2.6. Volatile compounds analysis
Samples from unskinned semimembranosus muscle surface (1 cm
thickness) were collected from fully matured dry-cured hams (≈20
months processing time), vacuum-packaged and stored at −20 °C
until analysis. Frozen samples were minced and 1.5 g placed in a
20 ml glass vial sealed with a PTFE septum. Volatile organic compounds
(VOCs) were extracted by using a solid-phase microextraction (SPME)
device with a 75 μm CAR-PDMS coating (Supelco, Bellafonte, PA).
Prior to analysis, the fibre was preconditioned at 300 °C for 40 min at
the GC injection port. The vials were conditioned in the TriPlus
autosampler at 40 °C for 15 min. Then the fibre SPME was exposed to
the headspace for 30min. A gas chromatograph Trace GC (Thermo Electron
Corporation) equipped with mass detector DSQ II (Thermo Electron
Corporation) was used with a DB-5 capillary column (Supelco:
30 m, 0.25 mm i.d., 0.25 μm thickness). The injection was in split
mode (1:15). Helium was used as a carrier gas at 1.3 ml/min. The temperature
programmewas isothermal for 15min at 36 °C, then increased
to 120 °C at 4 °C/min, and then from120 to 250 °C at 20 °C/min. Injector
and detector temperatures were set at 250 °C.
Themass spectra were obtained by means of a mass selective detector
working in electronic impact at 70 eV, a multiplier voltage of 1650
and collecting data at a rate of 1.4104 scan/sec over the range 36–
360 uma. Compounds were identified by comparing their mass spectra
with reference spectra from the NIST 2005 version 2.0 spectral library
2.6. Volatile compounds analysisSamples from unskinned semimembranosus muscle surface (1 cmthickness) were collected from fully matured dry-cured hams (≈20months processing time), vacuum-packaged and stored at −20 °Cuntil analysis. Frozen samples were minced and 1.5 g placed in a20 ml glass vial sealed with a PTFE septum. Volatile organic compounds(VOCs) were extracted by using a solid-phase microextraction (SPME)device with a 75 μm CAR-PDMS coating (Supelco, Bellafonte, PA).Prior to analysis, the fibre was preconditioned at 300 °C for 40 min atthe GC injection port. The vials were conditioned in the TriPlusautosampler at 40 °C for 15 min. Then the fibre SPME was exposed tothe headspace for 30min. A gas chromatograph Trace GC (Thermo ElectronCorporation) equipped with mass detector DSQ II (Thermo ElectronCorporation) was used with a DB-5 capillary column (Supelco:30 m, 0.25 mm i.d., 0.25 μm thickness). The injection was in splitmode (1:15). Helium was used as a carrier gas at 1.3 ml/min. The temperatureprogrammewas isothermal for 15min at 36 °C, then increasedto 120 °C at 4 °C/min, and then from120 to 250 °C at 20 °C/min. Injectorand detector temperatures were set at 250 °C.Themass spectra were obtained by means of a mass selective detectorworking in electronic impact at 70 eV, a multiplier voltage of 1650and collecting data at a rate of 1.4104 scan/sec over the range 36–อุมา 360 ระบุ โดยการเปรียบเทียบของแรมสเป็คตรามวลสารมีแรมสเป็คตราอ้างอิงจาก NIST 2005 รุ่น 2.0 สเปกตรัมรี
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