INTERNATIONAL DAIRY JOURNAL, vol.141, pp.105617, 2023 (SCI-Expanded)
Application of high intensity ultrasound (HIUS) was compared with conventional heat treatment for extending shelf life of a fermented milk beverage. Beverage samples were subjected to HIUS (24 kHz, 400 W) at different power levels (25–100%) and temperature (20–60 °C) or conventional heat treatment (60–70 °C), each for 10 min. Acidity, serum separation, rheological, microbiological and sensory properties of the beverages were measured. HIUS at 20 °C was not sufficient for inactivation of lactic acid bacteria and moulds/yeasts; moreover, it lowered consistency and increased serum separation. HIUS at 60 °C resulted in similar levels of microbial inactivation, consistency and serum separation to those obtained by heat 60 °C treatment. Heat treatment at 70 °C yielded the highest microbial inactivation and the most stable structure in the beverage. HIUS treatment was found to reduce particle size but caused foreign odour and taste in the beverage in sensory analysis.