Combination of microwave heating and transglutaminase cross-linking enhances the stability of limonene emulsion carried by whey protein isolate

In this study, we examined the effect of transglutaminase (TG) cross-linking time (0 h, 2 h, 4 h, 8 h, and 12 h) on the stability of limonene emulsion loaded by microwave-heated WPI (MWPI). Size exclusion chromatography results showed that molecular weight of TG-treated MWPI and WPI was enhanced with the increase in TG cross-linking time (0–12 h). Microwave and TG cross-linking decreased particle size (7.55%) and increased ζ-potential (5.33%) and protein adsorption (4.58%) of WPI emulsion at TG cross-linking time of 12 h. CLSM results showed smaller droplet size of MWPI-TG emulsion and its uniform size. The obtained limonene emulsion loaded by MWPI-TG at 12 h showed the lowest creaming index and the strongest oxidative stability under aerobic conditions after 10thdays of storage. Thus, the combination of microwave heating and TG cross-linking effectively enhanced the stability of limonene emulsion stabilized by WPI and facilitating the application of WPI in the fields of food, medicine, cosmetics, and other areas.