Py-GC-MS Investigation of Pyrolysis Behaviours and Decomposition Products of alpha- and beta-2,7,11-Cembratriene-4,6-Diols

To study the thermal stability of cembratriene, alpha- and beta-2, 7, 11-cembratriene-4, 6-diols (alpha- and beta-CBT) were isolated from tobacco leaves.Thermogravimetric (TG) and differential thermogravimetric (DTG) analyses were used to evaluate the cleavage differences between the two compounds. The TGA results showed the peak temperatures (T-p) were 263.3 degrees C and 254.1 degrees C with the largest weight loss rate; the significant weight losses were 90.96% and 99.45%. Pyrolysis gas chromatography-mass spectrometry (Py-GC-MS) was employed for the pyrolysis products at different temperatures (300, 600, and 900 degrees C) under either N-2 or an O-2-N-2 (10%:90%) mixture. The results showed that the major pyrolysates from (alpha- and beta-CBT were simple hydrocarbons, such as toluene, 1, 4-pentadiene, and p-xylene, as well as several important flavour compounds, such as 2-methylfuran, benzaldehyde, and 4-methylbenzaldehyde. More pyrolysis products were obtained at higher temperatures, and almost all of the harmful aromatic ingredients were produced at 900 degrees C. Importantly, solanone, a significant flavour component, was only obtained from the pyrolysis of alpha-CBT under 10% O-2 in N-2 at both 600 and 900 degrees C. The number of the pyrolysates changed with the change in pyrolysis temperature and the presence of oxygen. The study of the thermal behaviour and pyrolysis products of these terpenoids could possibly suggest flavour precursors that could be used to provide specific flavours.