lis 



♦ KNOWLEDGE ♦ 



[April 13, 1883. 



THE CHEMISTRY OF COOKERY. 



VII. 

 By W. Mattieu Williams. 



A SHEEP or an ox, a fowl or a rabbit, is made up, like 

 ourselves, of organic structures and blood, the organs 

 continually wasting as they work, and being renewed by 

 tlie blood ; or, otherwi.se described, the component mole- 

 cules of those organs are continually dying of old age as 

 their work is done, and replaced by new-born successors 

 generated by the blood. 



These molecules are, for the most part, cellular, each cell 

 living a little life of its own, generated with a definite 

 individuality, doing its own life-work, then shrivelling 

 in decay, dying in the midst of vital surround- 

 ings, suffering cremation, and thereby contributing 

 to the animal heat necessary for the life of its 

 successors, and even giving up a portion of its sub- 

 stance to supply them with absorption-food. The cell 

 walls are mainly composed of gelatine, or the substance 

 which produces gelatine, as already explained, while the 

 contents of the cell are albuminous matter or fat, or the 

 special constituents of the particular organ it composes. A 

 description of all these constituents would carry me too far 

 into details. I must, therefore, only refer to those which 

 constitute the bulk of animal food, and which are altered in 

 the process of cooking. 



In the lean of meat, i.e., the muscles of the animal, we 

 have the albuminous juices already described, the gelatinous 

 membranes, sheaths, and walls of the muscular fibre, and 

 the fibre itself. This is composed of muscular Jibrin, or 

 sijntonin, as Lehmann has named it. Living blood consists 

 of a complex liquid, in which are suspended a multitude of 

 minute cells, some red, others colourless. When the blood is 

 removed and dies, it clots or partially solidifies, and is found to 

 contain a network of extremely fine fibre, to which the name 

 of fibrin is applied. A similar change takes place in the 

 substance of the muscle after death. It stiffens, and this 

 stiflening, or rigor nwrtis, is effected by the formation of a 

 clot analogous to the coagulation of the blood, and the sub- 

 stance of this clot (myosin) is so nearly like the fibrin of 

 the blood and the material of the muscular fibre (syntonin) 

 that for our purpose they may be all described as varieties 

 of fibrin. 



The properties of fibrin, so far as cookery is concerned, 

 place it between albumen and gelatine ; it is coagulable 

 like albumen, and soluble like gelatine, but in a minor 

 degree. Like gelatine, it is tasteless and non-nutritious 

 alone. This has been proved by feeding animals on lean 

 meat, which has been cut up and subjected to the action of 

 cold water, which dissolves out the albumen and other 

 juices of the flesh, and leaves only the muscular fibre and 

 its envelopes. The same is the case with the spontaneously 

 coagulated fibrin of the blood ; it is, when washed, a 

 yellowish opaque fibrous mass, without smell or taste, 

 insoluble in cold water, alcohol, or ether, but imperfectly 

 soluble if digested for a considerable time in hot water. 



The following is the chemical composition of these three 

 constituents of lean meat, according to Muller : — 



Alt.um.™. Gelatine. Fibrin. 



Carbon 53 5 5040 527 



Hydrogen 70 664 69 



Nitrogen 155 18-34 154 



Oxygen 220 24 02 235 



Sulphur 1-6 ... 1-2 



Phosphorus ... 0-4 ... O'S 



1000 10000 1000 



There are two other constituents of lean meat which are 



very different from either of these — viz., Kreatine and 

 Kreadnine, otherwise spelled creatine and creatinine. 

 These exist in the juice of the flesh, and are freely soluble 

 in cold or hot water, from which solution they may be crys- 

 tallised by evaporating the solvent, just as we may 

 crystallise common salt, alum, ikc. They thus have a 

 resemblance to mineral substances, and still more so to 

 some of the active constituents of j)lants, such as the alka- 

 loids, </(«i/i«, and crifffdne, upon which depend the stimulating 

 or "refreshing" properties of U'a and coffee. 



Their chemical composition and general relations have 

 suggested the theory that they are the dead matter of 

 muscle, the first and second products of the combustion 

 which accompanies muscular work, urea being the final 

 product. According to this, their relation to the muscle is 

 exactly the opposite of that of the albuminous juice, this 

 being probably the material from which the muscle is built 

 up or renewed. The following is their composition, ac- 

 cording to Liebig's analyses : — 



Kreatine. Kreatinine. 



Carbon 3664 4248 



Hydrogen 6-87 619 



Nitrogen 3206 3717 



Oxygen 24-4.1 1416 



100-00 IWOO 



The juices of lean flesh also contain a little lactic acid — ■ 

 the acid of milk — but this does not appear to be an abso- 

 lutely essential constituent. Besides these there are mineral 

 salts of considerable nutritive importance, though small in 

 quantity. These, with the kreatine and kreatinine, are the 

 chief constituents of beef-tea properly so called, and will 

 be further treated -when I come to that preparation. At 

 present it is sufficient to keep in view the fact that these 

 juices are essential to complete the nutritive value of 

 animal food. 



I may now venture -to state my own view of a somewhat 

 obscure subject — viz., the difference between the roasting 

 or grilling and the stewing of meat. It appears to me 

 that, with the exception of the superficial "browning," it con- 

 sists simply in the difference between the cooking media; that 

 a grilled steak or chop, or a roasted joint is meat that has 

 been stewed in its own juices instead of stewed in water ; 

 that in both cases the changes taking place in the solid 

 parts of the meat are the same in kind, provided always 

 that the roasting or grilling is properly performed. The 

 albumen is coagulated in all cases, and the gelatinous and 

 fibrous tissues are softened by being heated in a liquid 

 solvent. I shall presently apply this definition in dis- 

 tinguishing between good and bad cookery. 



In the roasted or grilled meat the juices are retained in 

 the meat (with the exception of that which escapes as 

 gravy on the dish), while in stewing the juices go more or 

 less completely into the water, and the loosening of the 

 fibres and solution of the gelatine and fibrin may be carried 

 further, inasmuch as a larger quantity of solvent is used. 



Roasting and grilling may be regarded as our national 

 methods of flesh cookery, and ste\\-ing in water that of our 

 continental neighbours. The difference between the flavour 

 of English roast beef and French bouilli or Italian mama 

 is due to the retention or the removal of the saline and 

 highly-flavoured soluble materials. (Concentrated kreatine 

 and kreatinine are pungently sapid.) The Frenchman takes 

 them out of his bouilli, or boiled meat, and transfers them 

 to his bouillon, or soup, which with him is an essential 

 element of a meal If he ate his meat without soup he 

 would be like the dogs fed on gelatine by the bone soup 

 commissioners. To the Englishman, with his roast or 

 grilled meat, soup is merely a luxury, not a necessary 

 element of complete dietary. 



