History of Soy Oil Shortening Page 1

by William Shurtleff and Akiko Aoyagi

A Chapter from the Unpublished Manuscript, History of Soybeans and
Soyfoods, 1100 B.C. to the 1980s

©Copyright 2004 Soyfoods Center, Lafayette, California


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Webster's Dictionary defines "shortening" as "an edible fat used to shorten baked goods." The verb "to shorten" is defined as "to add fat to (pastry dough) in order to make tender and flaky." According to these definitions, "shortening" refers to a use or function of a fat, so that either lard or a vegetable shortening could serve this function. Moreover, "shortening" is only one of several functions a shortening could serve.

Today the term "shortening" usually refers to a "vegetable shortening," a semisolid fatty food made entirely from refined edible vegetable oils, usually a blend of two or more partially hydrogenated oils. Shortenings are used in cooking and serve four basic functions: (1) to shorten baked goods (especially pastries, pie crusts, and breads) in order to make them tender and flaky. They do this by preventing the cohesion of wheat gluten strands during mixing, thus literally shortening them and making the gluten less elastic and sticky; (2) for frying, since they are hydrogenated to a lower iodine value and have a small percentage of unsaturated fatty acids, they are more resistant to oxidation and rancidification than typical vegetable oils; (3) to add flavor and richness to typical breads, and to extend their shelf life; and (4) for "creaming power" in making icings and fillings; when beaten, often with sugar, they incorporate large volumes of air bubbles and thus produce a fine, delicate structure. Lard does not cream well.

A major difference between shortenings and margarines is that the former generally contain 100% fat, whereas margarines typically contain 20% milk or a similar aqueous phase. Lard, which lacks natural antioxidants, is much less stable and much more resistant to oxidation than an equally unsaturated shortening.

There are various types of shortenings. Those made with only vegetable oils are produced in much greater amounts than those which are a blend of animal and vegetable fats. Most are made by blending 3-5% of a hard fat (typically palm or cottonseed oil fully hydrogenated to an iodine value of roughly 1-8) with a soy oil shortening base, consisting of soy oil hydrogenated to an iodine value of about 75 at roughly 220°C (425°F) and 10 pounds pressure (Erickson et al. 1980). This mixture is then pumped into a small closed system, where the fat is continuously solidified on externally refrigerated cylinders and scraped therefrom. The fluid fat is supercooled to 16-18°C and small crystals form. The supercooled fluid mixture is run into a second worker unit to continue the growth of the small crystals without cooling. The shortening is packed and allowed to temper at about 27°C (80°F) for 1-3 days to give the proper crystal structure (Wolf and Cowan 1975). All-hydrogenated type shortenings, in which the oil is more completely hydrogenated, are used largely in baked goods. Liquid shortenings have been developed more recently for ease of metering and reduced saturated fat content.

Worldwide, shortenings are used most extensively in North America (USA and Canada) and northern Europe, where the Netherlands, W. Germany, the UK, and Sweden have the highest per capita consumption. Unfortunately, we have been unable to find any figures or time series data on world shortening production. In many countries, little or no shortening is used; margarine or liquid oils are preferred. In India an imitation ghee called Vanaspati, a cross between shortening and margarine, is extensively used (as described at Margarine).

Etymology . Shortenings evolved in the late 1800s as lard substitutes. The earliest reference in the Oxford English Dictionary of the verb "to shorten" (meaning to make short or friable) dates from 1733 and refers to soil, not food: "Sand will shorten and crumble the Clay before the Plough." The first food reference to the verb dates from 1883: "The crust being shortened with suet." The earliest reference listed for the noun "shortening" dates from 1823: "Shortening, suet or butter, in cake, crust, or bread." From the mid-1800s until about the 1930s, the term "shortening" was generally used in sentences in the form of "fats used for shortening include lard and tallow," to refer to a function rather than to a specific type of product.

Lard was the favored fat for use as shortening; tallow (the fat rendered from beef or mutton) was considered too firm and too pronounced in flavor. The earliest lard substitutes or adulterated lard products, made by mixing other animal fats or vegetable oils with lard, were called "refined lard," a term that emerged in trade circles in the 1870s. Since the latter term was considered somewhat deceptive, the term "compound lard" began to appear in the trade in the mid-1880s, and in 1888 the two largest producers of such products decided to start labeling them as "lard compounds." From 1906-1930 the official US government terms for these products were "lard compounds and substitutes." The "lard compounds" had to contain over 50% lard, while substitutes could contain less. After 1911, when hydrogenated all-vegetable-oil shortenings were introduced as new foods rather than lard substitutes, the terms "lard compound" and "compound" were dropped and replaced by proprietary names (such as Crisco), which were not suggestive of any animal product. Generically these new products were often called "vegetable compounds." The present term "shortening," used to refer to lard substitutes made largely or entirely from vegetable oils, started to become the standard in the early 1930s. In 1931 the US Department of Commerce's Census of Manufacturers first switched their category title from "Lard substitutes and cooking fats" to "Shortenings other than lard."

The term "shortening" may have been slow to catch on since it is somewhat misleading; shortenings are used for various purposes besides shortening. Throughout this chapter we will use the term "shortening" in the sense defined above. Most shortenings made today are more precisely known as "vegetable shortenings," indicating that they contain no animal products.

Rendering and Pressing Lard and Tallow . In order to understand the early histories of shortening and margarines, it is necessary to understand the processes of rendering and pressing lard and tallow. Rendering is the process of separating fats or oils from animal tissues by heating them in the presence or absence of moisture. Wet rendering is now more widely used, in part because dry rendering imparts a slight cooked flavor. Usually animal fats are rendered within a few hours after the animals are killed for best flavor. The first oil or fat products used by humans were undoubtedly rendered from the carcasses of wild animals. Later lard, the body fat of hogs, came to be the preferred fat for edible purposes in many non-Moslem countries. Lard was generally found to have a better consistency and flavor than beef or mutton tallow (which was too firm) or marine oils (which were too fluid) (Bailey 1951).

Dry rendering is done by heating the fat gently in an open kettle. Before 1840 lard was defined as the relatively hard fats rendered from the kidney and bowels (the leaf) of the pig. (Suet, the hard fat around the kidneys and loins of beef and mutton, yielded tallow.) Leaf lard was often (and today almost always is) dry rendered, both for its distinctive flavor and its greater stability. There are two types of wet rendering: low and high temperature. Traditionally low temperature wet rendering was used. Fat was trimmed from select portions of the animal, then chopped fine and placed in hot water (usually at temperatures below 80°C to give a bland flavor). As the fat is gradually liberated from the cells, it floats to the surface of the water, where it is collected by skimming. The membranous matter (greaves) is separated from the aqueous (gluey) phase by pressing to extract additional fat. The residue is used for animal feed or fertilizer. After 1840, the process of steam rendering was introduced, allowing all the fat on an animal to be used and without being chopped. However it yielded a softer product, which appropriated the term "lard" and came to be known as "whole hog lard." Today most lard is steam rendered in pressurized tanks and called "prime steam lard."

It has long been known that tallow and lard, like most fats, are a mixture or triglycerides (see Chapter 47). The most important of these are stearine (a fairly hard, white solid fat), palmitine (a softer solid), and olein (a liquid). If stearine predominates, as in tallow, the fat is hard; if olein, as in chicken fat, it is soft. Fats such as lard and shortening are both what oil chemists call "plastic fats" or "plastic solids" While appearing to be soft, homogeneous solids, they actually consist of a mass of small crystals in which is enmeshed a considerable portion of liquid oil. Thus there are two phases present, the solid state is finely dispersed, and the two are in a certain proportion so that the plastic solid resists small stresses but flows like a viscous liquid when subject to deforming stresses. Any animal fat can be fractionated (separated) quite easily into its solid and liquid component fats by melting it at a given temperature, then allowing it to cool slowly. The solid fats, stearine and palmitine, will solidify or congeal and settle out. The liquid olein can then be separated by straining and draining it off. Since some of the liquid olein generally adheres to the solid fats, the latter are often pressed to squeeze out more of the liquid fraction and make the separation more complete. This process of fractionation, generally known as "the graining and pressing of fat" was being practiced in Europe (France) by the 1760s.

Tallow is a solid at ordinary temperatures with a melting point of 43-54°C (109-129°F). A choice of edible tallow, rendered with water at temperatures averaging 68°C (155°F), yields what is called "oleo stock" or, in France, premier jus . Upon being melted, chilled, and pressed in a filter cloth, it yields oleo oil (a liquid of melting point 31°C, widely used in early margarines and oil lamps) and oleostearine (a solid of melting point 50-54°C, widely considered a by-product of the manufacture of oleo oil). Better grades of lard, rendered in water at relatively low temperatures (typically 52°C or 126°F), yield what is called "neutral lard," the lard counterpart of "oleo stock." If neutral lard is melted, cooled, and pressed, it yields lard oil and firm lard stearine.


Early Developments . Although shortening is basically an American invention, originating in the 1870s, it traces its roots back to developments in northern Europe several hundred years earlier. An excellent study of the early origins of shortening in both Europe and America is found in The American Vegetable Shortening Industry by Weber and Alsberg (1934), upon which we have drawn heavily.

The traditional fats of northern Europe and early America were butter and lard, both solid or semisolid animal fats. (Lard was traditionally used for shortening only in parts of the world where baked wheat and rye products were consumed.) Whale oil was also used, largely for illumination in lamps. Vegetable oils did not start to be of much importance in these areas until about the 1870s. Thus it was in these areas that we should expect to find the origins of the lard substitute industry. These beginnings were fairly recent since it was not until the mid-1800s that the demand for edible fats such as lard and tallow began to exceed the supply, and serious attempts began to be made to find substitutes.

The major causes of this increasing shortage of fats were the advance of the industrial revolution, the population growth and relative affluence that accompanied it. Throughout the 1700s the industrial revolution created major new demands for fats as lubricants for railroads and industrial machinery, as illuminants in lamps and candles, as an ingredient for soaps (especially to wash the growing supply of cotton goods that replaced woolens), and in foods for a more affluent diet. During the Middle Ages in Europe (AD 500 to 1500) candles had been much more widely used than oil lamps, since harder fats were abundant, oils relatively scarce. The main oils, olive oil in the south, and some rapeseed and linseed oils in the north, were not widely used as food. In the early 1500s whale oil started to become more important and the use of oil in lamps became much more widespread after the invention of the Argand lamp in 1784. To fill this new demand, inventors were spurred to discover new sources of oil.

During the early 1800s the French became the leaders in the new fields of chemistry and technology of oils and fats. In the 1760s the French had developed the process for pressing tallow (described above) to yield a hardfat (oleostearine) and a liquid oil (oleo oil). During the late 1700s the oleostearine started to be used extensively in the production of candles that were better than those made of tallow and less expensive than those made of beeswax or spermaceti (a wax from the head of the sperm whale); the oleo oil started to be used in oil lamps, to take the place of whale oil, which it had largely replaced by the 1840s. During the French revolution and the Napoleonic period, the French, cut off from free access to whale oil by the British blockade of the Continent, were stimulated to make great advances in the field of oil chemistry, and soon they became the world's leaders in oil refining and candle making. They extended their planting of rapeseed and developed new methods for refining the oil for use in lamps. In 1815 winterization of vegetable oil was developed to prevent it from congealing in lamps in cold weather. Bleaching with steam was developed in 1816 and with fuller's earth in the 1820s. Refining with caustic soda and deodorizing were developed in the 1840s.

In the first half of the 19th century there is increasing mention of the growing scarcity of oils and fats in Europe. The advent of meat canning and cold storage of whole carcasses further reduced supplies of fat. The greatest pressure prior to 1860 had been to produce more hard fats for candles and oil for lamps, but by the late 1860s there were increasing pressures to produce substitutes for edible fats as well, especially butter. This led to the development of margarine by Mege Mouris in France in 1869 (as described in the next section). The key ingredient in margarine was oleo oil, pressed from edible tallow. With the growth of the margarine industry, large quantities of edible oleostearine, the by-product of oleo oil production, became available. In Europe, relatively little of this was used in foods; it continued to be used in tallow candles until the early 1920s, when it was gradually replaced by the petroleum-based paraffin-wax candle. But in America it became the basis of an entire new industry, making lard substitutes.

The earliest records of the production of compounded cooking fats on a household scale in Europe date from the first half of the 19th century. They were probably produced at a much earlier date. There was even some commercial production in the mid-1900s, but the first large scale production of lard substitutes and shortenings developed in the United States. There are several reasons that these products never became very popular in Europe until after World War II: (1) Northern Europeans preferred lard; (2) Inexpensive margarine was widely available and came to be used in cooking in many of the ways Americans used shortenings; in Europe both table margarines and cooking or industrial margarines were developed; (3) As early as 1880 there was legal prosecution of lard compounds in England under the Sale of Foods Act. This may have discouraged further experimentation on the Continent as well; (4) Europe did not grow a lot of oilseeds, which were the raw material for shortening; (5) Europeans did not traditionally use lard or shortening in basic breads; Americans did. To help make up its deficit in food oils and fats, Europe started in about 1890 to use relatively saturated vegetable fats, as from coconut and palm oils, which had long been imported for use in the candle and soap industries, as a substitute for animal fats in foods. Europe also imported huge quantities of lard from America, just as in the period following World War II it began to import huge quantities of soybeans from America to process into oil and meal.

Prior to 1940 the main producer of shortening in Europe was the UK, followed by Germany. In 1938 the UK produced 116,000 tonnes (metric tons) of cooking fat (shortening); 70% of the oil used was vegetable oil (especially cottonseed and peanut), and most of the rest was marine oil. The same year Germany produced only 16,000 tonnes, compared with 676,000 tones for the USA (Schwitzer 1956).

1940-1980s. By the 1950s, with low-cost edible oils widely available from the US and lard prices steadily increasing, shortening production in Europe was increasing steadily. UK production in 1953 had risen to 189,563 tonnes, while German shortening production had risen to 51,700 tonnes (vs. 678,000 tonnes in the USA). According to Gander (1976), the leading European countries in terms of per capita consumption of shortenings and compounds were as follows (figures for margarine are given in parentheses for comparison): Netherlands 7.7 kg (13.4 kg), W. Germany 3.3 kg (8.2), UK 2.1 kg (5.0), Sweden 1.1 kg (16.5), and France 0.8 kg (3.2 but 8.6 kg butter). By comparison, USA consumption was 7.8 kg (4.9); it was the only Western country where shortening consumption exceeded margarine.

Unfortunately we have very little information?? about the history and present status of soy oil in European shortenings. When was soy oil first used? When and why did it first start to be widely used? How much is used today and what percentage is this figure of the total? We only know that large amounts were being used by the 1970s and early 1980s.


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