The Effect Of Degradation Of Faty Acid And Pigment And Quality Of Obacco Leaf During Flu-Cured

The experiments were carried out, through regulating the applied flue-curing conditions, to evaluate the faty acid ,chlorophyll ,carotinoid degradation and it's relationship to lipoxygenase activity quality in tobacco leaf. It was found out that during fiu-cured, with the proceeding of curing ,the disappear of the water, the lox activities increase slowly during 0-24 hour. It increase quickly during 24-48 hour. It reach the peak after curing 48 hour. Then it obviously decrease. At last, it disappeared. In the procession of tobacco turning yellow by curing,the Lipoxygenase activities ,the content of superoxide radical anion and ABA increase gradually during 0-24 hour and increase quickly during 24-48 hour, until reach peak then begin to reduce. Under different moisture condition, lipoxygenase activity and sic acid (ABA) are related to each other. Coeffectients are respectively 0.88\ 0.82\ 0.81.The content of faty acid,carotinoid,chlorophll and lipoxygenase activity had different changing models. With the position of curing their content increased slowly at first24 hour,at second 24 hourjncrease quickly ,then dcrease.they are related to lopoxygenase activity . ABA and MDA had close correlation to lipoxygenase. Under different moisture condition, the correlation was significant at the 5% level of significance between faty acid and the degradation of them and carotinoid degradation of them,ipoxygenase are related each other, under different moisture. The correlationbetween faty acid and lipoxygenase under different curing condition.There were big effects of temperature and moistrue conditions in curing process on faty acid compounds content in tobacco leaf. The studies indicated that total faty acid content was higher in tobacco leaf cured under high temperature yellowing (HTY), low moisture yellowing (LMY) or low moisture color-fixing (LMC) conditions. The curing temperature had less effect on faty acid than curing moisture. The faty acid content was high in tobacco leaf cured under high moisture yellowing (HMY).The degradation of faty acid,carotinoid,chlorophll and lipoxygenase activity and the accumulation of them were mainly occurring in yellowing stage and color fixing stage, faty acid,carotinoid,chlorophll content was degraded more quickly in yellowing stage than in color-fixing stage and the degradation of them was on the contrary. That's to say, the degradation of protein and the accumulation of faty acid didn't happen paralleledly. Under the conditions of LTY, HMY and HMC, the lipoxygenase activity was high and could standing much longer time which resulted in more activity was hydrolyzed and more the degradation of them was accumulation. And that's the reason why the content of faty acid and carotinoid was low and the content of degradation of them was high in the tobacco leaf cured under these conditions. Also, the condition of LTY and HMY made for the lipoxygenase activity and the accumulation of them. The content of the degradation of them increased synchronously and reached the highest point at the end of color fixing and then decreased.Correlation analysis showed that the correlation among total faty acid, carotinoid, cholorophll, carotinoid was highly significant at 1% level.After considering the above-motioned study results synthesizly, we think that the loe moisture and low temperture yellowing or high moisture curing condition is good forthe quality of tobacco leaf.