Effect of ultrasound and coagulant types on properties of β-carotene bulk emulsion gels stabilized by soy protein

β-carotene is a lipid-soluble nutrient. However, the application of β-carotene in food systems is limited due to its poor water solubility and low bioaccessibility. In this work, we proposed a food-grade soy protein cold-set bulk emulsion gels for β-carotene delivery. In the current study, the formation of cold-set β-carotene bulk emulsion gels was induced by adding CaCl2, glucono-δ-lactone (GDL), and transglutaminase (MTGase). The bioaccessibility (82.39 ± 0.02%) of β-carotene encapsulated in ultrasound-treated MTGase-induced emulsion gels was higher than that in ultrasound-treated emulsions (63.37 ± 0.09%). Moreover, our results demonstrated that the ultrasound-treated MTGase-induced bulk emulsion gels exhibited higher gel strength and water holding capacity (91.02 ± 3.58% and 99.81 ± 0.19%, respectively) than ultrasound-treated CaCl2-induced (37.27 ± 1.19% and 87.37 ± 1.89%, respectively) and GDL-induced samples (58.18 ± 1.38% and 90.43 ± 3.65%, respectively). Furthermore, compared with mechanical homogenization, ultrasonic homogenization improved the β-carotene bioaccessibility and functional properties of bulk emulsion gels. In conclusion, bulk emulsion gels can provide more sensory perceptions and food consumption choices, thus they are promising delivery system of lipid-soluble nutrients.