Ultrasound treatment to attenuate fermentation in probiotic innovative beverages

The concept of healthy food for healthy life leads food companies and scientists towards the formulation of new probiotic foods. Plant and fruit-based beverages are becoming intensively studied as an alternative to dairy products as probiotic carrier. In the development of probiotic foods there is a high regard for the consumer who demands not only healthy and safety products, but which is also tasty and pleasant. The metabolization of food components and the release of bacteria metabolites into the beverage can lead to the deviation of its chemical, physical, and sensory characteristics, affecting consumer general acceptance. Therefore, the main challenge in the production of new probiotic foods is to control the food-probiotic interaction. The concept of attenuation has been applied on starter culture to control and/or accelerate the ripening phase in cheese production. More recently, attenuation has been proposed as a technological approach to modulate the metabolism of probiotic microorganisms to avoid acidification and post-acidification and, thus, changes in the sensory profile of probioticated food products.

Sonication of cell suspension will be carried out by using an ultrasonic probe sonicator. The parameters of the treatment, power level, duty cycle (the percentage of time during which the ultrasound signal is “on”) and time, will be applied at different values. After the sonication treatments, cultures will be examined for their metabolic activity (e.g. fermentation) and cell surface properties (i.e. auto-aggregation, hydrophobicity, biofilm formation attitude). Moreover, the expression level of some genes will be evaluated by using a RT-PCR analysis.

Effective ultrasound treatment protocols to reduce the metabolic activity of probiotic cultures.