DiFFEKEM Methods of Curing Tobacco. 



The cllemical chang-es are biouglit about by highly complex 

 protein forms called enzymes, the resultant activities of which give 

 changes responsible for the texture, aroma, and colour of tlie finished 

 product. Yet all these changes can easily be stopped by subjecting 

 the tobacco to unfavourable conditions. For instance, if the ripe 

 leaves are quickly dried out with heat they will become worthless, 

 and will not possess any of the properties characteristic of cured 

 tobacco, or should the tobacco leaves be bruised or subjected to 

 extremely cold temperatures, none of these changes will, nor can, 

 take place. Thus the grower must su regulate tlie curing of his 

 tobacco that the leaf must go tbrough a process of gradual starvation. 

 When the leaf is thoroughly ripe, it will have accumulated a certain 

 amount of surplus food and will continue to \i\e until all this food is 

 used up. It is during the starvation period, if the conditions under 

 which this takes place are favourable, that a considerable Cfuantity 

 of the starch so accumulated will he broken \i\) into sugtirs by one 



Variety Plots. 



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type of these enzymes called diastase. The protein-content of the 

 leaf and the nitrates also decrease during the curing of the leaf. The 

 former is accomplished by the proteolytic enzymes, and the latter may 

 be due to the reductases. Another notable change during this period 

 is the disappearance of the green colouring matter, chlorophyll. 



The tobacco leaf when harvested contains from 70 to 80 per cent, 

 of moisture, most of which is lost during the curing. The rate of 

 drying must be so regulated that this moisture is given oft gradually, 

 otherwise the results will not be satisfactory. 



The two chief factors which control the rate of curing in such 

 a way as to change the undesirable properties of the green leaf into 

 the desirable forms so much sought after in the cured leaf, are heat 

 and moisture. It is for this reason, if a suitable building is used for 

 <;uring tobacco where these two factors can he artificially controlled, 

 that such a high percentage of cigarette leaf can be produced. 



