Soy milk

Soy milk
Chinese name
Traditional Chinese	豆漿
Simplified Chinese	豆浆
Literal meaning	bean thick liquid
Transcriptions Standard Mandarin Hanyu Pinyin dòujiāng Wade–Giles tou4-chiang1 IPA [tôʊtɕjáŋ] Wu Romanization [dɤɯ tɕiã] Yue: Cantonese Jyutping dau2 zoeng1
Alternative Chinese name
Chinese	豆奶
Literal meaning	bean milk
Transcriptions Standard Mandarin Hanyu Pinyin dòunǎi Wade–Giles tou4-nai3 IPA [tôʊnàɪ] Yue: Cantonese Jyutping dau2 naai1
Second alternative Chinese name
Chinese	豆花水
Literal meaning	bean flower water
Transcriptions Standard Mandarin Hanyu Pinyin dòuhuāshuǐ Wade–Giles tou4-hua1-shui3 IPA [tôʊxwáʂwèɪ] Yue: Cantonese Jyutping dau2 faa1 seoi2 Southern Min Hokkien POJ tau hoe chúi
Third alternative Chinese name
Traditional Chinese	豆腐漿
Simplified Chinese	豆腐浆
Literal meaning	bean thick liquid
Transcriptions Standard Mandarin Hanyu Pinyin dòufujiāng Wade–Giles tou4-fu-chiang1 IPA [tôʊfutɕjáŋ] Wu Romanization [dɤɯ vʊ tɕiã] Yue: Cantonese Jyutping dau2 fu2 zoeng1
Vietnamese name
Vietnamese alphabet	Sữa đậu nành
Korean name
Hangul	두유
Hanja	豆乳
Japanese name
Kanji	豆乳
Transcriptions Revised Hepburn tōnyū

Soy juice (also called soya milk, soymilk, soybean milk, or soy milk and sometimes referred to as soy drink/beverage) is a beverage made from soybeans. A traditional staple of Asian cuisine, it is a stable emulsion of oil, water, and protein. It is produced by soaking dry soybeans and grinding them with water. Soy juice contains about the same proportion of protein as cow's milk: around 3.5%; also 2% fat, 2.9% carbohydrate, and 5% ash. Soy milk can be made at home with traditional kitchen tools or with a soy milk machine. Despite the terminology used by consumers, it is illegal to sell soy milk under that name in the European Union, where - with certain exceptions - EC Regulation (1898/87) has restricted the term 'milk' to mammary secretions since 1987; in such countries the term 'soy drink' is commonly used.

The coagulated protein from soy juice can be made into tofu, just as dairy milk can be made into cheese.

Origins

The oldest evidence of soy juice production is from China where a kitchen scene proving use of soy juice is incised on a stone slab dated around AD 25–220. It also appeared in a chapter called Four Taboos (Szu-Hui) in the AD 82 book called Lunheng by Wang Chong, possibly the first written record of soy juice. Evidence of soy juice is rare prior to the 20th century and widespread usage before then is unlikely.

According to popular tradition in China, soy juice was developed by Liu An for medicinal purposes, although there is no historical evidence for this legend. This legend first appeared in the 12th century and was not clearly stated until late 15th century in Bencao Gangmu, where the development of tofu was attributed to Liu with no mention of soy milk. Later writers in Asia and the West additionally attributed development of soy juice to Liu An, assuming that he could not have made tofu without making soy juice. This may be incorrect. In addition, some recent writers claim Liu An developed tofu in 164 BC.

History

1365 ca - Yiya Yiyi [Remnant Notions from I Ya], by Han Yi (in China) is the earliest document seen that mentions soymilk, which it calls doufujiang.

1640 ca. - Soymilk is probably in use in China by the beginning of the Qing dynasty (H.T. Huang 2006).

1704 - Soymilk is first mentioned in English by Domingo Fernandez Navarrete in his book A Collection of Voyages and Travels. Navarrete served as a Dominican missionary in China.

1790 ca - An undated painting of hawkers selling soymilk (doujiang) in China, by Yao Wenhan, is from the Qing dynasty

1866 - Soymilk is first discussed as a drink in its own right by the Frenchman Paul Champion, who traveled in China. In a French-language article he stated that the Chinese had taken their cups to tofu shops to get hot soymilk, which they drank for breakfast.

1896 June - Soymilk is first referred to in the United States by Henry Trimble in the American Journal of Pharmacy.

1897 July 7 - The term "soy-bean milk" (or any cognate /relative thereof) first appears in a USDA or U.S. government publication: C.F. Langworthy. 1897. "Soy beans as food for man." USDA Farmers' Bulletin No. 58. p. 20-23. July 7. The table, titled "Comparison of the composition of soy-bean milk and cows' milk," gives the nutritional composition of the two liquids. The same term next appeared in Dec. 1916 in a USDA Bulletin by Piper & Morse, and then on 7 Feb. 1917 in a USDA Weekly News Letter.

Each of these early documents is cited in full and discussed in a detailed history of soymilk and other non-dairy milks which has been published.

Prevalence

Greek Café Frappé prepared with soy juice, topped with additional cinnamon

File:Melon-flavored soy drink.jpg

A packet of Melon-flavored soy drinks.

Use in East Asia:Only in China has soymilk (doujiang) long been used as a beverage. Traditionally it was been served hot, ladled from a caldron for breakfast, at the place where it was made either sweetened or as the base of a salted soup served with deep-fried crullers. It was not used to feed infants or as an infant formula.

Starting in the 1920s, a small number of companies in China started to make and sell bottled soymilk.

In Hong Kong, Vitasoy was launched in 1940 by K.S. Lo as a nutritious food for refugees fleeing during World War II. By 1968 it had captured 25% of the Hong Kong soft drink market, second only to Coca-Cola.

In Japan, bottled soymilk arrived in about 1957. The first soymilk boom started in about 1980; the many brands of soymilk were all sold in 180 ml aseptic cartons.

In the United States and Europe, soymilk started to become popular in the 1980s. The first two brands sold nationwide were Vitasoy and Edensoy, both aseptically packaged so they did not need refrigeration. The first superstar of soymilks, Silk, was launched by White Wave of Boulder, Colorado, in early 1996. It was sold in the dairy case in gable-top cartons that looked like typical milk cartons.

Plain soy juice is unsweetened, although some soy juice products are sweetened. Salted soy juice is also consumed in China.

The drink is very popular in the hawker culture of Malaysia and many other Southeast Asian countries, with it being a standard offering accompanying meals at Malaysian Chinese stalls. In Malaysia, soybean drink is usually flavoured with either white or brown sugar syrup. The consumer also has the option to add grass jelly, known as leong fan or "cincau" (in the Malay language, adopted from the Chinese equivalents) to the beverage. Sellers of soybean beverage in Penang usually also offer bean curd, a related custard-like dessert, known to the locals as tau hua which is flavored with the same syrup as the soybean milk. In Indonesian it is known as "susu kedele". In Vietnam, the soymilk as well as the soy custard may be flavored with ginger or pandan, a grassy herb with a mild coconut-like flavor. More recently (since 2008), other optional additions to doy beverage have become popular among street vendors and drink stalls around Southeast Asia, including tapioca pearl, sweetened red bean, honey, and black tea.

Yeo's, a drink manufacturer in Singapore and Malaysia, markets a commercialized tinned or boxed version of soybean beverage.

The drink is slowly becoming popular in India as well, where it widely sold in Tetrapaks by various brands like Staeta.

In the West, soy beverage has become a popular alternative to cow's milk, with a roughly similar protein and fat content. Soy juice is commonly available in vanilla and chocolate flavors as well as its original unflavored form. In some Western countries where veganism has made inroads, it is available upon request at cafés and coffee franchises as a cow's milk substitute.

Health and nutrition

Soy juice, original, unfortified

Nutritional value per 100 g (3.5 oz)
Energy	226 kJ (54 kcal)
Carbohydrates	6.28 g
Sugars	3.99 g
Dietary fiber	0.6 g
Fat	1.75 g
Saturated	0.205 g
Monounsaturated	0.401 g
Polyunsaturated	0.961 g
Protein	3.27 g
Tryptophan	0.038 g
Threonine	0.108 g
Isoleucine	0.114 g
Leucine	0.186 g
Lysine	0.131 g
Methionine	0.027 g
Cystine	0.000 g
Phenylalanine	0.113 g
Tyrosine	0.089 g
Valine	0.117 g
Arginine	0.187 g
Histidine	0.061 g
Alanine	0.104 g
Aspartic acid	0.288 g
Glutamic acid	0.487 g
Glycine	0.193 g
Proline	0.147 g
Serine	0.149 g
Vitamins	Quantity %DV†
Thiamine (B1)	5% 0.060 mg
Riboflavin (B2)	5% 0.069 mg
Niacin (B3)	3% 0.513 mg
Pantothenic acid (B5)	7% 0.373 mg
Vitamin B6	5% 0.077 mg
Folate (B9)	5% 18 μg
Vitamin E	1% 0.11 mg
Minerals	Quantity %DV†
Calcium	2% 25 mg
Copper	14% 0.128 mg
Iron	4% 0.64 mg
Magnesium	6% 25 mg
Manganese	10% 0.223 mg
Phosphorus	4% 52 mg
Potassium	4% 118 mg
Selenium	9% 4.8 μg
Sodium	2% 51 mg
Zinc	1% 0.12 mg
Other constituents	Quantity
Water	88.05 g
†Percentages estimated using US recommendations for adults, except for potassium, which is estimated based on expert recommendation from the National Academies.

Soy juice has about the same amount of protein as cow's milk, though the amino acid profile differs. Natural soy juice contains little digestible calcium as it is bound to the bean's pulp, which is indigestible by humans. To counter this, many manufacturers enrich their products with calcium carbonate available to human digestion. Unlike cow's milk, it has little saturated fat and no cholesterol.

Soy products contain sucrose as the basic disaccharide, which breaks down into glucose and fructose. Since soy doesn't contain galactose, a product of lactose breakdown, soy-based infant formulas can safely replace breast milk in children with galactosemia. Like lactose-free cow's milk, soymilk contains no lactose, which makes it a good alternative for lactose-intolerant people. For patients without conditions that limit which sugars they can consume, there is no evidence to support any sugar-related health benefit or detriment to consuming soy beverage instead of cow's milk.

The American Academy of Pediatrics considers soy juice a suitable alternative for children who cannot tolerate human or cow's milk, or whose parents opt for a vegan diet.

Soy juice, like cow's milk, varies in fat content, but the most commonly sold varieties have less fat than whole milk, similar fat content to 2% milk, and more fat than skim/nonfat milk.

Though it has been suggested that soy consumption is associated with a reduction in low-density lipoprotein ("bad cholesterol") and triglycerides, a 2006 study of a decade of soy protein consumption found no association between soy intake and health benefits such as cardiovascular health or cancer rates, and no benefit for women undergoing menopause. Soy was able to replace animal protein, foods high in saturated fats, and other sources of dietary fiber, vitamins and minerals. However, much of the mineral content in soy juice is unassimilable because of high content of phytic acid in soy milk. If soy milk is made into tempeh, the phytic acid content is cut in half.

Research has refuted claims that soy affects bone mineral density. Research has found no link between soy and increased estrogen levels in men, although studies thus far have been limited in duration.

For people who suffer from gout, purine in soy can make the condition worse. The U.S. National Institutes of Health (NIH) recommends gout sufferers limit consumption of soy products (although also suggesting that soy may have health benefits by reducing the risk for heart disease).

Preparation

File:Soy milk I.jpg

Package and glass of Malaysian soy milk

Soy juice can be made from whole soybeans or full-fat soy flour. The dry beans are soaked in water overnight or for a minimum of 3 hours or more depending on the temperature of the water. The rehydrated beans then undergo wet grinding with enough added water to give the desired solids content to the final product. The ratio of water to beans on a weight basis should be about 10:1. The resulting slurry or purée is brought to a boil in order to improve its nutritional value by heat inactivating soybean trypsin inhibitor, improve its flavor and to sterilize the product. Heating at or near the boiling point is continued for a period of time, 15–20 minutes, followed by the removal of an insoluble residue (soy pulp fiber or okara) by filtration.

There is a simple yet profound difference between traditional Chinese and Japanese soy milk processing: the Chinese method boils the filtrate (soy juice) after a cold filtration, while the Japanese method boils the slurry first, followed by hot filtration of the slurry. The latter method results in a higher yield of soy milk but requires the use of an anti-foaming agent or natural defoamer during the boiling step. Bringing filtered soy juice to a boil avoids the problem of foaming. It is generally opaque, white or off-white in color, and approximately the same consistency as cow's milk.

For all raw soybean protein products, heat is necessary to destroy the activity of the protease inhibitors naturally present in the soybean. The pancreas naturally secretes proteases to digest a protein meal. Eating raw soybeans on a regular basis causes the pancreas to hypersecrete, leading to benign tumors of the pancreas.

When soybeans absorb water, the endogenous enzyme, Lipoxygenase (LOX), EC 1.13.11.12 linoleate:oxidoreductase, catalyzes a reaction between polyunsaturated fatty acids and oxygen {hydroperoxidation}. LOX initiates the formation of free radicals, which can then attack other cell components. Soybean seeds are the richest known sources of LOXs. It is thought to be a defensive mechanism by the soybean against fungal invasion.

In 1967, experiments at Cornell University and the New York State Agricultural Experiment Station at Geneva, NY led to the discovery that paint-like, off-flavors of traditional soy juice can be prevented from forming by a rapid hydration grinding process of dehulled beans at temperatures above 80 °C. The quick moist heat treatment inactivates the LOX enzyme before it can have a significant negative effect on flavor. All modern bland soy juices have been heat treated in this manner to destroy LOX.

In 1969, Mattick and Hand at Cornell University made the important discovery that most of the so-called beany flavor in soybeans was not inherent in the beans themselves but was produced by the enzyme lipoxygenase when the split beans came in contact with water. Lipoxygenase could be inactivated and most of the beany flavor removed by either dropping unsoaked soybeans directly into boiling water or by removing any cracked or split beans prior to soaking, then carefully dropping the soaked beans into boiling water.

Normal mature soybeans actually contain three LOX isozymes (SBL-1, SBL-2, and SBL-3) important for undesirable flavor development. One or more of these isozymes have recently (1998) been removed genetically from soybeans yielding soy juice with less cooked beany aroma and flavor and less astringency. An example of a triple LOX-free soybean is the American soybean named "Laura".

The University of Illinois has developed a soy juice that makes use of the entire soybean. What would normally constitute "insolubles" are ground so small by homogenization as to be in permanent suspension.

Cooking

A bowl of soy milk soup seasoned with salt and vinegar, with vegetables and wonton dumplings.

Bottled soy milk as sold in Thailand

Soy juice is found in many vegan and vegetarian food products and can be used as a replacement for cow's milk in many recipes.

"Sweet" and "salty" soy milk are both traditional Chinese breakfast foods, served either hot or cold, usually accompanied by breads like mantou (steamed rolls), youtiao (deep-fried dough), and shaobing (sesame flatbread). The soy beverage is typically sweetened by adding cane sugar or, sometimes, simple syrup. "Salty" soy milk is made with a combination of chopped pickled mustard greens, dried shrimp and, for curdling, vinegar, garnished with youtiao croutons, chopped scallion (spring onions), cilantro (coriander), meat floss (肉鬆; ròusōng), or shallot as well as sesame oil, soy sauce, chili oil or salt to taste.

Soy juice is used in many kinds of Japanese cuisine, such as in making yuba as well as sometimes a base soup for nabemono.

In Korean cuisine, soy milk is used as a soup for making kongguksu, cold noodle soup eaten mostly in summer.

Tofu is produced from soy juice by further steps of curdling and then draining.

Soy juice is also used in making soy yogurt, soy cream, soy kefir and soy based cheese analogues.

Ecological impact

Using soybeans to make milk instead of raising cows may be ecologically advantageous, because the amount of soy that could be grown using the same amount of land would feed more people than if used to raise cows. Cows require much more energy in order to produce milk, since the farmer must feed the animal, which can consume up to 24 kilograms (53 pounds) of food in dry matter (DM) basis and 90 to 180 litres (25 to 50 gallons) of water a day, producing an average of 40 kilograms of milk a day. Because the soybean plant is a legume, it also replenishes the nitrogen content of the soil in which it is grown.

The American soil scientist Dr. Andrew McClung was the first to devise a method to grow soybeans in the Cerrado region of Brazil (tropical savanna). He was awarded with the 2006 World Food Prize.

See also

• Hemp milk
• Chinese cuisine
• Dairy (animal) milk
• Douzhi
• Plant milk
• Soy milk maker
• Tofu (soy milk curd)

References

• Rahab Waweru, M.A., et al. 1967. Effect of processing methods on oxidative off-flavors of soybean milk. Cereal and Food Sciences North Nairobi State University, Ministry of Agriculture. "Soy Milk". Soya.be. Soya. Retrieved August 17, 2005.
• Torres-Penaranda, A.V., et al.1998. Sensory characteristics of soymilk and tofu made from Lipoxygenase-Free and Normal soybeans. Journal of Food Science 63 (6): 1084-1087.
• Smith, A.K. and Circle, S.J. 1972. Soybeans: Chemistry and Technology. AVI publishing.
• Calvert, John (2000). Soymilk Microenterprise: A Treatise on Small-Scale Soymilk Production
• William Shurtleff and Akiko Aoyagi (1979). Tofu & Soymilk Production. Lafayette, California: New-Age Foods Study Center.
• William Shurtleff and Akiko Aoyagi (2000). Tofu & Soymilk Production. 3rd edition. Lafayette, California: Soyfoods Center. ISBN 0-933332-72-6.
• William Shurtleff and Akiko Aoyagi (1994). Soymilk and soymilk products - Bibliography and sourcebook, 1500 to 1993: Detailed information on 3,120 published documents (extensively annotated bibliography), 968 commercial soymilk products, 506 original interviews (many full text) and overviews, 462 unpublished archival documents. Lafayette, California: Soyfoods Center. ISBN 0-933332-84-X.
• Liu, KeShun.1997. Soybeans: Chemistry, Technology, and Utilization. Chapman & Hall.
• Ang, Catharina Y. W., KeShun Liu, and Yao-Wen Huang, eds. (1999). Asian Foods: Science & Technology. Lancaster, Pennsylvania: Technomic Publishing Co.
• Berk, Zeki. Technology of production of edible flours and protein products from soybeans. FAO (UN). 1992.
• Frank M. Sacks MD, et a. (2006) Soy Protein, Isoflavones, and Cardiovascular Health. An American Heart Association Science Advisory for Professionals From the Nutrition Committee in Circulation.

External links

• Cornell University Food and Brand Lab
• Soy Allergy Information Page Asthma and Allergy Foundation of America