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The composition and content of aroma substances in flue-cured tobacco (Nicotiana tabacum L.) will affect the quality of tobacco. To investigate the correlation between various aroma substances of K326 before and after flue-curing, and their impact on tobacco quality and diversity, this study employed the middle leaves of K326 and KRK26 as test materials. Samples were collected both before and after flue-curing for untargeted metabolomics analysis. The results of K326 showed that 584 metabolites were significantly different and there were 44 aroma-related metabolites, including alcohols, aldehydes, phenols, organic acids, etc. The analyzed aroma compounds consist of 37 known tobacco aroma substances, while 7 metabolites, previously not associated with tobacco aroma, have been identified as aroma substances in other food products. These findings suggest that these seven metabolites might may be potential tobacco aroma compounds. Further analysis showed that the content of phenols, alcohols, and aldehydes increased significantly after flue-curing, but the content of organic acids decreased. Furthermore, the analysis of KRK26 revealed a correlation between the quantity of aroma substances and the type of tobacco. These findings serve as a reference for enhancing the flue-curing process of K326 and optimizing the industrial production of cigarettes that use cured K326 tobacco leaves.

Nitrogen fertilizer is essential for the yield and quality of flue-cured tobacco. Honghuadajinyuan (i.e. Hongda) is a special flue-cured tobacco variety in Yunnan, which differs in nitrogen application rates from other varieties. In 2016 and 2017, different nitrogen application rates were established in Yunnan to compare, with other varieties, Hongda's agronomic, economic, chemical indicators and soil residual nitrogen. As nitrogen fertilizer rate increased, the ratio of fresh weight to dry weight (RFD) and the proportions of inferior tobacco (PIT) initially decreased and then increased in contrast to the proportions of superior tobacco (PST) and average price. Total sugar and reducing sugar contents in flue-cured tobacco leaves decreased as nitrogen fertilizer rate increased, while total nitrogen, nicotine, and protein contents increased. The highest sensory evaluation scores were obtained with 45 and 60 kg N ha−1. Soil nitrate contents increased with increasing nitrogen fertilizer rate and significantly increased when nitrogen application rate exceeded 60 kg N ha−1. A quadratic model was suitable for Hongda's response to nitrogen fertilizer rate and 60 kg N ha−1 can meet the needs of the growth of this flue-cured tobacco variety. Abbreviations: Hongda: Honghuadajinyuan; RFD: ratio of fresh to dry weight; PIT: proportion of inferior tobacco; PMT: proportion of medium tobacco; PST: proportion of superior tobacco; SPAD: soil and plant analyzer development. [ABSTRACT FROM AUTHOR]

• It was first time to evaluate different tobacco types for heated cigarettes. • Total score of Tiandeng tobacco was highest in heated cigarettes. • Total alkaloids were positively correlated with the total sensory evaluation. • Total polyphenols were positively correlated with the total sensory evaluation. • Aldehydes have a negative correlation with the total sensory evaluation score. Heated tobacco (Nicotiana tabacum L.) products develop rapidly because of its low toxicity. In order to evaluate the industrial applicability of the existing types of characteristic tobacco as raw materials for heated tobaccos, this research ascertained differences in the main chemical compositions in tobacco leaves from different types to establish a relationship between chemical composition and sensory evaluation to select types suitable for producing heated tobaccos. Nine tobacco types (K326, Yunyan 97, Cherry-red tobacco, Han tobacco, Dao tobacco, Tiandeng tobacco, Sun-cured yellow tobacco, fresh-cut tobacco, and aromatic tobacco) planted in Yunnan Province, China were selected. Their sensory quality was evaluated by the method for sensory evaluation of heated tobaccos and chemical composition and content of aroma substances in tobacco leaves were determined. In the evaluation of sensory quality of heated tobaccos, the total score of Tiandeng tobacco was significantly higher than those of the other types, followed by Cherry-red tobacco and K326; There were significant differences in chemical composition in the nine tobacco types and the total alkaloid content in Cherry-red tobacco was notably higher than in the other tobacco types. The amounts of total sugar, reducing sugar, and starch in Han tobacco were significantly lower than other types, while the amounts of total nitrogen, potassium oxide, chloride ions, and protein were much higher than in the other tobacco types. The total amounts of polyphenols and aroma compounds in fresh-cut tobacco were significantly higher than in the other tobacco types. The contents of nornicotine, neonicotine, anatabine, and total alkaloid showed a significant positive correlation with the total sensory evaluation score. The contents of nicotyrine and 2,3-bipyridine were significantly and negatively correlated with the total sensory evaluation score. A remarkable negative correlation was found between starch content and score on irritation. Furthermore, the amounts of neochlorogenic acid, chlorogenic acid, caffeic acid, and total polyphenols were significantly and positively correlated with the total sensory evaluation score. The amounts of aldehydes and phenolic compounds had a significant negative correlation, while the amount of olefin compounds had a significant positive correlation, with the total sensory evaluation score. These chemicals in tobacco leaves can be used as in analyses screening of other suitable tobacco types, and as reference standards for selecting tobacco raw materials suitable for high-quality heated tobaccos. [ABSTRACT FROM AUTHOR]

Tobacco ( Nicotiana tabacum L.) is a major cash crop, and soil quality played a significant role in the yield and quality of tobacco. Most farmers cultivate tobacco in rotation with other crops to improve the soil characteristics. However, the effects of different previous crops on the soil's nutrient status and bacterial community for tobacco cultivation still need to be determined. Three treatments were assessed in this study, i.e., tobacco-planting soil without treatment (CK), soil with barley previously cultivated (T 1 ), and soil with rapeseed previously cultivated (T 2 ). The soil physical and chemical properties and the 16S rRNA gene sequence diversity of the bacterial community were analyzed. The effects of different crops on the physical and chemical properties of tobacco-planting soil and the diversity and richness of the bacterial community were comprehensively discussed. The results of this study showed that different previously cultivated crops altered the nutrient status of the soil, with changes in the ratio of NH 4 + -N to NO 3 - -N having the most significant impact on tobacco. In CK, the ratio of NH 4 + -N to NO 3 - -N was 1:24.2, T 1 -1:9.59, and T 2 -1:11.10. The composition of the bacterial community in tobacco-planting soil varied significantly depending on the previously cultivated crops. The richness and diversity of the bacterial community with different crops were considerably higher than without prior cultivation of different crops. The dominant bacteria in different treatments were Actinobacteriota, Proteobacteria, and Chloroflexi with their relative abundance differed. In conclusion, our study revealed significant differences in nutrient status, bacterial community diversity, and the richness of tobacco-planting soil after the preceding cultivation of different crops. Suitable crops should be selected to be previously cultivated in tobacco crop rotations in near future for sustainable agriculture., Competing Interests: ML, DW, YH, and JS were employed by Dali Prefecture Branch of Yunnan Tobacco Company. RX was employed by Weishan City Branch of Yunnan Tobacco Company. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Liu, Xue, Wang, Hu, Gu, Yang, Zhao, Guan, Su and Jiang.)

Organic fertilizer is effective in improving soil quality, and promoting crop growth. Combined organic and inorganic fertilization has been proved as a more favorable way to tobacco yield and quality. However, the mechanisms underlying tobacco yield and quality under combinations of different organic and inorganic fertilizer remain unclear. We conducted a 12-year tobacco ( Nicotiana tabacum L.)-maize crop rotation field experiment in Yanhe experimental station, China to examine the yields and qualities of tobacco, soil nutrients, and extracellular enzyme activities associated with carbon, nitrogen, and phosphorus cycles in response to different fertilization treatments. Five fertilization treatments (no fertilization; 75 kg N fertilizer ha -1 ; 450 kg oil cake ha -1 + 75 kg N fertilizer ha -1 ; 15,000 kg pig dung ha -1 + 60 kg N fertilizer ha -1 ; 3,000 kg straw ha -1 + 75 kg N fertilizer ha -1 ) were applied to tobacco while maize was fertilized with inorganic compound fertilizers. After 12 years of tobacco-maize rotation, the results showed that organic fertilizer additions elevate tobacco yield and quality, and the soil extracellular enzymes activities. Gram-negative bacteria, actinomycetes, and total soil microbial biomass were increased by organic fertilizer additions, both plant-based (oil cake and straw) and animal-based (pig dung) organics. The levels of soil organic matter, total organic carbon, total phosphorus and available phosphorus are higher in pig dung addition treatment than oil cake and straw additions. By variance analysis with respect to fertilization treatments, organic sources differentially affected the activities of diverse soil enzymes. The redundancy analysis gave that yield and quality of tobacco leaves (upper, middle, and lower leaves) positively related to soil extracellular enzyme activities. Based on analysis of yield and quality of tobacco leaves with extracellular enzyme activities and soil nutrients, it is suggested animal-based organic fertilizer, thus pig dung, should be used in combining with chemical fertilizers to improve the quality of tobacco and soil nutrients., Competing Interests: Author CZ was employed by Yunnan Tobacco Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Jiang, Zhang, Zhang, Su, Cong and Deng.)