Researchers develop world’s first tofu whey alcoholic beverage

28 Nov 2017 --- A research team from the National University of Singapore (NUS) has successfully turned tofu whey, a liquid that is generated from the production of tofu and is often discarded, into an alcoholic beverage named Sachi. The innovative fermentation technique also enriches the drink with isoflavones, antioxidants that have many health benefits.

The creation of Sachi was initiated a year ago by Associate Professor Liu Shao-Quan and his Ph.D. student Mr. Chua Jian-Yong, both of whom have an interest in sustainable food production. Both are from the Food Science and Technology Program at the NUS Faculty of Science.

“The traditional way of manufacturing tofu produces a large amount of whey, which contains high levels of calcium and unique soya nutrients such as isoflavones and prebiotics,” says Chua. “Hence, disposing of tofu whey is wasteful. Very little research has been done to transform tofu whey into edible food and beverage products.”

“I had previously worked on alcohol fermentation during my undergraduate studies in NUS, so I decided to take up the challenge of producing an alcoholic beverage using the whey,” Chua adds. “The drink turned out to be tasty, which is a pleasant surprise.”

Turning waste into tasty beverage
Tofu, also known as bean curd, is a popular food made from soybeans. One of the most common methods of producing tofu is by curdling freshly boiled soya milk, cooling it, and pressing it into a solid block, NUS explains. During the pressing process to remove excess water, tofu whey is generated.

However, when tofu whey is discarded as an untreated waste, it creates environmental pollution as the protein and soluble sugars in the whey could contribute to oxygen depletion in the waterways. In contrast, upcycling tofu whey can be a means of generating economic returns for businesses.

“The health benefits associated with soy products, coupled with changing preferences towards vegetarian diets, have fueled the growth of tofu production,” explains Associate Professor Liu. “As a result, the amount of tofu whey has also increased proportionally.”

“Alcoholic fermentation can serve as an alternative method to convert tofu whey into food products that can be consumed directly,” Associate Professor Liu continues. “Our unique fermentation technique also serves as a zero-waste solution to the serious issue of tofu whey disposal.”

Under the guidance of Associate Professor Liu, NUS reports that Chua took about three months to come up with a unique recipe to make an alcoholic beverage from tofu whey.

Chua first made fresh soya milk from soybeans, and then used the soya milk to make tofu. In the course of making tofu, he collected the whey. Sugar, acid and yeast were added to the tofu whey, and the concoction was fermented to produce the alcoholic beverage. Chua also designed a novel fermentation technique which utilizes the tofu whey fully without generating any waste. The whole process of making the alcoholic beverage takes about three weeks.

Biotransformation of tofu whey yields benefits
Altering the composition of tofu whey via biotransformation methods converts its strong beany odor into a fruity, sweet flavor, and extends the shelf life of tofu whey from less than one day to about four months. In addition, after fermentation, the bound isoflavones that were present in the tofu whey were transformed into free isoflavones that can be absorbed more easily by the human body. The result is a refreshing beverage that is a tad sweet, with fruity and floral notes and has an alcohol content of about 7 to 8 percent.

The team has filed a patent for the novel process of making Sachi, and they are looking to collaborate with industry partners to introduce the drink to consumers. Mr. Chua is currently working to double the shelf life of the drink without the use of commonly used preservatives like sulfur dioxide.