Berlin University of Technology spray dries for added probiotics

Researchers at the Berlin University of Technology are taking cues from a century-old spray drying technology to see if it could be developed to make better products for the food and pharmaceutical industries. They are now looking for investors and partnership from industry players to examine the technique for conserving lactic acid bacteria.

The spray-dry technology uses heated air to drive moisture quickly from flavour components. It works well with established encapsulation systems to produce dry powders without disturbing the encapsulation shells. Spray dryers were first made in the early 1900s and are a standard technology in the food industry, especially in the dairy industry.

The major benefit of creating a spray is it could generate a large surface area for transferring the injected energy to the product. (1 litre of water transformed into droplets with an average diameter of 0.2 millimetres will result in a total contact area of 30 square metres). The advantage of spray drying is that both mass and energy are transferred in a very short time without using an exchange surface and keeping the product temperature well below 100 °C.

These conditions make the process ideal for any application where products are sensitive to temperature. This includes nearly all products derived from milk and more generally all food products where maximum retention of the original properties is important. And it could be extend to living probiotic bacteria.

Probiotics are dietary supplements containing potentially beneficial bacteria or yeast, with lactic acid bacteria (LAB) being the most common used microbes used. LAB have been used in the food industry for many years, because they are able to convert lactose into lactic acid. This not only provides the characteristic sour taste of fermented dairy foods such as yogurt, but acts as a preservative, by lowering the pH and creating less room for spoilage organisms to grow.

The researchers are now studying to see if spray dried cultures in replacing the usual liquid or frozen starter or freeze dried cultures in the production of fermented products. Energy consumption of spray drying is said to be 6 to 10 times lower compared to freeze drying.