Turning Soy Pulp Into A Probiotic Drink

Scientists in Singapore have used a cocktail of enzymes, probiotics and yeast to produce a nutrient-rich beverage from food waste.

AsianScientist (Sep. 10, 2018) – A research group in Singapore has turned residue from the production of soy milk and tofu, known as okara, into a nutritious drink. Their findings are published in Applied Microbiology and Biotechnology.

About 10,000 tons of okara are produced yearly in Singapore. As okara turns bad easily, it is usually discarded by soy food producers as food waste.

In this study, food scientists at the National University of Singapore (NUS) have given okara a new lease of life by turning it into a drink that contains live probiotics, dietary fiber, free isoflavones and amino acids. The idea of using fermentation to produce a drink from okara was first conceived by Ms Vong Weng Chan, a PhD student from the NUS food science and technology program.

“During my undergraduate studies at NUS, I worked on a project to examine how soy milk can be infused into different food items, and I realised that a huge amount of okara was being discarded. It occurred to me that fermentation can be one good way to convert unwanted okara into something that is nutritious and tastes good,” said Vong.

The recipe uses the probiotic strain Lactobacillus paracasei L26, the Viscozyme® L enzyme and the Lindnera saturnus NCYC 22 yeast to convert the okara into a drink that achieves a minimum of one billion probiotics per serving, which is the current recommendation by the International Scientific Association for Probiotics and Prebiotics to achieve maximum health benefits.

The drink, which takes about one and a half days to produce, also contains free isoflavones, which are naturally occurring antioxidants that maintain cardiovascular health, as well as dietary fiber and amino acids. It can also be stored at room temperature for up to six weeks and still retain high counts of live probiotics. This is unlike commercially available probiotic drinks which are mainly dairy-based and require refrigeration.

“Okara has an unpleasant smell and taste—it smells fishy, tastes bland and has a gritty mouthfeel. Our breakthrough lies in our unique combination of enzymes, probiotics and yeast that work together to make okara less gritty and give it a fruity aroma while keeping the probiotics alive. Our final product offers a nutritious, non-dairy alternative that is eco-friendly,” said project supervisor Associate Professor Liu Shao Quan of NUS.

The researchers have filed a patent for their technique and are currently experimenting with different enzymes and microorganisms to refine their recipe. They are also looking to collaborate with industry partners to introduce the drink to consumers.

“In recent years, the food and beverage industry has been intensifying efforts to develop products that appeal to consumers who are increasingly health conscious. Our new product offers soy food manufacturers a viable solution to reduce waste, and also enables them to provide a healthy and eco-friendly beverage for their customers,” said Liu.

The article can be found at: Vong et al. (2017) Biotransformation With Cellulase, Hemicellulase and Yarrowia lipolytica Boosts Health Benefits of Okara.


Source: National University of Singapore; Photo: Shutterstock.
Disclaimer: This article does not necessarily reflect the views of AsianScientist or its staff.

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