Modulating the in vitro digestion of heat-set whey protein emulsion gels via gelling properties modification with sequential ultrasound pretreatment

Abstract

The influences of the ultrasound frequency and pretreatment duration on the viscoelastic properties and microstructure of whey protein emulsion gels (WPEG) were investigated using dual-frequency ultrasound in sequential mode. And the effect of ultrasound modification of whey protein on the in vitro digestion of WPEG was assessed. The results showed that ultrasonic pretreatment could improve the viscoelastic properties and microstructure of WPEG. WPEG pretreated with an ultrasound sequence of 20 and 28 kHz for 10 min exhibited better storage modulus (G′) and microstructure compared to the control. The final G′ and final tanδ of WPEG increased by 184% and 8% respectively compared with the control. CLSM and SEM showed that ultrasound pretreatment could result in the formation of a compact and fine network. The ultrasound pretreatment improved the digestion of WPEG by enhancing the acid and base consumption during gastric and intestinal digestion, respectively. It was suggested that dual-frequency ultrasound in sequential mode could influence the fate of WPEG during gastrointestinal digestion by changing the microstructure of WPEG. Dual-frequency ultrasound could potentially be used to develop foods with new nutritional properties.