Influence Of Picked-leaf Maturity On Curing Quality Of Flue-cured Tobacco Cultivar Honghuadajinyuan

Liangshan and panzhihua tobacco planting areas are the core bases of Honghuadajinyuancultivar in Sichuan province, and Honghuadajinyuan cultivar manifests an outstanding fen-flavorstyle on plateau. But it exists a puzzle about uncoordination between yellowed and dehydration ofleaf tending.This paper regulated and controlled the senescence degree and curing foundation of freshleaves by choosing different picked-leaf maturity as breakthrough, and studied the change rules oftobacco cell ultrastructure, the color, the dry and the carbohydrates during flue curing process andquality formation of flue-cured tobacco. The results were as follows.(1) The change rules of tobacco appearance quality of different picked-leaf maturity duringcuring were analyzed which showed that the picked-leaf maturity had some effect on fresh leavesand parameter variations of color features during curing. The mean of red, green and bluecomponents of color gradually increased along with maturity through the curing process andtobacco color changes were mainly caused by the red and green components and the bluecomponents changed gently.The changes of pigment and moisture content during curing were analyzed which showedthat the picked-leaf maturity had significant effect on pigment and moisture content during curing.The tobacco leaves of lower maturity had faster speed and larger amount of degradation than thoseof higher maturity. The change rule of amount and speed of water loss in tobacco leaves ofdifferent maturity was mature＞ripe＞over mature from the beginning of curing to the end ofthe color-fixing stage. The water loss speed was slower and amount was less during the yellowingstage and was in the contrary case during the color-fixing stage.(2) The changes of main chemical composition in tobacco leaves of3maturities duringcuring were analyzed which showed that the picked-leaf maturity had significant effect on starchdegradation. The starch content was high in fresh leaves and the rule of starch degradation speed and amount was mature＞ripe＞over mature. The change trend of total sugar and reducingsugar content in mature and ripe tobacco leaves was rise-reduce-rise and rising range was muchhigher than leaves over mature.The production rules of polyphenols during the flue curing were different along with thematurity. In fresh leaves, the chlorogenic acid content gradually reduced and rutin contentgradually increased and polyphenols content reduced first then increased. The polyphenols contentin mature tobacco leaves reduced at the beginning of curing, then at the color-fixing stage, thepolyphedols content in tobacco leaves of3maturities increased quickly. Chlorogenic acid contentreduced first then increased during the curing. Rutin content increased first and then reduced like aV and the ripe tobacco leaves changed earlier than mature and over mature.Free amino acid content in fresh tobacco leaves reduced gradually with the increase ofmaturity. After curing, free amino acid content increased significantly in mature and ripe tobaccoleaves while reduced in over-mature leaves. Most free amino acid content increased first thenreduced at48℃, like a inverted v in mature leaves and reduced or increased gradually in ripeleaves, and changed much more complex in over mature leaves.(3) The effect of picked-leaf maturity on ultrastructura of tobacco leaf cells was studied and itshowed that picked-leaf maturity had a significant effect on ultrastructura of tobacco leaf cells.When the curing temperature was38℃, chloroplasts and mitochondria content in mature and ripeleaves began reduced and chloroplasts, mitochondria and nuclei began degraded. The damage ofcellular structure was aggravated at later yellowing stage with the increase of maturity. Thecellular structure, shape and material within cells in tobacco leaves of different maturity hadchanged significantly over the yellowing stage.(4) The flue-curd tobacco quality of different maturity was analyzed. The change rule of lossratio of dry material and fresh weight/dry weight ratio in tobacco leaves of different maturity wasmature＜ripe＜over mature and the test of significance was different. There was variability ofthe physical characteristics of flue-cured tobacco of different maturity, the tension and tensilestrength was max in ripe tobacco leaves, thickness and stalk proportion reduced gradually with theincreasing of maturity.Picked-leaf maturity had a significant effect on chemical composition of tobacco leaveswhich showed that, with the increasing of maturity, starch, total sugar and chlorine content increased gradually while protein content reduced, and there were significant difference among allthree treatments in different maturity, reducing sugar content in mature leaves had a significantdifference with in ripe and over mature leaves, nicotine and total nitrogen in mature leaves had asignificant difference with in over mature leaves, potassium content in different maturity showed aV-shaped change, and had a significant difference among three maturities, SUR/NIT and totalsugar/reducing sugar ratio was higher in ripe leaves, nitrogen/nicotine ratio and K/CL reducedwith the increase of maturity, the difference between mature and ripe was less.With the influence of maturity, neutral aroma components differed considerably and itshowed that products degraded by carotene was highest in ripe flue-curd tobacco leaves, high inmature leaves and low in over mature leaves, the solanone content in mature leaves was lowerthan that in ripe and over mature leaves, the products of aromatic amino acid metabolism andMallard reaction increased first then reduced, the change rule of neophytadiene content indifferent maturity of tobacco leaves was mature and ripe＞over mature.