Effects of ultrasonic pretreatment on the molecular conformation, gel texture, and rheological properties of oat-whey dual-protein gel induced by lactic acid bacteria fermentation

Abstract

The development of novel fermented nutritional foods based on plant-animal protein combinations remains challenging due to the limited gel- forming ability and structural regulation of dual-protein systems. This study investigated the effects of ultrasound pretreatment (0–600 W) of oat protein-whey protein dispersions before lactic acid bacteria (LAB) fermentation on the gel and structural properties of the resulting dual-protein gels (OWLG). Ultrasound pretreatment regulated protein aggregation and gel network formation in a power-dependent manner. The 300 W pretreatment group exhibited the smallest particle size (137.30 ± 1.46 nm), the shortest gelation time (5.0 ± 0.06 h), and improved texture, water-holding capacity, and rheological behavior. Structural analyses revealed that 300 W ultrasonic pretreatment promoted protein rearrangement, increasing the β-sheet content to 48.36 ± 0.16% and resulting in the most compact and stable gel network. This study provides a promising strategy for regulating cereal-animal protein fermented gels and developing functional fermented nutritional foods.