Whey Protein Emulsion Gels Research Articles

Understanding of formation, gastrointestinal breakdown, and application of whey protein emulsion gels: Insights from intermolecular interactions.

Whey protein emulsion gel is an ideal model food for revealing how the multilength scale food structures affect food digestion, as their structure and mechanical properties can be precisely manipulated by controlling the type and intensity of intermolecular interactions between protein molecules. However, there are still significant understanding gaps among intermolecular interactions, protein aggregation and gelation, emulsion gel formation, gel breakdown in the gastrointestinal tract (GIT), and the practical use of whey protein emulsion gels, which limits their GIT-targeted applications. In this regard, the relationship between the structure and digestion behavior of heat-set whey protein emulsion gels is reviewed and discussed mainly from the following aspects: (1) structural characteristics of whey protein molecules; (2) how different types of intermolecular interactions influence heat-induced aggregation and gelation of whey protein in the aqueous solutions and the oil-in-water emulsions, and the mechanical properties of the final gels; (3) functions of the mouth, the stomach, and the small intestine in processing of solid foods, and how different types of intermolecular interactions influence the breakdown properties of heat-set whey protein emulsion gels in GIT (i.e., their respective role in controlling gel digestion). Finally, the implications of knowledge derived from the formation and gastrointestinal breakdown of heat-set whey protein emulsion gels for developing controlled delivery vehicles, human satiety enhancers, and sensory modifiers are highlighted.

Fabrication and characterisation of whey–pea protein‐based emulsion gels induced by transglutaminase cross‐linking

Food industry has partially replaced animal proteins with plant‐derived alternatives, and effects of combining these two types on properties of food systems need to be elucidated. This study fabricated and characterised emulsion gels of mixed whey and pea protein, varying protein mass ratios from 100:0 to 0:100 and oil volumes from 30% to 45%, induced by transglutaminase cross‐linking. An increase in pea protein led to larger particle size and reduced surface charge in the solutions. Emulsion droplet size ranged from 0.60 to 15.17 μm, increasing with higher levels of pea protein and oil. Mixed protein gels exhibited significantly greater hardness compared to gels with individual proteins. Water‐holding capacity of pure whey protein emulsion gels exceeded 90%, while the value remained above 80% when pea protein was less than 50%. Partially replacing whey protein with pea protein may have potential applications in food products such as salad dressings and cheese.

Effect of non-covalently bound alkaline amino acids on the structural characterization, microstructure, and rheological properties of whey protein emulsion gel

The objective of this study was to explore the impact of L-arginine (Arg) and L-lysine (Lys) on the structural changes and rheological properties of whey protein isolate (WPI) emulsion gels through the utilization of multi-spectroscopic techniques and rheological analysis. The results indicated that the incorporation of Lys/Arg caused WPI molecules to become unfolded, thus exposing hydrophobic amino acids and altering the microenvironment of aromatic amino acids. Microstructural studies revealed that WPI emulsion gels containing 0.5% Lys or 2% Arg resulted in a more uniform and compact network structure. This phenomenon could be attributed to the capability of Lys/Arg to improve the hydrophobic interactions and hydrogen bonding between molecules during gel formation, ultimately leading to a network structure characterized by excellent rheological properties, textural properties, and water-holding capacity. These findings provide a theoretical for the development of emulsion gels with improved structural and rheological properties.

Fibrous whey protein mediated homogeneous and soft-textured emulsion gels for elderly: Enhancement of bioaccessibility for curcumin

Homogeneous and soft-textured food gels are critical for designing precise and personalized nutrient food for elderly. Effects of whey protein morphology (fibrous and granular) with/without NaCl addition on oil-water state and texture properties of protein emulsion gels were investigated, to explore the feasibility of developing homogeneous and soft-textured food for elderly. Lower gelation temperature and higher stability of its emulsion droplets, resulted in fibrous whey protein emulsion gels (FWPG) had even distribution of embedded oil droplets, compared to native whey protein emulsion gels. FWPG had the lowest hardness and chewiness, and exhibited better tolerance to the harden effects of NaCl on emulsion gels. FWPG can deliver curcumin more effectively during simulated gastrointestinal digestion, as evidenced by higher retention ratio and enhancement of bioaccessibility (increased by ∼ 20 %). This study provided new strategy to fabricate a homogenous emulsion gel using fibrous whey protein and to design multi-nutrient food gels for elderly.

Improving the structure and properties of whey protein emulsion gel using soluble interactions with xanthan and basil seed gum.

Applying hydrocolloids in the structure of protein emulsion gel can improve its properties. Interaction of whey protein concentrate (WPC) (5%) with xanthan gum (XG) and basil seed gum (BSG) at different concentrations (0.2%, 0.4%, and 0.6%) was investigated to improve mechanical and structural properties of emulsion gel. Results illustrated that gums created a stronger structure around the oil droplets, which confocal images approved it. Also, the particle size decreased and uniformed by cooperating 0.6% gum in comparison with WPC (46.87 μm). The lowest and highest hardness values were observed in emulsion gel formed by WPC (1.27 N) and 0.6BSG: WPC (3.03 N), respectively. Also, the increase of gum concentration had a positive on consistency parameter of texture, so the value was 11.48 N s in WPC emulsion gel and it reached 0.6BSG: WPC (25.71 N s) and 0.6XG: WPC (19.96 N s). Evaluating the stability of the treatments by centrifugation indicated that 0.6BSG: WPC (89.10%) and 0.6XG: WPC (74%) had the highest level of stability. Increasing gum concentration increased the consistency and viscosity. Also, the viscoelastic properties of emulsion gel improved by 0.6% BSG. The elastic modulus of the WPC, 0.6XG: WPC, and 0.6BSG: WPC emulsion gels at the same frequency (1 Hz) was 240.90, 894.59, and 1185.61 Pa, respectively. In general, the interaction of WPC solution with hydrocolloids, especially BSG, is suggested to prepare more stable and elastic emulsion gels.

Impact of Combined Thermal Pressure Treatments on Physical Properties and Stability of Whey Protein Gel Emulsions.

Emulsion gels are gaining interest as fat replacers due to their benefits associated with calorie reduction and their versatility in a wide range of products. Their production process needs to be tailored to obtain the desired stability and physicochemical properties. This study investigated the effect of heat (70, 80, and 90 °C) and pressure (5, 10, and 15 MPa) to produce whey protein emulsion gels using a pilot-scale tubular heat exchanger equipped with a homogenization valve. Both temperature and pressure determined a significant effect (p < 0.05) on the rheological moduli, with the treated samples displaying a predominant elastic behavior. The treatments also showed an improved pseudoplasticity due to the significant reduction in the flow behavior index (p < 0.05). All the samples showed a bimodal particle size distribution; by increasing the temperature up to 80 °C, a reduction in Dv50 (50th percentile) values compared to the control samples was observed. At 90 °C, the Dv50 value increased because of coalescence and flocculation phenomena occurring during or immediately after processing. The greater aggregation and structural development obtained with stronger process conditions improved the stability of the emulsions. The results show the capability to produce gel emulsions with good physical properties that could be proposed as food ingredients to substitute fats in food products.

Intermolecular forces regulate in-vitro digestion of whey protein emulsion gels: Towards controlled lipid release

HypothesisThe utilization of emulsion-filled protein hydrogels for controlled lipid release in the gastrointestinal tract (GIT) displays great potential in drug delivery and obesity treatment. However, how intermolecular interactions among protein molecules influence lipid digestion of the gels is still understudied. ExperimentsDifferently structured whey protein emulsion gels were fabricated by heating emulsions with blocking of disulfide bonds (the “noncovalent” gel), noncovalent interactions (the “disulfide” gel), or neither of these (the “control” gel). The intermolecular interactions-gel structure-lipid digestion relationship was investigated by characterizing structural/mechanical properties of the gels and monitoring their dynamic breakdown in a simulated GIT. FindingsAlthough the disulfide-crosslinked protein network formed thick interfacial layers around oil droplets and resisted intestinal proteolysis, the “disulfide” gel had the fastest lipolysis rate, indicating that it could not inhibit the access of lipases to oil droplets. In contrast, the “noncovalent” gel was more susceptible to in-vitro digestion than the “control” gel because of lower gel strength, resulting in a faster lipolysis rate. This demonstrated that intermolecular disulfide bonds and noncovalent interactions played distinctive roles in the digestion of the gels; they represented the structural backbone and the infill in the gel structure, respectively.

Digestion behaviour of capsaicinoid-loaded emulsion gels and bioaccessibility of capsaicinoids: Effect of emulsifier type

In this study, the effect of emulsifier type, i.e. whey protein versus Tween 80, on the digestion behaviour of emulsion gels containing capsaicinoids (CAPs) was examined. The results indicate that the CAP-loaded Tween 80 emulsion gel was emptied out significantly faster during gastric digestion than the CAP-loaded whey protein emulsion gel. The Tween-80-coated oil droplets appeared to be in a flocculated state in the emulsion gel, had no interactions with the protein matrix and were easily released from the protein matrix during gastric digestion. The whey-protein-coated oil droplets showed strong interactions with the protein matrix, and the presence of thick protein layer around the oil droplets protected their liberation during gastric digestion. During intestinal digestion, the CAP-loaded Tween 80 emulsion gel had a lower extent of lipolysis than the CAP-loaded whey protein emulsion gel, probably because the interfacial layer formed by Tween 80 was resistance to displacement by bile salts, and/or because Tween 80 formed interfacial complexes with bile salts/lipolytic enzymes. Because of the softer structure of the CAP-loaded Tween 80 emulsion gel, the gel particles were broken down much faster and the oil droplets were liberated from the protein matrix more readily than for the CAP-loaded whey protein emulsion gel during intestinal digestion; this promoted the release of CAP molecules from the gel. In addition, the Tween 80 molecules displaced from the interface would participate in the formation of mixed micelles and would help to solubilize the released CAP molecules, leading to improved bioaccessibility of CAP. Information obtained from this study could be useful in designing functional foods for the delivery of lipophilic bioactive compounds.

Application of whey protein emulsion gel microparticles as fat replacers in low-fat yogurt: Applicability of vegetable oil as the oil phase.

Low-fat, healthy yogurt is becoming increasingly favored by consumers. In the present study, whey protein emulsion gel microparticles were used to improve the quality of low-fat yogurt, and the effects of vegetable oil emulsion gel as a fat substitute on the qualities of low-fat yogurt were investigated, expecting to obtain healthier and even more excellent quality low-fat yogurt by applying a new method. First, emulsion gel microparticles were prepared, and then particle size distribution of emulsion gel and water holding capacity (WHC), textural properties, rheological properties, microstructure, storage stability, and sensory evaluation of yogurt were carried out. The results showed that yogurt with emulsion gel had significantly superior qualities than yogurt made with skim milk powder, with better WHC, textural properties, rheological properties, and storage stability. The average particle size of whey protein-vegetable oil emulsion gel microparticles was significantly larger than that of whey protein-milk fat emulsion gel microparticles, and the larger particle size affected the structural stability of yogurt. The WHC of yogurt made with whey protein-vegetable oil emulsion gel microparticles (V-EY) was lower (40.41%) than that of yogurt made with whey protein-milk fat emulsion gel microparticles (M-EY; 42.81%), and the texture results also showed that the hardness, consistency, and viscosity index of V-EY were inferior to these of M-EY, whereas no significant differences were found in the cohesiveness. Interestingly, the microstructure of V-EY was relatively flatter, with more and finer network branching. The whey separation between V-EY and M-EY also did not show significant differences during the 14 d of storage. Compared with yogurt made with whey protein, vegetable oil, and skim milk powder, the structure of V-EY remained relatively stable and had no cracks after 14 d of storage. The sensory evaluation results found that the total score of V-EY (62) was only lower than M-EY (65) and significantly higher than that of yogurt made with skim milk powder. The emulsion gel addition improved the sensory qualities of yogurt. Whey protein emulsion gel microparticles prepared from vegetable oil can be applied to low-fat yogurt to replace fat and improve texture and sensory defects associated with fat reduction.

Gelling Characteristics of Emulsions Prepared with Modified Whey Protein by Multiple-Frequency Divergent Ultrasound at Different Ultrasonic Power and Frequency Mode.

The effect of ultrasonic frequency mode (mono, dual and tri-frequency) and ultrasonic power (0–300 W) on structural properties (intrinsic fluorescence and sulfhydryl content) of whey protein was studied. Emulsions prepared with modified whey protein were used to form the heat-set gels, and the properties of whey protein emulsion gels (WPEG) and their digestion were investigated. The textural and rheological properties of WPEG prepared using whey protein pretreated by mono and dual-frequency ultrasound at the power between 180–240 W were enhanced, while those of WPEG prepared with whey protein pretreated by triple-frequency above the power of 180 W were declined. WPEG prepared using whey protein pretreated by dual-frequency ultrasound (DFU) with the power of 240 W had the highest hardness and storage modulus which were 3.07 and 1.41 times higher than the control. The microstructure of WPEG prepared using DFU pretreated whey protein showed homogeneous and denser networks than those of the control according to the results of confocal laser scanning microscope (CLSM). The modification in the microstructure and properties of the WPEG prepared using DFU pretreated whey protein delayed the protein disintegration during the first 30 min of gastric digestion when compared with control. Whereas the release rate of free amino group of the WPEG prepared using whey protein modified by ultrasonic pretreatment increased during the intestinal phase when compared with that of control. The results indicated that using dual-frequency ultrasound to modify whey protein is more efficient in improving the properties of WPEG, and ultrasonic power should be considered during the application of ultrasound pretreatment in producing protein gels. The fine network of WPEG prepared with whey protein pretreated by ultrasound resulted in better hardness and storage modulus. Partially unfolding of the protein induced by ultrasound pretreatment might make the whey protein more susceptible to the digestive enzyme. Our results could provide new insights for using ultrasound as the potential processing tool on designing specific protein emulsion gels as the delivery system for nutrients.

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

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.

Characterisation of a thermally denatured whey protein isolate–butter emulsion/emulsion gel mediated by citric acid and a pre‐emulsification method

In this study, we prepared a cold‐set whey protein emulsion gel that was mediated by citric acid and a pre‐emulsification method. A pre‐emulsified solution was prepared with thermally denatured whey protein and butter. The stability and rheological properties of the emulsion gel were examined. The results demonstrated that the system changed from liquid behaviour at low protein contents to emulsion gel behaviour at high protein contents. Moreover, this method could produce a stable emulsion gel and its properties could be modulated by altering the protein and fat contents.

Effect of Gel Structure on the In Vitro Gastrointestinal Digestion Behaviour of Whey Protein Emulsion Gels and the Bioaccessibility of Capsaicinoids.

This study investigated the effect of gel structure on the digestion of heat-set whey protein emulsion gels containing capsaicinoids (CAP), including the bioaccessibility of CAP. Upon heat treatment at 90 °C, whey protein emulsion gels containing CAP (10 wt% whey protein isolate, 20 wt% soybean oil, 0.02 wt% CAP) with different structures and gel mechanical strengths were formed by varying ionic strength. The hard gel (i.e., oil droplet size d4,3 ~ 0.5 μm, 200 mM NaCl), with compact particulate gel structure, led to slower disintegration of the gel particles and slower hydrolysis of the whey proteins during gastric digestion compared with the soft gel (i.e., d4,3 ~ 0.5 μm, 10 mM NaCl). The oil droplets started to coalesce after 60 min of gastric digestion in the soft gel, whereas minor oil droplet coalescence was observed for the hard gel at the end of the gastric digestion. In general, during intestinal digestion, the gastric digesta from the hard gel was disintegrated more slowly than that from the soft gel. A power-law fit between the bioaccessibility of CAP (Y) and the extent of lipid digestion (X) was established: Y = 49.2 × (X − 305.3)0.104, with R2 = 0.84. A greater extent of lipid digestion would lead to greater release of CAP from the food matrix; also, more lipolytic products would be produced and would participate in micelle formation, which would help to solubilize the released CAP and therefore result in their higher bioaccessibility.

In-mouth breakdown behaviour and sensory perception of emulsion gels containing active or inactive filler particles loaded with capsaicinoids

This work investigated the effects of active versus inactive filler particles on the structure, rheological properties, in vivo oral breakdown behaviour and sensory perception of emulsion gels containing capsaicinoids (CAPs). CAP-loaded Tween-80-coated emulsion droplets were not bound with the whey protein matrix (i.e. emulsion gels containing inactive filler particles) and appeared to be flocculated and inhomogeneously distributed in the gel matrix, which led to drastically decreased mechanical gel strength. CAP-loaded Tween 80 emulsion gels had significantly lower fracture stress and fracture stain than CAP-loaded whey protein emulsion gels (emulsion gels containing active filler particles), indicating that they were more easily broken down into small fragments in the mouth at small deformations with less chewing (i.e. lower fracture energy, fewer chewing cycles and shorter duration). During mastication, large amounts of oil droplets were released from the gel matrix of the CAP-loaded Tween 80 emulsion gels, which also contributed to their significantly smaller bolus particle size. The released oil droplets from the CAP-loaded Tween 80 emulsion gels facilitated bolus formation through lubrication and decreased the chewing cycles. A higher degree of fragmentation led to greater surface exposure (i.e. new surface area created) during mastication, and therefore to higher mouth burn perception. The large amounts of oil droplets released from the gel matrix during mastication and the inhomogeneous distribution of the oil droplets because of flocculation of the CAP-loaded Tween 80 emulsion gels also contributed to their higher mouth burn perception. The oral processing behaviour of the CAP-loaded emulsion gels and the sensory perception of capsaicinoids could be tuned by manipulating the droplet-matrix interactions and the gel structure.

Characterization of β-carotene loaded emulsion gels containing denatured and native whey protein

The current study developed whey protein emulsion gels containing β-carotene, and the effects of the content of denatured protein and native protein were investigated. Two sets of emulsion gels were obtained by fixing the total protein content or the denature protein content (Cprotein-D). Emulsion properties were mostly affected by the content of native protein (Cprotein-N), and higher Cprotein-N resulted in emulsions with smaller particle size, higher surface charge and better creaming stability. Emulsions were then gelled with the addition of Glucono-δ-lactone. At fixed total protein content, higher Cprotein-D contributed to gels with higher mechanical properties, e.g., fracture stress, Young's modulus and storage modulus (G′). At fixed Cprotein-D, the increase in Cprotein-N also resulted in stronger gels but at much lower magnitude. The dynamic gelation analysis revealed that the increase in Cprotein-N or Cprotein-D resulted in shorter gelling time. All the gels had rather high water holding capacity, and the gels with greater mechanical strength had lower swelling ratios. When emulsion gels were applied as carriers for β-carotene, both Cprotein-D and Cprotein-N had significant effects on the light stability and heat stability of β-carotene.

Structure, rheology and functionality of whey protein emulsion gels: Effects of double cross-linking with transglutaminase and calcium ions

This article focused on the formation, physicochemical properties, and functionality of whey protein isolate (WPI) emulsion gels induced by crosslinking with transglutaminase and/or Ca2+ ions. The emulsion gels were fabricated using the combination of high-energy homogenization and cold-gelation. The microstructure, rheology and processing characteristics of the emulsion gels were then evaluated. Cross-linking with transglutaminase led to the formation of emulsion gels containing small particle aggregates, whereas cross-linking with Ca2+ led to the formation of larger particle aggregates. As expected, the apparent viscosity, strength, water holding capacity and hardness of the emulsion gels increased after crosslinking, especially when transglutaminase and Ca2+ ions were added together. Moreover, WPI hydrogels had higher gel strength in the presence of oil droplets than in their absence, suggesting that the droplets reinforced the gel structure. FTIR confirmed that the crosslinking agents promoted the aggregation of the proteins, thus forming an emulsion gel network. The results of this study may facilitate the design of new food materials with novel or improved textural and sensory characteristics.

Rheological, structural, and microstructural properties of ethanol induced cold-set whey protein emulsion gels: Effect of oil content

The aim of this research was to prepare ethanol-induced cold-set emulsion gels contain different content of oil and to investigate the effect on the rheological, textural, and microstructural properties. The results showed that the gelation rate, gel strength, water-holding capacity (WHC), and hardness of the ethanol-set emulsion gels improved as the content of oil increased. Rheological analysis showed that the emulsion gels changed from combined polymer/particle gel behavior at low oil contents to particle gel behavior at high oil contents. The emulsion gels contained a three-dimensional network of aggregated oil droplets at high oil contents, while they contained an even distribution of isolated droplets at lower oil contents. The results showed that the properties of the ethanol-set emulsion gels could be modulated by altering the oil content because the oil droplets acted as active fillers. Ethanol-induced gelation presents an intriguing possibility for encapsulation of alcohol-soluble, lipid-soluble and heat-labile bioactive compounds.

Structure of whey protein emulsion gels containing capsaicinoids: Impact on in-mouth breakdown behaviour and sensory perception

This work investigated the sensory perception of whey protein emulsion gels containing capsaicinoids, in relation to their structure and in-mouth breakdown behaviour. The gel structure was modified by varying the oil droplet size and the ionic strength. Eighteen human subjects were used to investigate oral processing behaviour and sensory perception. The gels were classified into three groups according to their rheological properties: semi-solid gel (10 mM NaCl with d4,3 of ∼0.17 μm); soft and elastic gels (10 mM NaCl with d4,3 of ∼4, 1 and 0.5 μm); hard and brittle gels (100 mM NaCl with d4,3 of ∼4, 1, 0.5 and 0.17 μm). A power-law relationship between gel hardness and masticated bolus particle size was established: Y=25.38X−0.29, with R2 = 0.69, indicating that greater hardness led to smaller bolus particle size. A power-law relationship between mouth burn perception and bolus particle size was also established: Y=119.5X−0.25, with R2 = 0.76, indicating that mouth burn perception was positively related to the degree of fragmentation. A higher degree of fragmentation led to greater surface exposure during mastication and, therefore, a greater possibility of capsaicinoid molecules being released. Moreover, an increase in gel hardness led to a lower diffusion rate of capsaicinoid molecules through the gelled particles and, therefore, to lower mouth burn perception. The effects of oil droplet release after mastication and saltiness perception were less important than the degree of fragmentation and gel hardness.

Effect of ultrasound pretreatment with mono-frequency and simultaneous dual frequency on the mechanical properties and microstructure of whey protein emulsion gels

The effect of ultrasound pretreatment with mono-frequency ultrasound (MFU) and simultaneous dual frequency (SDFU) on rheology, texture, water holding capacity (WHC) and microstructure of whey protein emulsion gels was investigated. Also, the protein structure was displayed using circular dichroism and fluorescence spectrum. The Results showed that ultrasound could improve mechanical properties and change the microstructure of whey protein emulsion gel compared with the control. It was also found that, ultrasound could lead to decreasing in α-helix and increasing in random coil thereby exposing more tryptophan residues. As storage modulus (G'), texture hardness and WHC were negatively correlated with α-helix content, however, they had positive correlation with random coil content. Simultaneous dual frequency ultrasound exhibited the highest effect among the ultrasound pretreatments. It was indicated that the composite of oil droplet particulate aggregate network and protein aggregate network in the microstructure of emulsion gel might have resulted from enhanced molecular interactions of protein by ultrasound pretreatment. In conclusion, the dual frequency ultrasound was effective in improving the mechanical properties of whey emulsion gel when compared with the mono-frequency ultrasound.

Role of gel structure in controlling in vitro intestinal lipid digestion in whey protein emulsion gels

The impact of gel structure and rheology on the intestinal digestion of canola oil dispersed within oil-in-water emulsions gelled with whey protein isolate (WPI) was investigated. Four heat-set WPI-stabilized emulsion gels were formed using NaCl and CaCl2. The gels were characterized by microscopy, rheology, fluorescence cross-correlation, diffusion measurements and swelling tests. Free fatty acid release during in vitro intestinal digestion was monitored using a pH-stat titrator and modelled using the Weibull function. Generally, gel strength as well as the proportion of embedded oil droplets increased at higher salt concentrations. Gels made with lower salt concentrations were softer and microstructurally homogeneous, and broke down more rapidly leading to a higher rate of lipid digestion. With the firmer gels, digestion was delayed by the denser, more spatially heterogeneous protein matrix. Overall, the manipulation of gel strength and microstructure modified the extent and rate of lipid digestion in WPI-stabilized oil-in-water emulsion gels, which may serve as the basis for the development of emulsion-based processed foods for applications related to controlled release of nutrients or bioactive compounds.