Filtering okara from a fresh batch of homemade soymilk.
|Chinese||豆渣 / 豆腐渣|
|Kanji||雪花菜 / 御殻|
|Hangul||비지 / 콩비지|
Okara, soy pulp, or tofu dregs is a pulp consisting of insoluble parts of the soybean which remains after pureed soybeans are filtered in the production of soy milk and tofu. It is generally white or yellowish in color. It is part of the traditional cuisines of Japan, Korea, and China, and since the 20th century has also been used in the vegetarian cuisines of Western nations.
Okara is the oldest of three basic types of soy fiber. The other two are soy bran (finely ground soybean hulls), and soy cotyledon/isolate fiber (the fiber that remains after making isolated soy protein, also called "soy protein isolate").
Okara that is firmly packed consists of 3.5 to 4.0% protein, 76 to 80% moisture and 20 to 24% of solids.[which?] When moisture free, the gritty okara contains 8 to 15% fats, 12 to 14.5% crude fiber and 24% protein, and contains 17% of the protein from the source soybeans. It also contains potassium, calcium, niacin.:151:168 Most of the soybean isoflavones are left in okara, as well as vitamin B and the fat-soluble nutritional factors, which include soy lecithin, linoleic acid, linolenic acid, phytosterols, tocopherol, and vitamin D. Okara contains some antinutritional factors: trypsin inhibitors (mostly destroyed by cooking), saponins, and hemagglutinin, which cannot be easily digested. Fermentation (by proper species of bacteria) of okara is not only conducive to digestion and absorption of okara nutrients, but also further improves the nutritional value. It can eliminate the bean’s sense of smell, increase the amount of edible fiber, free amino acids, sugars, fatty acids, vitamin B12, vitamin B2, and flavoprotein.
Most okara worldwide is used as feed for livestock - especially hogs and dairy cows. Most of the rest is used as a natural fertilizer or compost, which is fairly rich in nitrogen. A small amount is used in cookery.:3–4
While relatively flavourless when eaten on its own, it can be used in stews such as the Korean biji-jjigae or in porridges. It's also used as an addition to baked goods such as breads, cookies and muffins, and can serve to create a crumbly texture in these foods.:168
Okara can be used to make tempeh, by fermenting with the fungus Rhizopus oligosporus,:168 using a tempeh starter, or to make presscake tempehs that use ingredients such as brown rice, bulgur wheat, soybeans and other legume and grain combinations.
The product is sometimes used as an ingredient in vegetarian burger patties. Additional uses include processing into a granola product, as an ingredient in soysage and as an ingredient in pâtés.:168
In pet food
The product is also used as an ingredient in pet foods.:168
As fertilizer or compost
When not considered foodstuff, it may be deemed soybean curd residue (SCR). Some 800,000 tons of soybean curd residue is disposed annually as tofu production byproducts, just in Japan. As mass waste, it is a potential environmental problem because it is highly susceptible to putrefaction. The protein in SCR is of better quality than from other soy products; for example, the protein efficiency ratio of SCR is 2.71 compared with 2.11 for soymilk, but the ratio of essential amino acids to total amino acids is similar to tofu and soymilk. Nevertheless, it remains a challenge to current processes to commercially extract the proteins and nutrients from SCR waste.
- David B. Haytowitz and Ruth H. Matthews for the USDA Human Nutrition Information Service December 1986 Agriculture Handbook No. 8-16. Composition of Foods: Lugumes and Legume Products.
- Applewhite, Thomas H. (editor) (1989). Proceedings of the World Congress on Vegetable Protein Utilization in Human Food and Animal Foodstuffs. The American Oil Chemists Society. ISBN 093531525X
- Soy20/20. Spring 2005 Okara: Overview of Current Utilization
- Shurtleff, William; Aoyagi, Akiko (1979). Tofu & Soymilk Production. Volume 2: The Book of Tofu. ISBN 1928914047
- Li, Shuhong; Zhu, Dan; Li, Kejuan; Yang, Yingnan; Lei, Zhongfang; Zhang, Zhenya (8 September 2013). "Soybean Curd Residue: Composition, Utilization, and Related Limiting Factors". ISRN Industrial Engineering. 2013: 1–8. doi:10.1155/2013/423590.
- Claire Lee for the Star (Malaysia) 24 December 2013 Revisiting the mystique of Silla in Gyeongju
- Robbie Seinnerton for Japan Times. 20 October 2002 The garden of heavenly tofu delights
- (staff editors) (September–October 1977). "How We Make and Eat Tempeh Down on The Farm". Mother Earth News. p. 4. Retrieved March 11, 2013.
- Shurtleff, William; Aoyagi, Akiko (1979) The Book of Tempeh. Soyinfo Center. p. 114. ISBN 0060140097
- KeShun Liu. "Oriental Soyfoods". Chapter 6 in Asian Foods: Science and Technology, eds. Catharina Y.W. Ang, et al. CRC Press (April 5, 1999) ISBN 978-1566767361
|Wikimedia Commons has media related to Okara.|