History of Soy Fiber and Dietary Fiber (1621-2013)
William Shurtleff, Akiko AoyagiISBN: 978-1-928914-56-3
Publication Date: 2013 June 7
Number of References in Bibliography: 2004
Earliest Reference: 1621
What is soy fiber?
There are three basic types of soy fiber, one very old, and the other two quite new: Okara (soymilk pulp, the oldest), soy bran (ground soybean hulls/seed coats), and soy cotyledon/isolate fiber.
Okara: In the process of making soymilk or tofu, the liquid milk is separated by filtration from the insoluble fiber. This nutritious by-product (the isoluble fiber) is called okara (its Japanese name) or soy pulp, and has been used for centuries as a source of food, feed, and organic fertilizer.
Soy bran: Soybean hulls, a by-product of the process of crushing soybeans to make oil and meal, can be ground to a light-colored, high-fiber flour generally known as "soy bran."
Soy cotyledon fiber (also called soy isolate fiber): In the process of isolating the protein from defatted soybeans to make isolated soy protein (also called soy protein isolate), the fiber is removed by filtration. It differs from okara in five ways: (1) It does not contain soybean hulls; (2) It has been defatted and thus is lower in fat; (3) It has been treated during processing with mild alkali; (4) It has a much finer texture than okara; and (5) It is almost always sold in dry form, whereas okara is rarely dried.
All three of these products are high-quality, inexpensive sources of dietary fiber. This book emphasizes their food uses, and contains all known publications on their nutritional and medicinal value.
The forgotten nutrient: This book also contains extensive information, including the most important publications starting in the mid-1970s, on the importance of dietary fiber in human diets. During the first half of the 20th century, with a few notable exceptions, dietary fiber was the "forgotten nutrient" (also called the “disregarded Cinderella nutrient”) until physicians working in East Africa noticed that Africans who moved from the countryside into the cities, replacing their traditional high-fiber low-fat diets with European-style diets, quickly became afflicted with a host of European-style diseases. The many studies that have tested their "fiber hypothesis" have shown that dietary fiber is a very important part of a balanced, healthful diet, and that it can offer major benefits in helping to prevent and reverse many serious Western diseases.
How is most okara used? We estimate that more than 95% of all okara worldwide is used as feed for livestock – especially hogs and dairy cows. Most of the rest is used as a natural fertilizer, fairly rich in nitrogen. A small amount is used in cookery.
Where is okara most widely used in cookery? In Japan. It is not uncommon to find recipes that call for okara, and/or a glossary entry, in Japanese cookbooks. However one almost never finds such recipes, or even glossary entries, in Chinese, Korean, Indonesian, or other Asian cookbooks where soyfoods have long been part of the culture.
Insoluble fiber: About 95% of the fiber in okara is insoluble and 5% is soluble (Cho et al. 1997). Insoluble sources of fiber, such as wheat bran, cellulose and okara, are effective in the prevention and treatment of constipation, but must be consumed in moderation.
Okara’s long road to English. Few other soyfoods have had such a long and difficult time finding a standard name in English. Four others that have faced the same problem are fermented black soybeans, natto, yuba, and green vegetable soybeans/edamame. Since okara was first mentioned in an English-language document (a dictionary) in 1867, it has been called by more than 95 different names. These are listed at the end of this introduction – mainly to help those interested in searching.
Brief chronology of soy fiber and dietary fiber.
1621 – In the Qunfang Pu [The assembly of perfumes, or Monographs on cultivated plants], Wang Xiangjin, of China, after discussing tofu, remarks that the residue (zhi, Jap: okara) from the tofu can be used to feed pigs. In times of famine, people also eat this residue.
1692 – The Haikai, Zôdanshû [Comic / unorthodox, collections of various topics] is the earliest known Japanese work to mention okara, which it calls kirazu (meaning “cannot be cut”).
1772 – The word “okara” is first used in Japan in the Gakutaiko.
The Japanese, in line with their ancient tradition of honoring even the simplest and most humble of foods, place the honorific prefix o before the word kara, which means "shell, hull, or husk." Thus o-kara means "honorable shell."
1847 – The word “unohana” is first used in Japan to mean okara in the Honzô kômoku keimô. “Unohana” also refers to a small white flower (Deutzia scabra) that grows in thick clusters on briar bushes and blooms in the spring.
1867 – Okara is first mentioned in English by Hepburn in A Japanese and English Dictionary. Under Kiradz [Kiradzu, Kirazu] he writes: “The refuse left in making tôfu.”
1869 – Okara is first mentioned in French in Fabrication du fromage de pois en Chine et au Japon [Production of tofu in China and Japan], by Paul Champion and M. Lhôte. They refer to it as la pulpe égouttée (the drained pulp).
1874 – Okara is first mentioned in German by H. Ritter in “Tofu, Yuba, Ame,” an article published in Mittheilungen der Deutschen Gesellschaft fuer Natur- und Voelkerkunde Ostasiens (Yokohama) 1(5):3-5. July. They refer to it as Der Pressrueckstand (the pressed residue).
1903 Jan. – Dr. John Harvey Kellogg writes an editorial titled “Constipation” in his periodical Good Health (Battle Creek, Michigan). A Seventh-day Adventist and vegetarian, he is a pioneer in emphasizing the importance of roughage / bulk / dietary fiber in the human diet. He writes: “It is necessary that the food should have a certain bulk in order that intestinal activity may be normally stimulated. Fruits, wholemeal bread” and vegetables “are highly conducive to intestinal activity.”
1917 – In his book Colon Hygiene (417 p.) Dr. J.H. Kellogg states (p. 11-12): "Forty years' experience and observation in dealing with chronic invalids, and careful study of the results of the modern X-ray investigations of the colon, together with observations made at the operating table in many hundreds of cases, has convinced the writer –
"1. That constipation with its consequences is the result of the unnatural habits in relation to diet and colon hygiene which prevail among civilized people."
This is the earliest document seen that links constipation and human diets in civilized countries.
1919 Aug. – William G. Bowers, in “Some studies on the nutritive value of the soy bean in the human diet,” coins the term “soy bran” to refer to soybean hulls (North Dakota Agricultural Experiment Station, Special Bulletin, Food Department).
1920s – McCance and Lawrence are instrumental in developing the concept of unavailable carbohydrate; this was a stepping stone to the modern concept of dietary fiber – plant substances not digested by human digestive enzymes.
1958 – Central Soya Co. of Fort Wayne, Indiana, launches Soybean Flakes, made by steaming soybean hulls then running them through flaking rolls.
1972 – Poly-Soy, a soy cotyledon/soy isolate fiber, is launched by Ralston Purina Co. of St. Louis. Missouri. “Poly” is an abbreviation of “polysaccharides.” This is the first product of its kind.
1973-1974 – Prior to the early 1970s, most of the soy fiber used in human diets was okara, and it was used mostly in East Asia. The rise of the modern interest in key role of dietary fiber in the prevention of disease dates from the years 1973 and 1974, when Denis P. Burkitt, a British physician who had done extensive research on traditional diets in Africa, began to argue convincingly, based on studies of traditional diets, that the lack of fiber in modern Western diets was a major cause of disease. Foods of animal origin (such as meat, eggs. and dairy foods) contain no fiber, whereas most foods of plant origin (and especially those from grains, legumes, and vegetables) are excellent sources of fiber.
1974 Oct. – The terms “soy pulp” and "soypulp,” which refer to okara, first appear in the very creative booklet “Yay Soybeans! How You Can Eat Better and for Less and Help Feed the World,” by The Farm in Summertown, Tennessee. This is also the earliest document seen that that uses the word “soysage” to refer to a meatless sausage-like food in which soy pulp (okara) is the major ingredient. It also contains recipes for Soysage and Soyola (soy pulp granola).
1975 Dec. – The Book of Tofu (and its companion, Tofu & Soymilk Production, 1979), by Shurtleff and Aoyagi, are largely responsible for the word “okara” becoming widely used in English.
This book contains an entire chapter about okara with the most information about okara and the most okara recipes of any book published in English to date.
Before publication of this book, okara was very difficult to obtain in the West, except directly from Asian tofu shops. Soon, however, people started making their own tofu at home (often using tofu kits) and many new tofu shops sprang up and became sources of fresh okara.
1980 – A growing body of medical research, especially that published since 1980, has demonstrated that fiber plays a host of valuable roles in human diets: it aids bowel function (decreasing mouth to cecum transit time, increasing fecal bulk and moisture), lipid metabolism (lowering serum cholesterol), and diabetic control (reducing hypoglycemic rebound in normal individuals, improving glucose tolerance in obese diabetics).
In 1962 there were only 10 scientific papers about fiber; in 1980 there were 500.
By the late 1980s Americans were being advised by dietitians to consume 20-35 grams of fiber daily. In fact, eating more fiber had almost become a dietary fad.
1986 – Fibrim, a soy cotyledon/isolate fiber, is launched by Ralston Purina Co. (renamed Protein Technologies International in July 1987) of St. Louis. Missouri – accompanied by extensive scientific data and a strong marketing program. Fibrim played a leading role helping to document the importance of dietary fiber, and to create new markets from which all soy fiber products could greatly benefit.
1986 – Gene A. Spiller, in CRC Handbook of Dietary Fiber in Human Nutrition, coins the term “Soybean isolate fiber (p. 71, 445) to refer to the fiber resulting from the manufacture of soy protein isolates.
1990 – Grace Lo, in “Physiological effects and physico-chemical properties of soy cotyledon fiber,” a conference paper, coins the term “soy cotyledon fiber” (see Furuda and Brine 1990, p. 49-66).
Alphabetical list of names for okara
(useful for searching digital / electronic text)
bean curd dregs
bean curd lees
bean curd refuse or bean-curd refuse
bean curd residue
bean pulp or bean-pulp
byproduct / by-product of fresh tofu making
byproduct of making tofu
byproduct of tofu making
doufu zha or dou-fu-zha
douzha, dou zha
ground soybean hulls
lees of bean curd
mash or mash residue
mash residue from tofu
meal left over after the extraction of the milk-white fluid
mush, or mush left over
mush left over after straining tofu
okara or o-kara
pi-ch’i or piji
refuse after making Tofu
refuse from manufacture of bean-curd
refuse from the manufacture of bean cakes
refuse left in making tôfu
refuse of bean curd
refuse of beans from making tofu
residue from manufacture of vegetable milk
residue from the boiled and filtered beans
residue of bean cake
residue used for hog feed
soy bean cake
soy bean curd leftovers
soybean pulp or soy bean pulp
soy-bean residue remaining from the preparation of tofu
soya pulp or soypulp
solid waste material
soy bean curd leftovers
soybean curd waste
soybean milk refuse
soy bran (ground soybean hulls)
soy cotyledon fiber
soy isolate fiber
soymilk residue or soy milk residue
soy protein isolate fiber
soy press cake or soy presscake
soy pulp or soy-pulp
Soyresidue or soy residue
Tôfu, and the residue in its manufacture
tokara (tofu with the okara still in it)
tou fu cha
tofu lees or tofu-lees
unohana or u-no-hana
vegetable milk residue
waste bean curd