Food scientists turn soy milk residue into healthy probiotic drink

In continuation of my update on Soy Milk

Food scientists at the National University of Singapore (NUS) have given okara - the residue from the production of soy milk and tofu, and is usually discarded - a new lease of life by turning it into a refreshing drink that contains live probiotics, dietary fiber, free isoflavones and amino acids. By encapsulating these nutrients in a beverage, they can be easily absorbed into the body, and promote gut health.

Created using a patented, zero-waste process, the tasty drink can be stored at room temperature for up to six weeks and still retain high counts of live probiotics to better deliver health effects. This is unlike commercially available probiotic drinks which are mainly dairy-based and require refrigeration to maintain their levels of live probiotics. These beverages also have an average shelf-life of four weeks, and do not contain free isoflavones, which have a host of health benefits.

"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 Shao-Quan Liu, who is from the Food Science and Technology Program at the NUS Faculty of Science.

Turning unwanted soy pulp into a nutritious drink

About 10,000 tonnes of okara are produced yearly in Singapore. As it turns bad easily, causing it to give out an unpleasant smell and a sour taste, okara is usually discarded by soy food producers as food waste.

The idea of using fermentation to produce a drink from okara was first conceived by Ms Weng-Chan Vong, a PhD student from the NUS Food Science and Technology Program. 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 realized 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.

Under the guidance of Assoc Prof Liu, Ms Vong took a year to devise a novel recipe that converts okara into a beverage that is fruity and refreshing. She experimented with 10 different yeasts and four different enzymes before coming up with an ideal combination.

The final 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 nutritious drink that achieves a minimum of 1 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.

Next step: Refining the recipe for commercialization

The NUS researchers have filed a patent for their novel 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 Assoc Prof Liu.

Soy foods, cruciferous vegetables may reduce breast cancer treatment’s side effects

In continuation of my update on soy milk

Consuming soy foods (such as soy milk, tofu and edamame) and cruciferous vegetables (such as cabbages, kale, collard greens, bok choy, Brussels sprouts, and broccoli) may be associated with a reduction in common side effects of breast cancer treatment in breast cancer survivors, say a team of scientists led by Georgetown Lombardi Comprehensive Cancer Center.

In the study, published in Breast Cancer Research and Treatment, higher intake of cruciferous vegetables and soy foods were associated with fewer reports of menopausal symptoms. Higher soy intake was also associated with less reported fatigue. The breast cancer survivors studied included 173 non-Hispanic white and 192 Chinese Americans including US-born Chinese and Chinese immigrants.

Researchers say breast cancer survivors often experience side effects from cancer treatments that can persist months or years after completion of treatment. For example, because many treatments designed to prevent breast cancer recurrence inhibit the body's production or use of estrogen, the hormone that can fuel breast cancer growth, breast cancer patients often experience hot flashes and night sweats, among other side effects.

The lead author on the study, Sarah Oppeneer Nomura, PhD, of Georgetown Lombardi, said that while further research is needed in larger study populations and with more detailed dietary data, this project addresses an important gap in research on the possible role of lifestyle factors, such as dietary habits, in relation to side effects of treatments.

"These symptoms can adversely impact survivors' quality of life and can lead them to stopping ongoing treatments, she says. "Understanding the role of life style factors is important because diet can serve as a modifiable target for possibly reducing symptoms among breast cancer survivors."

When study participants were evaluated separately by race/ethnicity, associations were significant among white breast cancer survivors; however; while a trend was seen in the benefit for Chinese women, results were not statically significant. Researchers explain Chinese women typically report fewer menopausal symptoms. Most of them also consume cruciferous vegetables and soy foods, making it difficult to see a significant effect in this subgroup. Indeed, in this study, Chinese breast cancer survivors ate more than twice as much soy and cruciferous vegetables.

Whether the reduction in symptoms accounts for longtime use of soy and cruciferous vegetables needs further investigation, says the study's senior author, Judy Huei-yu Wang, PhD, of Georgetown Lombardi's Cancer Prevention and Control Program.

Results obtained in preclinical studies in animals show that biologically active compounds present in both soy and cruciferous vegetables cause breast cancer cells to grow, but have opposite effects in animals that consume these compounds well before cancer is diagnosed and continue consuming them during and after cancer treatments.

Until more research is conducted, breast cancer patients should not suddenly start eating soy, if they have not consumed it before, says Leena Hilakivi-Clarke, PhD, a professor of oncology at Georgetown Lombardi and a co-author of the study.

Researchers also found suggestive associations with lower reporting of other symptoms, including joint problems, hair thinning/loss and memory less in women who consumed more soy foods, but these associations did not reach statistical significance.

Phytochemicals, or bioactive food components, such as isoflavones in soy foods and glucosinolates in cruciferous vegetables may be the source of the benefit, researchers say. Isoflavones bind to estrogen receptors and exert weak estrogenic effects, among other effects. Glucosinolates in cruciferous vegetables influence levels of metabolizing enzymes that can modulate inflammation and levels of estrogen, possibly attenuating treatment-related symptoms.

Soy foods, cruciferous vegetables may reduce breast cancer treatment’s side effects