Probiotic drink from soymilk residue

August 27, 2018

27 Aug 2018. NUS food scientists have developed a bioprocessing method that can transform unpleasant-smelling okara, a byproduct from soymilk production, into a nutritious, fruity probiotic drink.Soymilk is a commonly consumed drink in Asia and is made from soybeans. The soybean residue that remains after the soymilk production process is known as okara. Tofu (bean curd) manufacturing is also an important contributor to okara generation. Okara is usually white or yellowish in colour and is seldom consumed. This is partly due to its unpleasant fishy smell and gritty taste. Singapore produces about 10,000 tonnes of okara annually as a byproduct. Most of it is disposed in landfills. This creates wastage in the food production process.

A research team led by Prof LIU Shao Quan from the Food Science and Technology Programme at the Department of Chemistry, NUS has developed a bioprocessing method using a unique mix of selected enzyme, probiotic and yeast to turn okara into a nutritious and fruity beverage within 36 hours. The drink contains live probiotics and soluble fibre. It also has twice the amount of free amino acids and antioxidants (free isoflavones) compared to unprocessed okara. These nutrients promote gut health and are beneficial to our body. The bioprocessing method can potentially convert okara food waste from the soymilk industry into a more valuable product.

Prof Liu said, “The enzyme makes the okara less gritty. The yeast converts unpleasant-smelling odorants in okara into fruity-smelling ones, and helps in keeping the probiotics alive. This beverage is a natural, non-dairy alternative to dairy probiotic drinks.”

Due to the unique combination of microorganisms used, this patented okara beverage can be stored at room temperature for up to six weeks and still maintains at least 10 billion live probiotic count in a 100 ml serving. In comparison, commercially available probiotic drinks typically have a shelf-life of about four weeks and must be kept refrigerated.

Ms VONG Weng Chan, a Ph.D. student on the research team said, “By collaborating with food companies, we can potentially bring this beverage to consumers. This could provide health-conscious consumers with another healthy beverage choice.”

Figure shows that okara (soybean residue) can be converted into a nutritious and refreshing okara probiotic beverage using a combination of enzyme and beneficial microorganisms (live probiotic and yeast).