Effects of different nitrogen application rates on flavor component content and sensory quality of tobacco Honghuadajinyuan

Objectives Nitrogen nutrition is the leading factor in tobacco nitrogen metabolism, directly affects the contents and ratios of organic acids, phenols, petroleum ether extracts and lignin in tobacco leaves. Investigation of the aroma and sensory quality of tobacco cultivar Honghuadajinyuan (abbreviation as Hongda) under different nitrogen application rates will provide fertilization support for the cultivation of the tobacco cultivar．

Methods Field experiments were conducted using tobacco cultivar Hongda as test material in 2013 at Yuxi County and Dali County, Yunnan Province, China. Four nitrogen levels of N 0, 45, 90 and 135 kg/hm² (i.e. N₀, N₁, N₂, N₃) were setup. The aroma components and the sensory quality were measured.

Results Volatile acids in tobacco were found increasing accordingly with the increased nitrogen rate. Among all tested groups, all the volatile acid contents were found the highest with N₃ treatment in the samples from Dali, reported as 0.13%. The senior fatty acids and multiple organic acids were found highest with N₂ treatment, with the contents of 19.71 and 82.65 mg/g in Yuxi and 20.67 and 94.12 mg/g in Dali, respectively. The polyphenol contents were the highest in N₂ treatment. The contents of petroleum ether extracts increased with the N rate, arriving at peak value of 6.25% in Yuxi and 6.05% in Dali, respectively. The lowest lignin content was in N₂ treatment, with the value of 5.19% in Yuxi and 5.42% in Dali, respectively. The best aroma, flavor and sensory of tobacco leaves were obtained in N₂ treatment in all tested groups, the estimated scores in Yuxi samples and Dali samples were 77.4 and 78.1, respectively.

Conclusions At the nitrogen application rate of 90 kg/hm², the contents of volatile acids and petroleum ether extracts, senior fatty acids and multiple organic acid, phenolic substance are reasonable and the lignin contents are low, so the tobacco leaves are rich of pleasure aroma, tasted comfortable and less irritated odor.