Abstract:To understand the formation of gaseous aldehydes from pyrolysis of ethyl linoleate and the influence of amino acids in food matrix on the formation of these aldehydes, the technology of online pyrolysis-Cambridge pad filter-gas chromatography/mass spectrometry (Py-Cambridge Pad Filter-GC/MS) was utilized to investigate the gaseous compounds generated from the pyrolysis of ethyl linoleate alone and its co-pyrolysis with different ratios of L-proline or L-glutamic acid, and the changes in aldehydes were compared and analyzed. The results showed that: The pyrolysis of ethyl linoleate alone produced a large number of gaseous compounds, with aldehydes accounting for approximately 29.058%(hexanal 8.271%,(Z)-2-heptanenal 5.455%, pentanal 2.472%, (E,E)-2,4-decadienal 2.064%, (E)-2-octenal 1.825%, heptanal 0.969%, 4-oxononanal 0.852%, 2,4-dodecadienal 0.458%, 2-hexenal 0.396%, and (E,E)-2,4-nonadienal 0.098%). When L-proline was co-pyrolyzed with ethyl linoleate at a ratio of 0.5 mg∶1 μL, no aldehydes were detected in the gaseous components, however, at a ratio of 0.125 mg∶1 μL, (Z)-2-heptanenal was detected (6.862% of that from ethyl linoleate pyrolyzed alone) could be detected in the gaseous components. When L-glutamic acid and ethyl linoleate were co-pyrolyzed at ratios of 0.5 mg∶1 μL and 0.125 mg∶1 μL, hexanal and (Z)- 2-heptanenal were detected in the pyrolyzed products. Therefore, the online Py-Cambridge Pad Filter-GC/MS technique could efficiently analyze the gaseous aldehydes formed during the pyrolysis of ethyl linoleate. The formation of gaseous aldehydes is significantly influenced by the type and ratio of amino acids when co-pyrolzed with ethyl linoleate.
