What is soya? What is soya used for? What is its origin? Let us try to find out a few answers about soya.
Soya is a bean obtained from the pods in the soya plant whose scientific name is Glycine max. It is similar to peas and beans and belongs to the same family, legumes. A single pod contain about 2 to 4 soya beans. Soya beans when unripe are green in colour. The usual white ones available in the market are ripe dried beans.
Origins of soya
Soya was domesticated from wild soya, Glycine soja found in central china and cultivated for more than 5000 years in China. The Chinese emperor Shannong elevated it to the level of a sacred plant. Soya spread from China to countries like India, Japan, Thailand, Philippines and other south east Asian regions. However, the rest of the world did not meet soya till the 17th and 18th centuries and its initial introduction into the western world was mostly as a source of cattle feed.
Soya milk is made by soaking the soya beans (not the green ones but the white dried ones) in water and then crushing and squeezing out the milk from the soya. Soya milk is rich in proteins, isoflavones and B vitamins. It is a good alternative to cow’s milk for those who are lactose intolerant. The soya milk available in the market in aseptic containers is usually flavoured with chocolate, strawberry or mango although plain ones are also available. They can be stored without spoilage for several months unlike cow’s milk.
Tofu is the equivalent of cheese obtained from soya milk. It is made by coagulating the proteins in soya milk using salts such as calcium sulfate, calcium chloride or magnesium chloride. Vinegar and citric acid can also be used as coagulants. Tofu has all the benefits of soya milk. It is rich in isoflavones, high quality protein and B vitamins. Apart from this Tofu is also easy to digest and is a good source of calcium and magnesium depending upon the coagulant used.
Tempeh is made from whole soya beans by soaking, slightly cooking and dehulling soya followed by adding a little bit of acetic acid and then fermenting it for a day or two using spores of the fungi Rhizopus Oligosporus. Fermentation binds the soya into a white cake. Tempeh is an excellent source of vitamins as fermentation helps our bodies absorb all its nutrients. Also fermented soya is easily digested by the body.
Miso is a fermented paste like soya product which originated in Japan. Miso is made by mixing soya with grains such as rice wheat or barley along with salt and fungi spores and fermenting it for a period of several days to several years. Miso is quite healthy and has saponin and live enzymes. The only problem is its high salt content
Soya oil is produced by cracking soya beans, heating it and then solvent extraction by using hexane. Soya oil is also sometimes hydrogenated to increase shelf life. Soya oil is used as a vegetable oil and is also a raw material to produce ink, paints, bio diesel etc. Soya oil has come under a lot of criticism due to the use of hexane for its extraction. Hexane poses long term health risks and a small part remains in soya oil
Soybean meat is a byproduct of soybean oil extraction. After the oil is extracted the remaining solid is extruded into various shapes such as chunks. Soya chunks are up to 50% protein. However the use of hexane in the process casts doubts on its health benefits.
Soya sauce is made from soya beans mixed with wheat or barley along with salt and water fermented to form a paste. The paste is then pressed to extract the soya sauce and the remaining product is used as animal feed. Soya sauce is used as a condiment to flavour food.
Edamame is unripe soya boiled in water along with salt. It is served in Japanese restaurants as a snack. It is high in iron, proteins, vitamins and minerals
Health benefits of soya
Soya is known to be the only vegetarian food providing all the essential amino acids needed for the human body. There are 20 amino acids required by the human body out of which 8 are essential amino acids that can’t be produced by the body. Soya has all the eight amino acids and is a great source of protein for vegetarians. Soya milk also supplements the diet of lactose intolerant population. Soya is rich in vitamins, minerals and fibers. It has an abundance of B vitamins that play in important role in cell metabolism. Soya has isoflavones which are powerful antioxidants. However isoflavones are phytoestrogens and mimic the female hormone estrogen. Soya is also supposed to reduce the risk of coronary heart diseases by lowering cholesterol and preventing plaque buildup in arteries. It also has been attributed to reduce risk of prostrate cancer in men and breast cancer in women.
Ecological impact of cultivation
The major producers of soya are the U.S and Brazil producing about 62% of world’s soyabean output of around 250 million metric tonnes. Brazil is the largest exporter of soya exporting about 38 million tonnes followed by America at around 35 million tonnes. The impact of its cultivation in South America is a concern for global environmentalists as vast tracts of the Amazon forest have been cleared for soya farms. The Amazon forests have a fragile ecosystem and are home to large varieties of plant and animal species. It also represents more than half of the rainforests in the planet. Loss to the rainforest which accounts for 20% of the world’s oxygen can have a serious impact on global climate. Also most of the soya cultivated is genetically modified to be tolerant to pesticides such as roundup. Monsanto corporation has created roundup ready soya through alteration in soya gene structure. The long term effects of such genetic alteration are not yet known.
Soya and potential health risks
The phytoestrogens in Soya are believed to reduce male fertility by increasing etrogen mimicing hormones. They are also claimed to bring an early onset of puberty in girls and affect brain development of infants. Notwithstanding these claims soya has several health benefits and its correct use can have an overall beneficial effect for humans as well as animals. In ancient China, soya was mostly fermented before use. This reduced the levels of phytoestrogens and other harmful chemicals in soya. Organic soya prepared in the traditional method could be the way forward in the soya story.