| In order to study the relationship of color parameter values with maturity of tobacco leaves and the influences on its sensory quality of different maturity treatment of flue-cured leaves after aging,the change of color parameter values and chemical compositions of middle leaves during maturation process was explored.The chemical compositions,appearance quality,economic characteristics,sensory quality and comprehensive quality was tested and the change of sensory quality of different maturity of flue-cured tobacco leaves after aging was analyzed.The main result showed that:(1)The color parameter L*,a*,b*,C* values overall increased,while H* values reduced during maturation process.The color parameter L*,a*,b*,C* values were maximum and H* values were minimum when tobacco leaves had been harvested.The chlorophyll content of tobacco leaves reduced with the maturity stage moving forward and showed an opposite trend of the change of L*,a*,b*,C* values.The carotenoids content increased first and then reduced.The ratio of carotenoids to chlorophyll increased and showed an opposite trend of the change of H* values.The contents of total nitrogen to nicotine reduced first,then increased,reduced again and finally increased,which reached the maximum in 73 d after transplanting.The content of total sugar reduced first then increased and finally reduced.The content of reducing sugar reduced rapidly then increased rapidly and finally reduced slowly.The content of total sugar to reducing sugar reached minimum when tobacco leaves had been harvested.(2)The difference and correlation analysis of color parameters values for tobacco leaves with different maturity showed that,L*,b*,C*,H* values could distinguish the different between yellow green area of 10~20% effectively of fresh tobacco leaves,however a* values distinguish the different ability was inaccurate.With the maturity of fresh tobacco leaves increased,the L*,a*,b*,C* values increased,while the H* values reduced.So L*,b*,C*,H* values can be used to effectivity indicate the changes of maturity of fresh tobacco leaves.The ratio of sugar to nicotine slowly reduced first,then reduced rapidly,finally increased up to a stable trend.The ratio of total nitrogen to nicotine increased first then reduced and finally increased.The correlation analysis between color parameter values and chemical compositions showed that there was significant correlation between pigment and the ratio of carotenoids to chlorophyll with color parameter values except L* values.The absolute values of correlation coefficients were larger than 0.82.The correlation between total sugar with L*,b* and C* values were significant negative.The correlation between chlorophyll,total sugar,reducing sugar,the ratio of sugar to nicotine and the ratio of total nitrogen to nicotine with L*?a*?b*?C* values were negative,while positive with H*.The correlation were positive between other chemical compositions with L*,a*,b*,C* values,while negative with H* values.Therefore,the values of color parameters were related to the maturity of tobacco leaves.It could indicate the changes of chemical compositions in the middle tobacco leaves of mature stage with the use of colorimeter.(3)The difference and correlation analysis of color parameters values of tobacco leaves with different maturity showed that,10~20% area of the color of yellow and green on tobacco leaves could be effectively distinguished with L*,b*,C*and H* values,while inaccurately with a* values.With the increase of the maturity of tobacco leaves the L*,a*,b* and C* values increased,while the H* values reduced.So L*,b*,C* and H* values could be used to indicate the changes of maturity of tobacco leaves with good accuracy.(4)The analysis of chemical compositions,appearance quality,economic characteristics,sensory quality and comprehensive quality of different maturity treatment for flue-cured tobacco leaves showed that,the coordination of chemical compositions was the best when L* value was 43.91~48.44,b* value was 24.11~33.34,C* value was 31.64~36.35 and H* value was 110.81~120.9.Appearance quality was the best when L* value was 60.96~69.73,b* value was 46.17~62.01,C* value was 46.26~67.04 and H* value was 93.65~97.09.Economic characteristics,sensory quality and comprehensive quality were the best with the chemical compositions and appearance quality in higher grade when L* value was 50.64~58.7,b* value was 36.86~45.95,C* value was 40.38~45.67 and H* value was 100.64~107.79.(5)The proving trial of the color parameters values range of mature flue-cured tobacco leaves showed that,compared with regular harvest process,the coordination of chemical compositions,sensory quality and comprehensive quality of tobacco leaves increased with the harvest according to the color parameters values(50.64~58.7 of L* value,36.86~45.95 of b* value,40.38~45.67 of C* value and 100.64~107.79 of H* value).Harvest with the guidance of colorimeter had good feasibility and repeatability.(6)The sensory quality of different maturity treatment of tobacco leaves had improved after aging.The quality and content of aroma,fullness degree,impurity smoke,concentration,clustering and provocative of each treatment had improved.Especially the sensory quality of T2 had improved a lot than the others.The sensory quality,aroma characteristics,taste characteristics and smoke characteristics of T3 treatment were the best among all the treatment.The sensory quality of T3 treatment was significantly higher than T2,while after 24 months of aging it was higher than T2 but there was no significant difference.Therefore during the aging process of 24 months,the sensory quality of tobacco leaves with worse maturity improved a lot than the others,while it was the best with suitable maturity. |
PDF Full Text Request