Table 3.

Examples of protein-based emulsion gels for the delivery of various bioactives.

Protein Type	Modification	Ingredient	Homogenization Technology	Gelation Triggers	Bioactive Components	Main Findings	References
Whey protein isolate	High hydrostatic pressure (600 Mpa) to obtain protein gels	Canola oil	Ultra-high-speed homogenization (12,000 rpm for 1 min)		Curcumin	The whey protein isolates stabilized emulsion gels provided a better protection for curcumin (remained about 70% of the initial amount) after storage for 4 h under light. Higher release of curcumin under in vitro intestinal conditions.	[85]
	No	Medium chain triglycerides (MCT)	Homogenization (9,000 rpm for 90 s) and Microfluidization (18000 psi, 2 cycles)	Heat treatment	β-carotene	Emulsion gels systems effectively protected β-carotene. The effect of adding polysaccharide on bioactive substances was related to the effect of polysaccharide on gel structure.	[54]
	Heated treatment (90 °C for 5 min)	Sunflower oil	Homogenization (10,000 rpm for 1 min) and Microfluidization (50 MPa, 3 passes)	Acidification treatment (Glucono-δ-lactone)	Modulate volatile release (propanol, diacetyl, pentanone, hexanal, and heptanone)	Emulsion-filled protein gels slowed the volatile release by varying the rheological properties of the gels.	[11]
β-lactoglobulin	Heated treatment (85 °C for 45 min)	Sunflower oil	Homogenization (20,000 rpm for 2 min) and Microfluidization (100 MPa for the first-stage, 10 MPa for second-stage)	Addition of ions (Ca2+)	α-tocopherol	The gel structure of cold-set β-lactoglobulin emulsion gels improved the chemical stability of α-tocopherol.	[9]
Egg yolk granule protein	No	Sunflower oil	Homogenization (15,000 rpm for 1 min)	Addition of ions (Ca2+)	β-carotene	A more uniform and dense emulsion gel structure of pH 4.0 than pH 7.0 improved storage stability, FFA releasing, and chemical stability of β-carotenes.	[174]
Soybean protein isolate	Soybean protein isolate (final concentration 7%) with pectin (final concentration 3%)	Soybean oil	Homogenization (20,000 rpm for 5 min)	Ultrasonication (0, 150, 300, 450, and 600 W, for 15 min) and then heat treatment	β-carotene	High intensity ultrasound treatment improved the stability of emulsion gels. High intensity ultrasound treatment enhanced the stability of β-carotene digestion in vitro digestion.	[8]
	Soybean protein isolate (6.0%, w/w) with sugar beet pectin (2.0%, w/w) and then heated treatment (85 °C for 15 min)	Medium-chain triglycerides	Homogenization (10,000 rpm for 3 min) and Microfluidization (30 MPa, 5 passes)	Acidification treatment (Glucono-δ-lactone) and then added laccase/Enzyme treatment (Transglutaminase) and then added laccase	The hydrophilic phase was loaded with the riboflavin, and the lipophilic phase (MCT) was loaded with β-carotene	Compared with the emulsion gel induced by glucono-δ-lactone, the structure of the emulsion gel induced by transglutaminase was denser. The release of both β-carotene and riboflavin was regulated by the gel network induced by different induction methods.	[26]
	Heated treatment (90 °C for 30 min)	Sunflower oil	Homogenization (14,000 rpm for 3 min) and Ultrasonication (20 kHz, 90 W for 3 min)	Addition of ions (Ca2+)/Acidification treatment (Glucono-δ-lactone)/Enzyme treatment (Transglutaminase)	β-carotene	Bioaccessibility of β-carotene in bulk emulsion gels was higher than that of in emulsions. The addition of different coagulants affected β-carotene emulsion gels.	[148]
Zein	Zein with heated (150 °C) food-grad glycerol solutions	Soybean oil	Soybean oil was preheated to 95 °C and was added to the heated zein-glycerol mixed solutions and homogenization (10,000 rpm for 3 min)		β-carotene	The formation of emulsion gels significantly enhanced the UV photo-stability of β-carotene. The addition of β-carotene delayed the oxidation of the corresponding oil phase during storage.	[175]