80 The N.Z. Journal of Science and Technology. [April 
skinned, and then canned. The cans are then processed in the ordinary 
manner. 
The question of spoilage has already been dealt with by the author in 
a recent article in this Journal* and will not be discussed again here. 
The following results have been obtained on analyses of various canned 
meats :— 
Table II. 
— 
Canned Roast 
ri. and 
Boiled Beef. 
Canned 
Corned Beef. 
Canned 
Tongues. 
Per Cent. 
Per Cent. 
Per Cent. 
Water 
58-89 
56"35 
55-17 
Fat 
13-99 
11-43 
20-23 
Proteids insoluble in water 
19-25 
22-37 
15-64 
Soluble proteids, including gelatinoids . . 
3-59 
2-02 
1-33 
Meat bases . . 
1-58 
1-11 
1-23 
Saltpetre 
, , 
0-09 
0-08 
Salt 
0-53 
3-37 
2-90 
Other mineral salts .. 
0-75 
1-23 
0-73 
'o 
Meat-extracts. (2, 7, 9, 16, 17.) 
Commercial meat-extracts are manufactured from the finely chopped 
muscular tissues of flesh, such as lean meat, heart-muscle, or diaphragms. 
The meat is placed in tanks containing cold water, steam is admitted, 
and the material is boiled for about half an hour. 
The liquor obtained from meat which is parboiled in the process of. 
preparing certain canned meats is also utilized. 
The liquors while hot are pumped into a large tank and there settled 
in order to separate out in part the particles of meat-fibre which are present. 
The supernatant liquor is then filtered through cloth filter-bags to further 
remove any fine solids still in suspension. The fat present is skimmed off, 
and the clean liquid is then concentrated in steam-heated pans, either 
under vacuum or at ordinary atmospheric pressure. The partially con¬ 
centrated liquor is finally transferred to a finishing-pan and heated until 
the water content approximates 20 per cent, and the material is of a 
syrupy consistency. , 
Constant stirring during the final stages of evaporation is essential to 
secure uniformity in regard to consistency and composition of the finished 
product. 
It appears necessary to carry out the finishing or final stages of the 
concentration of the extract in the ordinary atmosphere, for apparently 
certain oxidation compounds are produced at this stage which add to the 
palatability of meat-extract, and these compounds are not formed under 
vacuum. Apparently a process similar to caramelization takes place. 
The whole process has to be watched carefully because of the liability 
of certain nitrogenous compounds to be formed which give a somewhat 
bitter flavour to the extract. The nature of these compounds has been 
determined, and they belong to a class of substances similar to the pep¬ 
tones. The peptone-like bodies are not found in the original liquor from 
which the extract is manufactured, but are found in varying amounts in 
the finished extract, having been formed probably during the process of 
concentration by the action of the normal flesh acids and salts upon the 
* Bacteriology in Relation to Commercial Meat Products, vol. 3, 1920, pp. 209-13. 
