« 이전계속 »
then tinned in two-pound cans with the addition to each can of two ounces of canning jelly of the following composition:
After sterilizing, the cans were opened and the contents subjected to analysis. The data obtained are as follows:
Composition of Parboiling Water. The liquor, after parboiling the above sample, weighed 280 pounds and had the following composition:
The above data show that the general effect of parboiling upon the canned meat is to diminish its content of water. Only a small quantity of the soluble proteids is found in the liquor, and the other principal constituents removed, aside from water, are the meat bases and mineral content or ash. The fat in the soup liquor was not determined because it rises to the surface and is not in any sense a constituent of the liquor itself. Considerable quantities of fat were removed in parboiling, the amount depending largely upon the temperature. At a low temperature of parboiling, such as described, the amount of fat secured is far less than when the temperature of parboiling is higher.
'TABLE SHOWING THE COMPARATIVE EFFECT OF PARBOILING AND STERILIZING UPON THE FRESH BEEF.
Preparation of Canned Beef with More Intensive Parboiling. In another experiment, determining the effect of the changes produced upon the fresh meat, more vigorous preparatory operations were performed. Samples were secured from eight healthy carcasses for use in this determination. Half of the sample was reduced to sausage and secured for analysis as described, and the other submitted to parboiling, sterilizing, and analysis.
COMPOSITION OF THE SAMPLE OF FRESH MEAT.
1.12 ..10.68 1.13 .24
The original sample represented over a thousand pounds. The opposite sides of the carcasses were prepared for canning and produced the following amount of articles as sold on the market:
The above data show that only about one-third of the whole carcass is suitable for canning purposes. The best and juiciest pieces, it is noticed, are cut away and sold for other purposes. In explanation of the above data it should be stated that only the fore-quarters of the carcass were used and not the whole
In the preparation of the sample for analysis, the same selection was made as for canning, and only the canning meat was used in the preparation of the sample.
Parboiling. The parboiling of this sample was accomplished in the following manner: The meat was first placed in cold water, 50 degrees F., and heated by means of injected steam. In five minutes the temperature had reached 122 degrees F., and at the end of eleven minutes the boiling temperature
was reached and continued for one hour. The soup liquor resulting from the parboiling weighed 1,500 pounds and had the following composition:
These data show that, as in the other cases, the chief extraction from the meat during parboiling is water and the next most important removal is of meat bases and mineral matter or ash. After sterilization in the usual way the cans were opened and the canned beef subjected to analysis. The composition of the canned beef was as follows:
Composition of the Fresh and Canned Meat.-Below is found a table similar to that already given for the other sample, showing the composition of fresh beef and the resulting canned beef.
From the above table it is seen that the shrinkage during parboiling amounts to 46.49 percent of the weight of the fresh meat. Of this shrinkage 82.85 percent is water, 14.11 percent is fat, 1.51 percent ash, and 0.82 percent meat bases. It is noticed that more than half of the water originally found in the meat is extracted by parboiling.
It seems rather anomalous that boiling a substance with water would extract water from it, but in the case of meats it is seen that half the water, or even more, which a meat contains is extracted from it by boiling in water.
The two samples given are extreme cases in the method of preparing meats for canning. In the first instance the meat is placed at once into hot water just below the boiling point and kept there for only a short time. In the second case the meat is placed in cold water and is brought to the boiling point and maintained there for one hour. In the last case the low temperature of the water in which the meat was originally placed favors the extraction of a portion of the soluble protein matter, namely, albumins, globulins, etc., while, on the other hand, the long-continued boiling to which it was subjected tends to decompose the connective tissues of the meat and causes the loss of small particles of the insoluble protein thus separated by disintegration. Although in the last case the shrinkage was much greater than in the preceding experiment, practically no insoluble protein matter was extracted, mechanically or otherwise.
Canning of Beef without Parboiling.-To determine the amount of shrinkage which takes place and the general effect which is produced by canning meats without parboiling, samples were prepared, sterilized, and canned in the usual way, with the exception of the omission of parboiling. On opening the cans it was found in each case that the meat had shrunk to about twothirds of its former volume and that the place was occupied by a liquid containing a number of particles of solid matter. The appearance of the sample was much less inviting than that of meat canned after parboiling.
An analysis of the sample was made, with the following results: Total weight of sample, 31 ounces; weight of canned meat, 21 ounces.
CANNING OF BEEF WITHOUT PARBOILING.
Protein and gelatin,.
Composition of Liquid.-The liquid in the can was examined with the following result: Weight of liquor, 10 ounces.
The above data show that the beef lost 32.06 percent of its weight in the canning, a little over half of which is water.
It appears that less protein matter is extracted when the meat is parboiled by being plunged into boiling water than when it is packed in a can without parboiling and subsequently subjected to the temperature of sterilization. In the former case the soluble proteins in meat near the surface are coagulated before they can diffuse into the surrounding water. In the other case, owing to the
low conductivity of meat, the temperature at the surface of the can penetrates slowly to the interior and the juices which are extracted from the meat carry with them protein matter in solution which is afterwards precipitated by heat and remains in the liquid as matter coagulated at the temperature of sterilization.
It is seen that parboiling has many advantages. It extracts less of the valuable matter from the meat, it shrinks the meat before packing so that the tins contain more nutrient matter, and it improves the appearance of the meat to the consumer when opened.
Relation of Canned to Fresh Meat.-In the following table is given the number of ounces of canned meat in a number of cans compared with the equivalent amount of fresh beef used in filling them:
It thus appears that a can of 26.9 ounces of beef contains, as an average content, an amount of meat equivalent to 42.1 ounces of fresh beef, and retains practically all of the nutrient value of the larger quantity of fresh beef.
Canned Ham and Bacon.-It seems unnecessary, as a rule, to can ham and bacon properly cured and transported in a suitable manner. There are occasions justifying the use of these products in tropical countries and in other places far remote from the sources of manufacture, and where the preservation of them, by reason of the character of the climate, is difficult.
The proper preparation of these articles, packing in tins and sterilizing, makes it possible to send them to the most distant points and to have them consumed in the most unfavorable climatic conditions. Canned ham, as it is found upon the market, has a higher percentage of fat and a consequently lower percentage of protein than canned beef. The ham is packed closely and the smaller pieces added for the purpose of filling up interstices between the larger pieces of meat and keeping the can full. It is reasonable to infer that. the added meat is pork, although very probably it may not always be so.
Composition of Canned Ham and Bacon.-The character of the canned ham and bacon upon the market may be illustrated by the composition of the following samples (these samples were purchased in the open market and are presumably representative of the products as commonly sold in the shops):