Study On Extraction Of Low-grade Tobacco Extract And Essential Oil And Its Application In Cigarette Flavoring

China is one of the major producing areas of tobacco,which means plenty of low-grade tobacco leaves are produced every year.If just abandoning or burning them casually,it will not only waste resources but also pollute the environment.Employing advanced extracting techniques to gain low-grade tobacco leaf extracts is an effective way to reuse of tobacco resources and broaden the field of tobacco application.In this paper,we took low-grade tobacco leaf as the object of research and researched extraction conditions for tobacco extract and oil,studied the volatile constituent,functional activities and flavoring effects in cigarette of tobacco extracts.The main research results are as follows:1.The yields of the extracts using ethanol extraction,soxhlet extraction and enzymatic extraction were 50.53 ± 0.11%,8.83 ± 0.07% and 65.30 ± 1.12%respectively.In terms of physical and chemical parameters,the alcoholic extract was superior to the other two.From the point of view of industrial application,the ethanol extraction method has the advantages of low process cost,high ethanol recovery and avoidance of toxic reagents.In the identification of volatile components and analysis of aroma vitality values(ROAV),a total of 68 substances were extracted from the three infusions,including 44 by ethanol extraction,33 by soxhlet extraction and 32 by complex enzyme extraction.11 substances were extracted simultaneously by the three methods,namely: 2-acetyl pyrrole,nicotine,ketone,damascenone,geranylacetone,dihydrokiwi lactone,megastrienone,neophytadiene methyl palmitate,methyl linoleate and ethyl oleate.They are the key aroma-causing components of tobacco infusions and play a role in softening the smoke and enhancing the fineness of the smoke in cigarette flavouring.The content of alcohols,aldehydes and ketones in the infusion extracted by the enzymatic method was higher than the other two methods,but the content of esters,olefins and nicotine was the lowest;the highest content of nicotine in the infusion obtained by the soxhlet extraction method was 76.06%,but the substance content of the other components was the lowest;only the ethanol extraction method had a high content of all types of components,and all 15 characteristic components were detected,with the concentration of nine characteristic components The concentrations of nine characteristic components were greater than their threshold values(ROVA > 1).In addition,the ethanol extraction method was the most effective in the sensory evaluation of cigarette flavouring and in the determination of antioxidant activity.In conclusion,the ethanol extraction method was the best extraction method among the three methods,with the best extraction conditions being 80% ethanol concentration,90°C extraction temperature,1:8(g/m L)material to liquid ratio,3 h extraction time and 50.53 ± 0.11% yield.2.The yields of tobacco essential oil extracted using water distillation,microwave assisted extraction and low eutectic solvent methods were 0.37 ± 0.09%,0.42 ± 0.02%and 0.52 ± 0.02% respectively.There were no significant differences between the three essential oils in terms of basic physical and chemical parameters and inhibition experiments.From the point of view of industrial application,the microwaveassisted extraction method has the advantages of short time,low energy consumption and low cost.In the analysis of volatile components and aroma vitality values(ROAV),a total of 54 substances were identified by GC-MS,including 40 by microwave assisted,39 by low eutectic solvent and 32 by water distillation;21 substances were detected simultaneously by the three methods,including: 2 olefins,7 esters,10 ketones,1 alkane and 1 fatty acid.The most critical aroma-causing components of tobacco essential oils were damascenone,β-violone,methyl palmitate,geranylacetone and linalool.In the comparison of the content of the characteristic components,only all 11 characteristic components were detected in the essential oils obtained by microwave-assisted extraction,with five characteristic components having concentrations greater than their threshold values(ROVA > 1).The composition of the essential oil samples obtained by water distillation and microwave-assisted extraction was similar;the essential oil obtained by the low eutectic solvent method contained 71.67% of new phytadiene,while the alcohols,esters and ketones were lower;the microwave-assisted extraction method yielded a higher content of characteristic components than both the water distillation and low eutectic solvent methods.In the sensory evaluation of cigarette flavouring,the microwave-assisted extraction method yielded the best results for essential oils.In summary,the microwave-assisted extraction method was the best method of essential oil extraction among the three methods,with optimum extraction conditions of 640 W power,10 min microwave time,1:8(g/m L)material-to-liquid ratio,2 h distillation time and a yield of 0.42 ± 0.02%.3.The biological activity of tobacco extracts was studied.In the antioxidant experimental system,all three essential oils and all three infusions showed strong antioxidant activity.Among the three essential oils,the scavenging capacity of the80% ethanol extracted tobacco extracts was higher than the other two.It was tentatively determined that the main components of the tobacco extracts with antioxidant activity were probably phenolics and flavonoids,followed by polysaccharides.Bacteriostatic experiments with the essential oils showed that all three tobacco oils have some antibacterial activity and are a good source of natural antibacterial agents.4.The use of tobacco extracts in cigarette flavouring was investigated.All three infusions and three essential oils had a significant effect on cigarettes in reducing oral irritation and enhancing the softness and richness of the smoke.Among them,the 80% ethanol extracted infusion and the essential oil extracted by microwave assisted method were the most effective.The two infusions and the essential oils were adapted for use in tobacco table aromas.Sensory evaluation showed that the formulation was effective in enhancing the amount of aroma,improving the texture,reducing impurities and making the cigarettes ripe and sweet.