometer conditions
were as follows: capillary direct interface temperature, 270 o C; ionization energy, 70
eV; mass range, 50-300 a.m.u; EM voltage (Atune+306 V); scan rate, 0.5 scans/s.
Each sample was evaluated in duplicate.
Solvent extraction with solvent assisted flavor evaporation (SAFE)
Compounds of a higher molecular weight were screened using a solvent
extraction/SAFE technique to determine if they contribute to the microwave-related
off-flavor. One hundred grams of peanut paste was weighed and placed in Teflon
bottles. Then, 100 mL of ethyl ether, 100 mL saturated sodium chloride solution, and
2.45 ppm of internal standard (comprised of 2-methyl-3-heptanone and 2-methyl
pentanoic acid in methanol) were added. The mixtures were shaken for 30 minutes
on a Roto mix (Type 50800; Thermolyne Dubuque, IA) at high speed. The bottles
were then centrifuged at 3000 rpm for 15 min in order to separate the solvent phase
from the mixture, which was subsequently transferred to a glass jar. The procedure
was repeated twice with the addition of 100 mL of ethyl ether to the sample each
time.
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