Study On Improving The Water-holding Capacity And Sensory Quality Of Reconstituted Tobacco Sheet

The reconstituted tobacco(RT)is of great significance for the tobacco industry to save raw materials and reduce costs.It is playing an increasingly important role in reducing the harm and improving the quality of cigarette.The domestic RT has some disadvantages compared with foreign products,mainly in: dry and irritating smoke,lack of coordination,smell of wood,which has limited the application of RT in cigarette products.Therefore,in this study,to improve the water-holding capacity and sensory quality of RT,firstly,the influence factors of equilibrium moisture content(EMC)and moisture content in mainstream smoke(MSMC)were analyzed,and suitable technological formula was determined by the addition test and consideration of related properties.Next,in order to further reduce the irritation,enzyme preparation was used for degradation of macromolecular substances.The main findings and results were last as follows:Firstly,EMC and MSMC of 16 RTs were determined,the correlation analysis found that MSMC and EMC were significantly positive correlated.Thus,EMC could be used as scientific index for evaluating “smoke dryness” reducing capacity.With the decrease of relative humidity,EMC decreased.Under the same relative humidity,the EMC of different samples varied largely,which indicated that in addition to environmental humidity,the physical structure and chemical components of RT had an important effect on EMC.Thus,the physical structure and chemical components of 16 RTs were determined,then the influencing factors of RT's EMC were investigated by correlation analysis.The results showed that physical structure(specific surface area,specific pore volume and bore diameter),nicotine,total sugar,protein and other conventional ingredients and cellulose had no significant effect on the EMC.Potassium,chlorine and pectin were in favor of EMC.There was a significant negative correlation between calcium carbonate,ash and EMC.Further analysis showed that there was a remarkable negative correlation between MSMC and ash,calcium carbonate,the correlation coefficient was-0.743 and-0.787,respectively.So,the high addition level of calcium carbonate could have bad effect on the sensory quality of RT.To verify the conclusion of the second chapter,6 kinds of RT with different addition level of calcium carbonate were prepared.It is proved that calcium carbonate was significantly negatively correlated with the EMC in all relative humidity environment and the correlation coefficient were all above 0.9.With the increase of calcium carbonate,MSMC was reduced significantly.At the same time,the effects of calcium carbonate on other properties of RT were investigated.The results showed that with the increase of calcium carbonate,NFDPM,CO decreased,but it could also lead to decrease of calcium carbonate retention rate,tensile strength.The filling value reaches the maximum at 15% addition level.Thermogravimetric analysis showed that addition of calcium carbonate reduced the weight loss of second,third stage of the RT pyrolysis,increase weight loss of forth stage and the residual ash.The results of sensory evaluation showed that the best effect was achieved when the addition level was 15%.Taking account of above evaluation indexes,the appropriate calcium carbonate addition level was 15%.On the basis of the optimized formula,in order to further reduce the irritation,enzyme preparations were used to degrade the precursors of irritating substances,such as pectin and protein.The optimal conditions for solo enzyme treatment were obtained from single factor experiments,for protease: enzyme dosage was 200 U/g,the time was 3 h,and for pectinase: enzyme dosage was 400 U/g,the time was 3h,at natural pH.Based on single factor experiments,optimal condition for simultaneous treatment was obtained from orthogonal test: protease dosage was 300 U/g and pectinase dosage was 400 U/g,the time was 2 h.The effects of different enzymatic methods on RT were further investigated by systematic comparisons of 3 methods: simultaneous treatment(PP),treat with protease firstly and then pectinase(PrE-PE),treat with pectinase firstly and then protease(PE-PrE).The results showed that,extraction rate were all improved via treatment,the highest extraction rate could be obtained by PE-PrE treatment.TGA revealed that,after enzyme treatment,the pyrolysis effects of pectin and other macromolecules decreased;the combustion effect became stronger.As for the smoke routine constituents,with exception of PP treatment,TPM and NFDPM of two kinds of treatments decreased;CO,nicotine of three treatments were reduced;MSMC and puff number increased.FTIR analysis showed that,after the treatment,carbonyl compounds and CO content decreased significantly,especially in the two step enzymolysis.After treatment,except for the same NH3 level of PrE-PE with control,NH3 were significantly increased in the others,PE-PrE treatment had the highest level.Through GC-MS,it was found that: the enzymolysis had a positive effect on flavor,the aroma components contents of PrE-PE,PE-PrE and PP increased by 23%,9% and 16%,respectively.Sensory evaluation showed that,PrE-PE treatment had the best sensory quality,and the sensory quality of PE-PrE was poor.By considering all the indexes,the PrE-PE was the best which could reduce the smoke irritation,and obtain good sensory quality at the same time.