Ultrasound-assisted enhancement of microbial, physicochemical, and bioactive properties in Lactobacillus...

This research assessed the impacts of ultrasound on fermentation dynamics and bioactive properties in milk fermented with Lactobacillus helveticus. Ultrasound was applied to milk (MU + L), bacterial culture (M + LU), both (MU + LU), or the inoculated mixture [(M + L)U], and samples were analysed during a 24 h fermentation. Results demonstrated that ultrasound significantly enhanced microbial viability, especially in MU + LU. Acidification occurred more rapidly in ultrasound-treated samples, with MU + LU achieving the lowest pH(3.31). Ultrasound also improved antioxidant potential, with DPPH radical scavenging and ascorbate oxidation inhibition reaching 79.8 % and 28.4 %, respectively, in MU + LU. Furthermore, inhibitory activities against α-amylase, α-glucosidase, ACE, and lipase were significantly higher in ultrasound-treated samples, again with MU + LU showing the most pronounced effects (47.2 %,43.4 %,42.9 %, and 34.6 %, respectively). These findings highlight the synergistic advantages of applying ultrasound to milk and culture, offering a promising green, non-thermal approach to accelerate fermentation and improve microbial viability, antioxidant activity, and functional health-promoting properties in fermented dairy products.