Table of contents
Okara or soy pulp is a by-product of soy milk or tofu production from soy beans (Glycine max (L.) Merr., organic?). The soy pomace (raw?) has a neutral taste and is a good binding agent for soups and sauces as well as a vegan egg substitute.
Culinary uses of okara
What is okara? Soy pulp is the pressed pulp of soy bean, i.e., soy puree (soy bean pulp or soy mash). It is pureed and squeezed soy beans. Okara is left over from the production of soy milk (or tofu) as a pressing residue (in the filter or as a sediment) and is considered waste in many parts of the world, although it is suitable for human consumption and contains valuable nutrients.
Soy pulp should only be consumed when cooked, because, being a soybean product, it is toxic in its raw state. In the case of soy pulp of industrial origin, process-related heating can be assumed (duration and temperature depending on the production method1,27) - home-made soy pomace is mostly raw. In any case, please heat the soy pulp before consumption (see below under 'Own preparation').
Since the soy pulp has no taste of its own, it can be used in many different ways in the kitchen. It can be used as a vegan addition to muesli, in granola, in sauces, soups and spreads of all kinds, and dried as crumbs for breading mushrooms or vegetables. Vegetable patties, okara balls, croquettes and gnocchi with soybean pulp are also delicious. Baked goods such as bread, biscuits or muffins are also made from okara. Pastries with okara are very moist. Okara polenta (e.g., with chopped tomatoes and spices) or ravioli fillings (e.g., with pumpkin) can also be found in various recipes available online.
There are many traditional recipes with soy pomace in China, Korea, and Japan. In South Korea, okara (kongbiji) is used in a stew with pork and kimchi (kongbiji-jjigae) or in soups. Chinese cuisine refers to soy pulp as dòuzhā2. Recipes for okara pancakes (e.g., with shallots) and soup with okara fillings are popular in Chinese cuisine. In Japan, a salad of okara is eaten with vegetables, tuna or ham and mayonnaise and stirred into ice cream.3 Fried soy pulp with soy sauce, vegetables, shallots and shiitake mushrooms - or unohana - is a popular side dish there.
How can you use okara as egg substitute? Okara can serve as a substitute for eggs or for flour (binding agent). As an egg substitute or egg replacement, soybean pulp can be used in various cakes that do not require yeast to rise. The ratio here is: 1 egg = 1 tbsp fresh okara + 2 tbsp water.4,5 You can use dried and ground okara as a flour substitute, but this gluten-free variant cannot be baked on its own, so the okara flour is best mixed with other flours. At Hermann's Eatery in Berlin they are experimenting with a mixture of 40% chickpea flour, 30% rice flour, 20% okara flour and tapioca (as glue).6
How to make okara
Make your own okara in five steps: Soy milk can be made by soaking dried soybeans in water and pureeing them. Suitable organic soybeans can be found in supermarkets, Asian shops and health food stores. The following five steps lead to the production of raw soy pomace and even further processable (raw) soy milk:
1) Soak 1 cup of dried soybeans (about 180 grams) in a bowl of water overnight. Since the soybeans increase in volume as they soak, the water should cover the beans generously.
2) After the swelling process, pour the beans through a sieve and rinse generously with running water. Next add more water for further processing in a ratio of 3:1 (water: soaked beans).
3) Blend 1 cup soaked soybeans with 1 cup water until the ingredient has a creamy consistency (1½-3 minutes depending on the power of the blender). Gradually add the remaining water, whisking constantly. (The less water you use, the more concentrated the soy milk is.)
4) Pour the pureed product over a linen or sieve cloth placed in a suitable sieve over a collection container. Alternatively, you can stretch the cloth and attach it to the container. Hand pressure can be applied to the contents of the cloth, which will result in soy milk spillage.
5) Squeeze hard to separate soy milk from solid. The "pomace" in this case is okara.
You can dry the okara further to extend its shelf life, or freeze it fresh. For more steps to process the raw soymilk, see our ingredients: soymilk, unflavored, unfortified, or flavored soymilk.
Just like soybeans, raw okara must be cooked before consumption, otherwise it is toxic. In various proven recipes, the authors give cooking times of around 20 minutes. Another option is to bake on a baking sheet at 150°C (302°F), between 15 and 20 minutes; this serves to preserve okara crumbs (or flour) and can be stored for several weeks. A scientific study has found an 80% reduction in certain nutrient-limiting compounds in soybeans, which are the basis of okara, when cooked for 20 minutes.29 Based on this information, we recommend cooking for no more than 20 minutes with exposure to higher heat.
Vegan recipe for Okara Hummus
Ingredients: For a creamy hummus, use around 230-240 g (cooked, not raw) organic okara (1¾ cup5,7), 60 ml lemon juice (¼ cup8), 55 g tahini (or tahini, sesame butter, sesame paste, ¼ cup7), 2 roughly chopped garlic cloves, 1 tsp cumin, ¾ tsp (or less) salt and 3-5 tbsp water.
Procedure: Put all the ingredients in a blender with 3 tablespoons of water and puree everything until you get a smooth mass. If the hummus is too thick, add more water. Pepper or paprika are suitable for seasoning, and sesame seeds for decoration. This goes well with raw vegetable sticks, for example.
Or try our recipe for a vegan okara radish pan with white cabbage.
The former Olympic chef and author Bruno Wüthrich in his cookbook Alles Okara, published in 2019, illustrates how soy pomace can enrich the daily menu and prevent food waste.9
To find vegan recipes with okara follow the reference: "Recipes that have the most of this ingredient".
Not only vegans and vegetarians should read this: A Vegan Diet Can Be Unhealthy. Nutrition Mistakes. |
Purchasing - storage
Okara is mainly known in Asian countries and is therefore not so easily available in some other parts of the world. Okara may not be available with major supermarkets or farmers’ markets either.
Where can you buy okara? Okara may be found - fresh or dried (as okara powder) - in online shops, in Asian grocery stores and in well-stocked health food stores. It is recommended that you give preference to organic products when buying.
Many producers of soy milk or tofu add soy pulp to compost or have it processed into animal feed or biogas. It may be possible to save part of the soy pulp from being thrown away by directly expressing interest to the producer.
The production of tofu from black soybeans results in greyish soy pulp; but we couldn't find any sources for it.
Storage tips
Fresh soybean pulp spoils very quickly due to the high water content. It can be stored in the fridge in an airtight container for up to a week. When dried as crumbs, it will keep for several weeks.10 Fresh okara can be frozen for up to three months.
Ingredients - nutritional values - calories
Cooked soybean pulp is low in carbohydrates and contains 7 % protein, and about 80 % water.11 The high fiber content, which is considered an advantage, probably refers to dried okara: the USDA (U.S. Department of Agriculture) does not provide detailed information on the contents in fresh okara. In any case, in its dried form (as okara powder or flour) it appears to contain four times the amount of fiber compared to whole wheat flour.12
Baked goods infused with fresh soy pulp or okara flour13 are lower in calories and higher in fiber than traditional baked goods (okara is 76 kcal/100g11) and may therefore contribute to weight loss. Scientific studies have shown that soy pomace suppresses weight gain and increases plasma lipid in mice14 - and that this effect is probably also observed in humans.15 Similar results were obtained with soybean.16
According to Wikipedia, the quality of soy or okara protein can be compared to that of animal protein. Soybeans aren't the only plant food with a complete amino acid profile, meaning that they contain all eight essential amino acids, but they have plenty of them. Black beans also have all eight essential amino acids, but have about half the quantity. There are other plant foods also with all eight essential amino acids. Soybeans are the only vegetable that contains all eight essential amino acids.17,18
The nutritional value profile of okara contain the amino acids threonine (0.13 g/100g) and lysine (0.21 g/100g), which cover 14 % and 11 % of the daily requirement respectively. Threonine and lysine are irreversibly transaminated and are the only two amino acids that are truly essential.19
Transamination
Transamination is the shifting of the α-amino group of an amino acid to an α-keto acid. A new amino acid and a new α-keto acid are formed. In this way, an organism can produce or break down non-essential amino acids itself.
Amino acids are the building blocks of proteins. Since an organism cannot produce essential amino acids on its own, it has to ingest them with food. The following amino acids are considered essential for humans: isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. Strictly speaking, only the corresponding C skeletons of the keto acids are essential for six of them, since these can be transaminated. (Biesalski, Nutritional medicine: According to the curriculum of nutritional medicine of the German Medical Association. 3rd edition 2004: p.92-93). This does not apply to threonine and lysine because these are irreversibly transaminated and can no longer be changed.
Lysine is important for the maintenance of muscle and connective tissue, and threonine plays an important role in growthing and uric acid metabolism. It is also an important building block of antibodies. Compared to whole legumes and seeds, soybean pulp is rather low in threonine (spirulina 3 g, soybean 1.8 g, lupine 1.3 g and unpeeled hemp seed 1.3 g). Similar ratios also apply to lysine, because okara only has 3.5 g/100 g of proteins, even though it is a soy product. This is due to the high water content of the soy pulp (> 80 %).
Likewise, soy pomace contains significantly less iron and starch than whole soybeans. The vitamin content of the soybean pulp is also significantly less.
Soy pulp is gluten-free and therefore suitable as a food for people with gluten sensitivity or celiac disease (gluten-sensitive or gluten-induced enteropathy).
Since okara is a soybean product, it contains antinutrients: trypsin inhibitors, saponins, and hard-to-digest lectins. This largely overrides the cooking process. You can read more about this under the ingredient soybean, ripe seeds, raw.
You can find the total ingredients of okara, the coverage of the daily requirement and comparison values with other ingredients in our nutrient tables. In the article Nutrients explained you will get a detailed insight into the topic.
Health effects
The consumption of soy and soy products is associated with a lower incidence of vascular diseases and cancer, especially breast cancer (soy contains phytoestrogens). However, the research data are conflicting.20 Kristen Montgomery, assistant professor at the College of Nursing at the University of South Carolina in Columbia, South Carolina, emphasizes the positive effect on vasomotor tone and arterial walls in cholesterol patients. She also recommends better control of body weight and cholesterol levels to lower diabetes and cancer risk (breast and prostate cancer).21
Soy pulp is said to have the following positive properties: As mentioned above, experiments on mice have shown that it counteracts obesity and increase in plasma lipids. In addition, a preventive effect against fatty liver (steatosis) was shown.14,22
Fermentation of okara using certain bacteria makes it easier to digest and increases the availability and absorption of the nutrients in the body.27 Fermented products are said to lower cholesterol and have antioxidant properties.23,24
Dangers - intolerances - side effects
Raw okara (e.g., from your own soy milk production) has to be heated before it is consumed. Like the soybeans themselves, the pomace from them is toxic when uncooked
The food industry is increasingly turning to soy and many milk substitute products for allergy sufferers and celiac patients now contain soy. Intolerances are not uncommon, but real allergies are. Cross-reactions with peas, peanuts and other legumes as well as with birch pollen allergy are possible.25
Always read the ingredient information for bread, buns or hamburgers: these may contain small amounts of soy flour or okara.
Genetically modified soy is grown in the United States. So, look out for GMO-free soybean pulp.
Use as a medicinal plant
Soy lecithin (soy extract) is used in medicine for minor lipid metabolism disorders, especially hypercholesterolemia.26
Traditional medicine - naturopathy
Thanks to the isoflavonoids, soy extract is said to counteract menopausal symptoms, improve liver metabolism and help lower blood lipid levels.
Ecological footprint - animal welfare
The increasing demand for soy and soy products for the animal feed industry over the past 50 years has led to large-scale deforestation, especially in South America, to make room for monocultures.32 In addition to the long transport routes of soy from these cultivation countries, changes in land use also play a major role the ecological footprint. This is because the conversion of rainforests to arable land, especially when it is burned, releases the carbon stored in the trees which enters the atmosphere in the form of CO2.33 Since okara is a product of soy processing, it can be assumed that water consumption and CO2 emissions correspond roughly to that of tofu or soy milk.
Okara is a waste product. Ideally, this nutrient-rich food is used in the best possible way for human consumption (as described under "Culinary use") in order to counteract the waste of resources. In reality, 50% of the okara produced in the form of soy flour or soy press cake is used as animal feed in intensive animal fattening (to produce meat and eggs), and the rest ends up as waste.34 Correct disposal plays a major role here. However, in Asian countries such as Indonesia, okara is often disposed of directly into the wastewater without further treatment. This can have a negative impact on the environment due to the high nutrient content. There are now initiatives to use okara as an energy source in the form of biogas.35,36
Worldwide occurrence - cultivation
Okara is a traditional part of Japanese, Korean and Chinese cuisine. It has also been appreciated in the West since the 20th century.
Possibility of confusion
Okara pulp differs from tofu in the following ways: Okara is technically a by-product of soy milk production. Soy milk is made from the basic ingredients: soybeans and water. The soybean pulp, or pomace that remains after the soymilk and has been pressed and filtered or skimmed, is called okara. Tofu, on the other hand, is obtained by coagulating the protein components in the soy milk. Depending on how this soy quark is processed, you get different types of tofu.
Okara soy pulp is different from the okra fruit. Okara comes from the pulp of the mature seeds of the soybean plant (Glycine max (L.) Merr.), while the green capsule or pod of the okra plant (Abelmoschus esculentus) is known as okra.
Additional information
Okara (approx. 1.1-1.2 kg per kg of soybeans13,27) and soy whey are by-products of tofu production. As described, soy pomace remains after pressing out the soy milk (from soaked soy beans) and soy whey after coagulation (from soy milk) to soy quark. Many soymilk producers dispose the soy pulp because the high-fiber solid spoils very quickly due to the high humidity. This is a waste of food that has been criticized from an ecological, ethical and economic point of view.
According to a report from 2016, scientists from the Food Science & Management (FSM) department at the School of Agricultural, Forest and Food Sciences (HAFL) are investigating how raw materials such as soybean pulp could be used more efficiently and be better integrated into human nutrition (for resource efficiency30). They are examining the direct application in baked goods and vegan dairy substitutes. This requires more knowledge about physical, hydrothermal, enzymatic and fermentative treatment steps,30 which supports the conclusion of the following scientific abstract: “The low solubility of okara protein makes it difficult to incorporate into many food systems. Okara protein hydrolysates with improved solubility and other functional properties could serve as a low-cost protein ingredient in processed foods (functional foods).31
Soy pulp is thought to be the oldest of three types of soy fiber (alongside soy bran and soy protein isolate).
Tempeh is obtained by fermentation with the fungus Rhizopus microsporus var. oligosporus, and red Onkom is obtained with Neurospora.
Alternate names
Okara is sometimes also referred to as soy pulp, soy pomace, soy bean pulp, soy porridge or soy (press) cake (usually related to the feed). However, soy pulp is also known as biji, kongbiji, dòuzhā, dòufuzhā etc. The term 'soy egg protein' is incorrect.
In English, Okara means soy pulp, soybean residue, tofu lee(s) or tofu dregs. A tofu-dreg-project or okara project in China means a poorly built building or government project that is in danger of collapsing.
Other applications
Okara is often used on farms as animal feed23 for pigs, chickens and dairy cows, especially near soymilk or tofu factories.
In addition to being used as animal feed, soy pulp is also used in industry as a fertilizer. It is spread over the fields and used as nitrogen fertilizer. For this reason, it is also good to use as compost since it can contribute organic nutrients and nitrogen.
Soy pulp is also used as feed for silkworms and is used in the production of ceramics.23
In China, soy porridge is used for beauty care. Mixed with homemade almond milk, the soy pulp makes a pleasant face mask.
Bibliography - 35 Sources
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