About 10,000 tonnes of okara – the residue from the production of soy milk and tofu – are produced yearly in Singapore.
They are usually discarded by soy food producers as food waste, as they turn bad easily, giving out an unpleasant smell and a sour taste.
Food scientists at the National University of Singapore (NUS) have created a way to give okara a new lease of life by turning it into a healthy probiotic drink.
Created using a patented, zero-waste process, the refreshing drink contains live probiotics, dietary fibre, free isoflavones and amino acids. These nutrients can be easily absorbed into the body, and promote gut health.
Commercially available probiotic drinks are mainly dairy-based and require refrigeration to maintain their levels of live probiotics.
The okara beverage, on the other hand, can be stored at room temperature for up to six weeks and still retain high counts of live probiotics to better deliver health effects.
“Okara has an unpleasant smell and taste – it smells fishy, tastes bland, and has a gritty mouthfeel," said project supervisor Associate Professor Liu Shao Quan, who is from the Food Science and Technology Programme at the NUS Faculty of Science. "
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.”
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 Programme.
She recounted, “Fermented soy products, such as soybean paste and miso, are common in Asian food culture. When I was young, my grandparents explained to me how these fermented foods are made. The fermentation process was like magic to me – it transforms bland food into something delicious.”
“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,” she added.