Quantitation of hexanal by automated SPME for studying dietary influences on the oxidation of pork

Automated headspace solid-phase micro-extraction gas chromatography (auto-HS-SPME-GC) was employed to determine the hexanal content of ground pork shoulders from pigs raised on a normal corn diet and a corn diet high in oil and monounsaturated fatty acids. This external standard method showed good linearity (R2=0.999) and acceptable reproducibility (rsd=6.7%). Samples were stored refrigerated under light and analyzed on days 0, 3, 5, 7 and 9. Although no significant differences were observed between treatments in hexanal concentration, color, odor, or thiobarbituric acid-reactive substances (TBARS) value, TBARS and hexanal values increased over time, which became significant on days 7 and 9 for TBARS and on day 9 for hexanal. TBARS and hexanal concentration were correlated with R2 values of 0.992 and 0.804 for the treatment and control group, respectively. Auto-HS-SPME-GC provided a rapid and convenient method for monitoring the hexanal content of raw ground pork. HS-SPME using Carboxen/PDMS stable flex fiber provided the required sensitivity, linearity and reproducibility for measurement of hexanal in the headspace of raw ground pork.