Ultrasound boosts quality of kefir

Researchers from the South Ural State University (SUSU) (Chelyabinsk, Russia) with colleagues from the Russian State Agrarian University and the National Institute of Technology Warangal (India), have found a way to enhance the health properties of fermented milk products (kefir in particular) significantly through ultrasonic treatment. They share the results of their study published in the Ultrasonics Sonochemistry magazine.

Kefiran, the water-soluble polysaccharide in the kefir grain, has antimicrobial and healing properties and can reduce blood pressure and cholesterol levels in blood serum. The anti-tumor effect and ability to increase immunity are also well-known. All these prompted researchers to try to increase the kefiran content in the consumer products.

Synthesis and analysis of food ingredient (Photo credit: Oleg Igoshin)

"The main objective of our research was to step up the kefiran content in fermented milk drinks. To this end, we treated milk with ultrasound," said Prof. Irina Potoroko, head of the Food Technology and Biotechnology Department at SUSU School of Medicine Biology. She noted that healthy dairy drinks are traditionally produced with milk and then with added fermentation starter. Kefir exopolysaccharide accumulates in the course of fermentation (resulting in kefir from milk). The researchers have added milk sonication to the fermentation process. They say this results in faster kefiran buildup and increased kefiran content in the milk.

"The effects of sonication are interesting; it is not quite clear if ultrasound boosts the development of healthy microorganisms or if it suppresses them and they start producing kefiran as a defense response. We have decided to determine which treatment parameters are required to intensify this process while maintaining the qualities of the consumer product. Mathematical simulations helped establish the best modes and duration of the ultrasound treatment," explained Irina Kalinina, a SUSU associate professor.

Researchers at SUSU School of Medicine Biology have received patents for ultrasound applications in the production of dry extracts and fermented milk drinks, and for reconstituted powdered milk and meat packing.

Postdoctoral researches from India and students from other countries take an active part in scientific inquiries of SUSU School of Medical Biology. It’s important to notice that School of Medical Biology implements new educational program.

“Agrobiotechnology. Development of effective grain disinfection technologies” for international students. Specialists in this field are in demand all over the world, so this program is especially interesting for students from other countries as it stimulates development of new areas of research.