Lard is a major edible animal oil and is produced in most countries of the world. It is rendered from selected fatty tissues of hogs, usually by the process known as wet rendering- that is, heating with steam in open or closed tanks. The lard produced by this method is known as prime steam lard and is very mild in flavor and light in color.
Substantial amounts of lard are also produced by the dry-rendering process, which involves indirect heating in the absence of water in horizontal drums, provided with rotating arms for agitation. In federally inspected packing houses in the United States, the yield of lard and rendered pork fat is between 31 and 34 pounds per animal, or about 14 per cent of the live weight of the hog.
So-called rendered pork fat is a special grade established by the United States Department of Agriculture, and is obtained by the same processes as lard, but the raw material may include lower grades of the animal tissue. Although an edible product, it usually has a slightly darker color and a characteristic flavor. In some respects, its stability against oxidation and other aging processes is better than that of lard.
The principal lard-producing countries are the United States, West Germany, Brazil, France, Italy, Yugoslavia, the Netherlands, Spain, Mexico, and Canada. United States production represented about a quarter of the total world production in the 1960's. The United States was also one of the major exporting countries, accounting for a large percentage of the world trade in lard; it exported as much as 668 million pounds in 1963, a recent peak year. The chief destinations for the exports were countries in Latin America and Europe.
The major uses of lard are in cooking and as a shortening material in bakery products. In these uses it is competitive with many vegetable oils, such as soybean and cottonseed oil, both of which, however, must be hardened (hydrogenated) to produce products comparable to lard. In recent years, new refining methods and special chemical treatments have greatly improved lard for shortening purposes. One of these treatments involves a chemical rearrangement of the triglyceride structure which produces a shortening having improved properties for use in baking. Another useful product is created from lard by chilling and separating the higher-melting-point stearine from the softer component, known as lard oil. The latter is used as a lubricant in textile manufacture and in steam engines and other machines, as, for example, thread-cutting machines employed in metalworking.
Tallows and Greases
Both edible and inedible grades of tallow are derived from the carcass fat of beef and dairy cattle. The recovery processes are similar to those by which lard is rendered. Edible grades of beef tallow are de-rived from selected portions of the animal. However, the inedible grades represent the major portion of the total tallow produced.
The term "tallow" refers to the harder or higher-melting-point fats, which are chiefly derived from cattle offal, whereas the term "grease" is usually applied to the softer fats such as are obtained from hog fat tissues. Commercial grades, generally having a darker color, may also be derived as byproducts from the manufacture of animal glue, from butcher shop scrap fats, and from garbage and other sources. Although tallows and greases are produced in practically every country of the world, the major producing countries are the United States, Argentina, Australia, Great Britain, France, Canada, and New Zealand. Production in the United States accounts for nearly one half of the world total and exports from that country averaged about a million tons a year in the 1960's. The great majority of the markets for exports of inedible tallows from the United States are the European countries and Japan.
Like lard, edible tallows are used in shortening blends, where their higher melting points are desirable in producing a firm product. Inedible grades of tallows and greases are principallv used
in the manufacture of soap. It is estimated that almost 70 per cent of the world production is directed to this end use. Most of the bar toilet soaps on the market contain 75 to 80 per cent of .tallow soap, and virtually all of the industrial soaps used in power laundries have a tallow soap base.
A new and expanding use for tallows and greases has developed in recent years, namely, as an additive in small percentages (2 to 10 per cent) to mixed animal feeds, including poultry and cattle food. The rapid increase in such usage of tallows and greases in the United States will undoubtedly continue and should be duplicated in other countries all over the world. An additional major use is in the production of fatty acids, which involves hydrolyzing the tallow or grease into free fatty acids and glycerol. After being separated, the two components are distilled under high-vacuum conditions to produce the pure end products.
The major source of world production of butter is cow's milk, although in some countries, such as India, goat and buffalo milk are also used in the production of a butter known as ghee. In the United States the bulk of the production consists of so-called "creamery butter," that is, butter produced in factories that specialize in its manufacture. The commercial product is about 81 per cent fat, lj/£ to 3 per cent salt, 1 per cent curd (casein), and 15 to 17 pen cent water.
After the cream has been separated from the milk, it is pasteurized to destroy the bulk of the natural bacterial organisms. Special cultures of bacteria are then added, which develop a pleasing flavor and aroma under controlled temperature conditions. The conditioned cream is then churned in rotary power churns and washed to remove the buttermilk. The final step is the addition of coloring matter and a small amount of salt for flavoring and for keeping properties.
The principal use of butter is for food. It is employed mainly as a table spread, but also in cooking, baking, and candy manufacture. Recent Department of Agriculture statistics show that consumption of butter in the United States declined due to increased usage of margarine. For instance, in 1935-1939 the per capita consumption of butter was 17 pounds, and in 1966 only 5.8 pounds. During this period, consumption of butter substitutes in the form of margarine rose from 2.9 pounds to 10.7 pounds per capita. The year 1957 was the first in which the per capita consumption of margarine in the United States exceeded that of butter.