上部煙葉帶莖烘烤中主要化學(xué)成分變化
Major Chemical Component Changes in Upper Tobacco Leaves with Stalk during Flue-curing
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摘要: 研究了烘烤過程中上部葉采收帶莖與不帶莖煙葉主要化學(xué)成分變化規(guī)律,。結(jié)果表明,，（1）烘烤期間帶莖煙葉的總水分表現(xiàn)為前期下降緩慢后期下降較快，束縛水則緩慢地散失,，自由水的失水高峰早于總水分,，在24～48 h內(nèi)，自由水含量有所增加,，帶莖煙葉的失水速度明顯低于不帶莖煙葉,，表明此段時間帶莖烘烤下莖桿中的自由水分向葉片內(nèi)發(fā)生了運移。（2）烘烤期間帶莖煙葉淀粉含量低于不帶莖煙葉,，烤后則稍有下降,；可溶性總糖和還原糖的含量在72 h前增加幅度較大，之后有所降低，烤后兩者都低于不帶莖煙葉,。（3）烘烤期間帶莖煙葉總氮變化不大,，硝酸鹽和亞硝酸含量表現(xiàn)為前期上升后期下降的規(guī)律，烤后硝酸鹽含量稍有降低,，亞硝酸鹽含量則稍有升高,，鉀含量也稍有增加。Abstract: The changes of major chemical components of DJ (Treatment 1, upper leaves harvested and cured with stalk) and WJ (Treatment 2, upper leaves harvested and cured without stalk) during flue-curing were studied. The results showed that: (1) the loss rate of total water in tobacco leaves with stalk was slow in the first 48 hours and then increased sharply, while the bound water decreased gradually with the proceeding of curing. The peak of free water loss came earlier than the total water. The free water increased a little from 24 to 48 hours. The ratio of total water loss in DJ was evidently lower than that in WJ between 24h and 72h, which showed that the transport of free water from stalk to leaf. (2) The content of starch in DJ was lower than that in WJ during the process, and decreased in cured leaves. The total sugar and reducing sugar in DJ increased quickly during the first 72 hours, and then decreased, whereas lower than those in WJ. (3) Little change occurred in the total nitrogen of DJ during the process, and the contents of nitrate and nitrite increased quickly in the first 72 hours followed by rapid decrease afterwards. The content of nitrate exhibited a slight decline, whereas the nitrite and potassium increased slightly.
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