94 THE GUJ/rrRJ': OF TOIIACCO. 



The starch hugely changes tn sugar, and tlie sugar fi.i'uied is 

 largely cnusuuied in the curing process ; the remainder of lioth of 

 these products is usually destroyed in the fermentation. 



As soon as the sugar is largely cijnsumed the enzynins attack the 

 pr'otein contents of the plant cells, and these continue to Ije destroyed 

 to a certain extent throughout ruling and feiinentation. With 

 the decomposition of the ]_)Voteiii theie is a formation of "amido' 

 compounds. 



During the fermentation there is a loss ..f nitrates. ;i deerea.se in 

 the nicotine contents, and also in the amount of tannin. A thoroughly 

 sweated toliacco contains but a trace of tannin and thus the bitterness, 

 due to its presence in half-sweated tobacco, is removed. 



There is also a disappearance of a jjortion of the fat (-(.ntents. A 

 large amount of fat, <>r of protein, will create products during 

 combustion that will lie destructive of the finer artJina, and one of the 

 benefits of fermentation is that it largely does away with those 

 compounds. 



Thereisalsoadecrea.se of the resin and gums in fei'inentation. 

 In fact, one of the methods of determining how far the fermentation 

 has proceeded is to feel the leaf and note the presence or absence of 

 gum. The resins and gums seem to bear a close relation to the aroma. 

 It is proliable that they are sjjlit uji into (.ther products that are 

 aromatic. It may also Ije that the produets arising from the 

 decompi.witioii of nicotine have a largi' pjart in the ]iroductioii of 

 aroma. The aroma of a eigar does not ap|)ear to be based on the 

 presence of a large anifiunt of nicotine in the eigar, in fact. a. cigai' 

 rich in nicotine may be poor in aroma; the an ana does, however, 

 seem to lie in some way related to the amount of nicotine that was in 

 the tobacco and that has disappeared in the prijcess of fermentation. 

 Nicotianine has lieen supposed to have something to do with the aroma : 

 but this product, which ma}" be formed from nicotine in the sweat, 

 does not appear in all tobaccos, .some of which are ri( h in .'irom.a. 



It has recently been shown that during the proeess of smoking, an 

 ethereal oil is formed from ceitain products of the sweat, and that to 

 this oil is due a portion of the fla\our of tobacco smoke. 



C'itiic, malic and oxalic acids aie pjresent in the cured leaf, l.iut 

 not in as large quantities as in the green leaf. The citric and malic 

 acids may be jjartially transformed in the fermentation to acetic and 

 butyric acids ; this is particularly true of I'erique tobacco ^\•hicll is 

 cured in its own juice. These acids certainly have something to do 

 with the aroma. The piesence of the malic salts is siipposed to make 

 the leaves more .soft and plialjle and to give life a]ul ela.sticitv. This 

 is due to the hygroscopic action of these salts. Stored under similar 

 conditions, leaves rich in malic salts may contain three ]iei' cent, more 

 water than leaves poor in those salts. 



Cured or fermented tobacco is said to have " grain "; this grain is a 

 product of the oxidation in the sweat, and some inanufacturer.s" consider 

 the presence of a well-developed grain as an evidence of good tobacco. 

 It is at lea.st an evidence that the toliacco has lieen thoroughl\ ( ured. 

 This grain is due to the formation of cry.stals of calcium oxalate. 



During the curing and fermentation proi'csses there often appears 

 on the leaf an efflorescence called liy tobacco men ".saltpetre," or In 

 some "light mould." This is due to the presem-e of )iota,ssi)un, sodiun'i, 

 magnesia, calcium and nicotine .salts. These salts may be pri'seut in 

 the leaf in excess and .are forced to the surface in the yao.-ess c^f curing 



