Effect of ultrasound pretreatment on structural, physicochemical, rheological and gelation properties of transglutaminase cross-linked whey protein soluble aggregates

[Display omitted] •WPISA was treated by high intensity ultrasound (HUS, ~69 W cm−2).•The treated WPISA solution was incubated with transglutaminase (TGase).•HUS increased the TGase cross-linking degree of WPISA.•HUS facilitated formation of more high molecular weight polymer aggregates.•HUS improved rheological and gelation properties of TGase cross-linked WPISA. A solution (10%, w/v) of whey protein soluble aggregates (WPISA) was pretreated with high-intensity ultrasound (HUS, 20 kHz) for different durations (10–40 min) before incubation with transglutaminase (TGase) to investigate the effect of HUS on the structural, physicochemical, rheological, and gelation properties of TGase cross-linked WPISA. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) results showed that HUS increased the amounts of high-molecular-weight polymers/aggregates in WPISA after incubation with TGase. HUS significantly increased (P