History of Soybean Fiber Products: Okara (Soy Pulp) and Soy Bran (Ground Hulls)
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A Chapter from the Unpublished Manuscript, History of Soybeans and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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Okara or soy pulp is the insoluble carbohydrate residue that is left over after the production of soymilk or tofu. Soy bran is finely pulverized dry soybean hulls.
HISTORY OF OKARA (SOY PULP)
Etymology . Okara (pronounced oh-KAR-uh) is a Japanese word, and the general or generic term for the product. The Japanese, in line with their ancient tradition of honoring even the simplest and most humble of foods, form this word by placing the honorific prefix o before the word kara , which means "shell, hull, or husk." Thus o-kara means "the honorable shell." A more old-fashioned term for okara is kirazu , which means "that which cannot be cut;" tofu, by contrast, can be cut. When the Japanese refer to okara as an ingredient in cooking, they often call it unohana after Deutzia scabra , a tiny white flour that grows in thick clusters on briar bushes and blossoms in the spring. This reflects okara's potentially light, almost fluffy nature, like grated coconut. A final name, not widely used, is tofu kasu ("tofu residue"). Thus this one substance can have many names, depending on the usage or context.
In Chinese, okara is most widely known (in pinyin ) as douzha ("soy lees"), which is a condensation of another less widely used term doufu zha ("tofu lees"). It is also called doufu zha-tsu ("child of tofu lees").
In Indonesian, the widely used okara is called ampas tahu ("tofu residue"). In Filipino it is sapal , in Korean it is piji , in Thai it is tau-hu tor , and in Vietnamese it is ??
Okara has been called by remarkably large number of names in English, perhaps because there is no food or substance exactly like it but many somewhat like it. It has been known variously as "tofu cakes" (Kellner 1889), "tofu cake or kara" (Oshima 1905), "the residue from soymilk" (Morse 1918a, Jordan 1918), "kirazu or tofu residue" (Miller 1933), "the residue left from making soymilk" (Van Gundy 1936), "bean pulp or mash" (Whiteman and Keyt 1938), "the ground soybean pulp or mash left over after making soy milk" (Morse and Cartter 1952), "the residue pulp" (Chen 1956), and "the pulp or residue" (Who??). Loma Linda Foods calls the product "soy fines." In 1974 The Farm introduced the term "soy pulp" and used it consistently in their many subsequent publications on soyfoods. In 1975 Shurtleff and Aoyagi introduced the Japanese term okara in their Book of Tofu . After several years of discussion on the merits of the terms "okara" and "soy pulp" the soyfoods industry in America ended up using both interchangeably, but tended to prefer the shorter Japanese term in preference to its easier-to-remember English counterpart. It was felt that "okara" was more neutral and inviting when used to describe foods, since terms like "pulp" and "residue" do not have appealing culinary connotations. Would you rather have an Okara Burger or a Soy Pulp Burger?
In Europe after 1975, the term "okara" came to be widely used. It was das okara in German, le okara in French.
HISTORY OF OKARA IN EAST ASIA
Since the time of the earliest production of tofu or soymilk, the great majority of all okara in East Asia has always been used as livestock fodder, with a portion being used as an organic fertilizer. But some has always been used as food, with usage increasing in times of famine or food shortages.
China . Many Chinese tofu makers set up a small hog farm next to their tofu shop and use okara as their main source of hog fodder. Sauteed okara can also serve as a poor man's side dish with rice. It is also inoculated with Actinomucor elegans mold spores, and incubated for 10-15 days to make cakes of the fermented food meitauza (Translate?? Chinese term?? Shih 1937; see also Chapter 39).
Japan . Since early times okara has been the basis of a number of popular dishes, widely served in homes, and at restaurants and delicatessens. The most popular of these is Unohana-iri , made by sauteing okara with diced vegetables, then simmering the mixture in a sweetened shoyu broth. For other okara recipes, see The Book of Tofu (Shurtleff and Aoyagi 1975).
In 1899 Kano and Iishima of the Tokyo Army Medical College did the first investigations on okara and human nutrition, finding that 79% of the protein was digestible. These results were first published in English by Oshima in 1905.
Indonesia . A very large proportion of the okara produced in Indonesia is used as food, particularly in the form of two very popular fermented foods: okara tempeh (cakes of okara fermented with Rhizopus mold spores) and okara onchom (similar but orange-colored cakes fermented with Neurospora intermedia mold spores). Recently Indonesian government nutritionists have developed an inexpensive high-protein food, okara-fish-rice, containing 75% dried okara.
HISTORY OF OKARA IN THE WEST
Europe . The earliest known reference to okara by A Westerner was by German Kellner in 1889. In his 2-page "Tofu Cakes," he gave its composition on a wet and dry basis, and discussed its use as a fodder and fertilizer. Prinsen Geerligs (1895, 1896) gave the nutritional composition of okara on a dry-weight basis. Bloch (1907) and Li Yu-ying and Grandvoinnet (1912) also reported on the nutritional composition, and found that it contained no starch. Li was the first to discuss its used as food, stating that okara could be dried and ground to form a food for human beings. Since he made soymilk and tofu in Paris, he may in fact have sold his okara for use as food. The Lancet in England (1915) noted in an article on soymilk that okara had already been used for making a bread. Rouest (1921) recommended feeding both soymilk and the remaining okara to animals. The new breed of tofu shops that opened throughout Europe in the late 1970s used okara in many of the ways described for their US counterparts below.
United States . The earliest known reference to okara in the US was by the Japanese researcher Oshima in 1905. He cited that 79% of the protein was digestible, recommended its use as a food, and stated that in Japan poor people used it as an ingredient in miso soups. Jordan (1918) stated that okara made "an excellent base for muffins and even bread, when used in the proportion of one part to three or four parts of wheat flour." In 1929 T.A. Van Gundy in southern California made the first known commercial okara-based product in the US. Called Soy Spread, it came in a can and contained okara, salt, mace, and other seasonings. It had a soft consistency and was said to taste and smell like potted chicken. In 1931 Morse, of the USDA, mentioned that okara could be used in various Western-style recipes including rarebit (Welsh rabbit; melted cheese poured over toast or crackers), stuffed green peppers, gingerbread, macaroons, and chocolate fudge. He also noted that it could be ground to make a flour. In 1932 Madison Foods began making and marketing a "steaklike meat analog" called Vigorost, made from wheat gluten and okara (or tofu), plus peanut meal and seasonings. Containing 19.4% protein, it was used for entrees, sandwiches, and salads. In 1938 Whiteman and Keyt of the USDA published a recipe for Okara Macaroons. Also in 1938 Willis Miller made and marketed an okara spread in New York. In 1939 Dr. Harry W. Miller used the okara from his Soya-lac soymilk to make three popular ready-to-eat products: Soya Loaf, a seasoned mixture of okara and gluten; Soya Spread, seasoned okara; and Veja Links, the world's first meatless wiener, made of seasoned okara and wheat gluten, packed in a sausage casing. If the product had been made 40 years later it might have been called "Soysage." In 1942 Mildred Lager wrote that there were a number of okara sandwich spreads on the market in southern California. These were probably made by Van Gundy's La Sierra Industries and by Loma Linda Foods.
The first studies of okara in its relationship to tofu making were published in 1960 by Smith, Watanabe, and Nash. They did extensive okara recovery studies for many varieties of US soybeans, finding that, on average, about 29% of the original soybeans on a dry weight basis were recovered in the okara. Roughly 18% of the original protein was lost/recovered in the okara. The first modern nutritional studies on okara were done by Hackler and co-workers (1963, 1967). They found that okara contained the highest quality protein as measured by PER (Protein Efficiency Ratio) of all soybean fractions tested. Values compared with milk protein (2.86) were: okara 2.71, dehulled soybeans 2.51, tofu 2.20, soymilk 2.11, and whey 1.93.
The first mention of okara used in tempeh production in a Western publication was in 1964 in KO Swan Djien's "Tempe, a Fermented Food From Soybeans," in which he mentioned that in Indonesia okara was sometimes mixed with soybeans in making tempeh in order to lower the price.
The Farm in Tennessee played an important role in creating American-style okara recipes and popularizing the use of okara in the US. In early 1972 they began to make soymilk on The Farm. Shortly thereafter they began to experiment with using the okara to make tempeh and other recipes. In 1974 they published a 14-page booklet containing a description of okara (they called it "soy pulp") and six American-style recipes. Soy Pulp Burgers, Scalloped Potatoes and Pulp, Soysage, Protein Spice Cake, Soy Pulp Cookies, and Soyola (Soy Pulp Granola). The granola and cookie recipes appeared in their Farm Vegetarian Cookbook (1975). Additional recipes for Soy Pulp Tempeh and Soysage Dogs were given in the 1978 revised edition of the vegetarian cookbook.
The Book of Tofu by Shurtleff and Aoyagi (1975) had an entire chapter about okara, introducing the word, and giving a nutritional analysis plus the first cultural and historical information about it, the first published recipe for homemade okara tempeh, and the largest collection to date of okara recipes (8 Japanese and 22 Western style). The latter included Okara Burgers, Okara Muffins and Pancakes, Okara Granola, Okara Sponge Cake, Okara Doughnuts, and Okara Peanut Butter Cookies. Additional information on okara and okara tempeh appeared in their Tofu & Soymilk Production (1979), The Book of Tempeh (1979), and Tempeh Production (1980).
Three new concepts in the late 1970s combined to generate new interest in okara: the importance of fiber in a healthful and balanced diet, the value of not wasting and recycling and the interest in vegetarian diets and meat substitutes. The fact that many people were making their own tofu and that many new tofu shops had more than they could use, made it available for experimentation. A number of tofu shops published small flyers or booklets about okara, with recipes and nutritional information. Martha Wagner helped popularize the use of okara by writing "Okara: The Little-Known Superfood" ( New Age magazine, 1980) and "Cooking with Okara" ( Vegetarian Times , April 1982); each gave recipes. Okara began to be used like the newly popular wheat bran.
Since all US tofu shops and soy dairies produced large amounts of okara each day, they had to find a creative way to use it. By far the most popular commercial product was Soysage, made along the lines developed by The Farm; typical ingredients included okara, whole wheat flour, wheat germ, nutritional yeast, soymilk, oil, and 5-10 herbs and spices--a nice alternative to pork sausage! Few people realized, however, that the product had a much earlier origin. Jon Cloud (1981), in doing trademark research for his own product, discovered that
During World War II a product called Soysage was developed and trademarked by W.H. and Alice Baun, owners of Imperial Brands of Chicago, Illinois. Their Soysage (a dry mix for meatless sausages) was made from soy flour, peanut flour, cottonseed flour, wheat middlings, wheat germ, yeast, vegetable protein, and seasoning. Very little is known about that venture, however, since the trademark was renewed for only a short time; after six years of inactivity, the product lapsed into oblivion.
The first commercial okara-based soysage in North America was made by White Wave in 1977 in Boulder, Colorado. At the first soyfoods conference in 1978 they gave a demonstration of how they made and steamed the product in stainless steel tubes. Within a few years soysage was being made by tofu shops all over America. Variations on the basic theme were Soyloaf and Soysage Pate. By 1979 Island Spring was selling their Smoked Soy Loaf in supermarkets in the Seattle area. The same year North Country Soy in Vermont was producing three flavors of soysage (Mild America, Hot German, and Spicy Italian) in 1/2-pound and 7-pound sizes, and even exporting it to Montreal. Sunbow Farm in Oregon published an 8-page booklet, "Tofu, Soy Sausage, and Burger Mix," containing 12 recipes for using their soysage and several recipes for using their Burger Mix, a dried mixture of okara and various seasonings. Also in 1979 The Soysage Cookbook by Maxine Cloud and Joan Burdett was published. It contained 30 vegetarian recipes for using soysage in sandwiches and main dishes, but did not tell people how to make their own soysage. By April 1981 Jon Cloud, owner of Cloud Mountain in Buffalo, New York, made and marketed 2,000 pounds of soysage a month. However when he applied for a US trademark, a Bureau of Trademarks official told him to desist from using the term, as it was misleading. Only after the product was reclassified as a "non-standardized food" could the name be used. A good update on Soysage around the world appeared in the summer 1981 issue of Soyfoods magazine (Cloud 1981; Stunkard 1981; Cain 1981; Leviton 1981).
By 1978, the many soy delis connected with tofu shops also began to use okara to make tasty ready-to-eat foods. For example, The Soy Plant in Ann Arbor, Michigan, developed Okara Carob Bars, Okara Peanut Butter Balls, Okara Granola Balls, and Okara Brown Bread. Tofu Gardens Deli (later Lotus Cafe) in Rochester, New York, created Okara Gingerbread and Okara-Carob Brownies.
In mid-1980 Travids Burgeson, founder of Pacific Tempeh, began studying the possibility of producing okara tempeh, and in February 1983 his company introduced Temeph Lite, America's first commercial product; it contained 25% by weight of brown rice. By February 1983 there were three brands of okara tempeh on the market, made by Pacific Tempeh (CA), Swan Gardens (FL), and Southwest Soyfoods (NM). Okara could also be used as either a low-cost extender in soy tempeh or, much better, as the sole ingredient in delectable mock fish sticks or cutlets made of oakra tempeh.
During the 1970s one large producer of soymilk, Loma Linda Foods, did work on drum-drying okara and selling it to the baking industry for use like bran (to add dietary fiber) and to give protein complementarity, since okara contains about 20% soy protein in a dry-weight basis. To date, however, the project has not found a way to make itself cost effective.
Other new potential nonfood uses of okara include as a fermentration substrate for ethanol or methane production, or an organic fertilizer.
HISTORY OF OKARA IN THE THIRD WORLD
As noted in Chapter 27, since the 1970s, there has been a major increase in soymilk production in many Third World countries. Starting in the late 1970s, many of these producers began to develop food uses for okara. In Brazil, cassava flour was fortified with 40% okara (the by-product of VITAL soymilk) and corn flour with 30% okara. Moretti, developer of the "Mechanical Cow" in Brazil, offers an optional okara dryer with each machine. The okara can then be used in breads, tortillas, etc. In Sri Lanka okara has been used in place of shredded coconut in Coconut Sambol (a spicy topping).
HISTORY OF SOY BRAN
In East Asia, since ancient times, soybean hulls, remaining from the production of soymilk, tempeh, yuba, and some soy flour, have been used in mixed livestock fodders. Since they have not been used in foods, they have never been given a special name. The term "soy bran" was coined by the American, Bowers, in 1919, to refer to pulverized soybean hulls intended for food usage. Berczeller next used the term in 1932. It became quite popular in the US during the late 1970s, with the growing interest in dietary fiber and the launching of a commercial soy bran by Archer Daniels Midland Co.
Bowers (1919) found that soy bran, easily separated from whole dry soybeans by milling, comprised roughly 8% of the bean by weight. it consisted of 37% crude fiber, of which 77.1% was digestible. A diet composed solely of well cooked soy bran appeared to have no ill effects, physically or physiologically. Berczeller (1932) developed and patented a steam cooking process to prevent the oxidation of soy bran.
Strong interest in the health value of increasing consumption of dietary fiber, starting in the late 1970s, led to research on soy bran. Forbes (1979) and Weingartner et al. (1979), both at the University of Illinois, found that its inclusion in the diet did not reduce mineral absorption. Munoz and co-workers (1978, 1979) found that of all the basic sources of dietary fiber tested, soy bran had the most significant effect in lowering blood cholesterol and relieving constipation. In 1979 Archer Daniels Midland Co. put the world's first commercial soy bran on the market in the US. It was used like wheat bran, mostly in baked goods?? In 1980 soy bran, mixed with wheat bran, was being added to biscuits in England.