Impact of ultrasound-assisted fermentation on buffalo yogurt production: Effect on fermentation kinetic and on physicochemical, rheological, and structural characteristics

•US-assisted fermentation increased the acidification rate (up to 41%) of buffalo yogurt.•Fermentation in the bath US reduced the fermentation time (up to 25%) of yogurt.•Gels produced for 1–2 h under US had higher WHC (up to 35%) and ηapp (up to 246%).•Ultrasound-assisted fermentation did not impact the viability of lactic acid bacteria.•Sugar addition (5%) improved the yogurt quality (higher WHC and consistency index). This work evaluated the buffalo milk acidification kinetics using partially or fully ultrasound-assisted fermentation and yogurt characteristics without or with sugar (5%). The results showed that assisted fermentation in an ultrasonic bath (25 kHz, 38 W/L) accelerates the fermentation rate (up to 41% increase), reducing the fermentation time (up to 2 h), and, in some conditions, improved the yogurt quality. Samples produced by US-assisted fermentation under 1 or 2 h had higher water holding capacity (up to 35%), consistency index (up to 423%), and apparent viscosity (up to 246%), explained by the formation of a stronger gel, as elucidated by microscopy images. In contrast, no differences in pH, acidity, and lactic acid bacteria viability were observed. Additionally, sucrose contributed positively to the yogurt quality, improving gel formation. Therefore, buffalo milk fermentation under US (up to 2 h) is an interesting strategy that accelerates fermentation and improves the buffalo yogurt quality. [Display omitted]