Changes in TSNA contents and sensory quality of ultra-low nicotine tobacco leaves produced by grafting with eggplant
Ultra-low nicotine tobacco production has been given broad attention due to the possible regulation of nicotine content in cigarette tobacco. Based on grafting with eggplant (eggplant as rootstock, flue-cured variety Yunyan 87 as scion), the feeding selection behaviour of budworms (Heliothis assulta) was compared between ultra-low nicotine tobacco and regular tobacco leaves, and the content of TSNAs and neutral aroma components, smoke parameters and sensory quality of cigarettes were also determined and evaluated. Tobacco samples were from the following three treatments: “tobacco / tobacco”, “tobacco / eggplant without earthing up”, “tobacco / eggplant with earthing up”. The results showed that in the enclosed environment, budworms preferred ultra-low nicotine tobacco leaves to regular tobacco leaves, and the budworms began to feed on the regular tobacco leaves only after the ultra-low nicotine leaves had been eaten up. The contents of NNN, NNK, NAT and total TSNAs in ultra-low nicotine tobaccos were reduced dramatically, with NNN, NNK and TSNAs contents in upper leaves from tobacco / eggplant without earthing up being 82.7 %, 79.5 % and 68.8 % lower than that of regular tobacco, respectively, and being 79.7 %, 79.8 % and 68.6 % lower for middle leaves. The differences in content of neutral aroma components were not significant. Nicotine content in mainstream cigarette smoke made from ultra-low nicotine tobacco was markedly lower than that in control cigarettes, while there were no significant differences in total particle matter, moisture, CO, tar level and puff number. There were no significant differences in aroma quality, smoke density, irritation and combustibility, while the aroma quantity, odour score and after taste were decreased to some extent. Significant reductions were perceived for strength, consumer satisfaction and acceptance. The results showed that the selective reduction of nicotine by grafting had different impacts on leaf and smoke chemistry and sensory parameters.