Wheat gluten-stabilized high internal phase emulsions as mayonnaise replacers

Prolamin-based complexes: Structure design and food-related applications

Prolamins are a group of safe food additives that are biocompatible, biodegradable, and sustainable. Zein, gliadin, kafirin, and hordein are common prolamins that have been extensively studied, particularly as these form colloidal particles because of their amphiphilic properties. Prolamin-based binary/ternary complexes, which have stable physicochemical properties and superior functionality, are formed by combining prolamins with polysaccharides, polyphenols, water-soluble proteins, and surfactants. Although the combination of prolamins with other components has received attention, the relationship between the structural design of prolamin-based complexes and their functionalities remains uncertain. This review discusses the production methods of prolamin-based complexes, the factors influencing their structural characteristics, and their applications in the food industry. Further studies are needed to elucidate the structure-function relationships between prolamins and other biopolymers, as well as the toxicological effects of these complexes in food.

Concentrated O/W emulsions formulated by binary and ternary mixtures of sodium caseinate, xanthan and guar gums: rheological properties, microstructure, and stability

The effects of xanthan gum (XG) (0, 0.3, 0.6 wt%), guar gum (GG) (0, 0.3, 0.6 wt%) and XG:GG mixtures (0.3-0.3, 0.3-0.6, 0.6-0.3 and 0.6-0.6 wt%) on the physical stability of sodium caseinate (CN) stabilized concentrated O/W emulsions (φoil = 0.6) were examined. The emulsion stability, microstructure, droplets size distribution, and rheological properties were evaluated. The findings showed that with increasing total gum concentration up to 0.6% droplets size and emulsion instability significantly decreased (p < 0.05). The emulsion containing a ternary mixture of CN:XG:GG at total gum concentration (0.6%) with a mixing ratio of 0.3:0.3 XG:GG exhibited the best stability with the highest ESI value (98.3%). Above the critical concentration, an excessive increase in storage modulus led to a significant increase in droplet size and emulsion instability. In brief, concentrated emulsions stabilized by binary and ternary mixtures (CN/XG/GG) may be applicable in special food like heavy cream and as a template for fabricating oleogels.

Heat stability of emulsions using functionalized milk protein concentrate generated by supercritical fluid extrusion

In this study, thermostable oil-in-water emulsions containing high protein contents were developed using milk protein concentrate (MPC) that was functionalized by supercritical fluid extrusion (SCFX) processing at low temperature and shear. Functionalized MPC (f-MPC) emulsions (3% protein-80% oil and 10% protein-50% oil) were compared with emulsions stabilized by commercial MPC (c-MPC), sodium caseinate (NaCas), and a commercial mayonnaise for their emulsifying properties and heat stability at 70 and 90 °C for 30 min, and 121 °C for 15 min. Zeta-potentials and interfacial protein concentrations of f-MPC emulsions were higher than that of c-MPC emulsions. f-MPC emulsions remained stable against creaming for at least 8 weeks at room temperature (23 °C), while their c-MPC counterparts showed significant creaming at the same conditions. Even after heating at 121 °C for 15 min, f-MPC emulsions retained their structural integrity as observed from their confocal images, droplet size distributions, and viscosities. In contrast, c-MPC emulsions and mayonnaise disintegrated upon heating at 121 °C for 15 min, and oil droplets of mayonnaise partially coalesced during heating at 90 °C for 30 min. f-MPC emulsions revealed higher viscosities compared to c-MPC emulsions, providing them improved stability. Viscosities of f-MPC emulsions were not significantly affected by heating at 90 °C for 30 min, while other emulsions exhibited a substantial increase in their viscosities due to protein denaturation and aggregation. Thus, f-MPC emulsions can be utilized in the development of protein-enriched functional foods (e.g., spreads) that are stable against high heat treatments.

Gliadin Nanoparticles Pickering Emulgels for β-Carotene Delivery: Effect of Particle Concentration on the Stability and Bioaccessibility

β-carotene is a promising natural active ingredient for optimum human health. However, the insolubility in water, low oral bioavailability, and instability in oxygen, heat, and light are key factors to limit its application as incorporation into functional foods. Therefore, gliadin nanoparticles (GNPs) Pickering emulgels were chosen as food-grade β-carotene delivery systems. The objectives of the present study were to investigate the influence of GNPs concentration on the rheological properties, stability, and simulated gastrointestinal fate of β-carotene of Pickering emulgels. The formulations of Pickering emulgels at low GNPs concentration had better fluidity, whereas at high GNPs concentration, they had stronger gel structures. Furthermore, the thermal stability of β-carotene loaded in Pickering emulgels after two pasteurization treatments was significantly improved with the increase of GNPs concentration. The Pickering emulgels stabilized with higher GNPs concentration could improve the protection and bioaccessibility of β-carotene after different storage conditions. This study demonstrated the tremendous potential of GNPs Pickering emulgels to carry β-carotene.

Deciphering the Structural Network That Confers Stability to High Internal Phase Pickering Emulsions by Cross-Linked Soy Protein Microgels and Their In Vitro Digestion Profiles

High internal phase Pickering emulsions (HIPPEs) stabilized by food-grade particles have received much attention in recent years. However, the stabilizing mechanism (e.g., structural network) in the continuous phase of HIPPEs stabilized by proteins is not well understood. In this work, we deciphered the stabilizing mechanisms that confer stability to HIPPEs produced from sunflower oil and soy protein microgels (SPMs). HIPPEs were fabricated at the protein concentrations of 1.50-2.00 wt % and oil volume fraction of 0.78-0.82. The cryo-scanning electron microscopy (cryo-SEM) observations indicated that there were two possible stabilizing mechanisms for HIPPEs at the protein concentrations of 1.50-2.00 wt %: the first is a stabilization provided by the shared monolayer of SPMs (at a protein concentration of 1.50%), and the other is stabilization provided by the distinct monolayer of SPMs (at protein concentrations of 1.75 and 2.00 wt %). The latter protein concentration created a thick network, formed by interacting SPMs, which trapped oil droplets. Results also confirmed that HIPPEs have an open-cell porous structure, forming a sponge-like morphology, where the internal phase was located. This study also investigated the digestibility of HIPPEs, suggesting a slower free fatty acid-releasing profile in in vitro intestinal digestion.

Synergistic enhancement of loading contents and chemical stability of lycopene distributing both inside and on the oil/water interface

Loading contents and chemical stability of lycopene were synergistically enhanced after dispersion in genipin-crosslinked-chitosan (CS) stabilized high internal phase emulsions (HIPEs). HIPEs could be prepared with the parameters for the emulsifiers of CS concentration from 0.5 to 5 mg/mL, pH value from 5.5 to 7.5, and CS/genipin mass ratio from 2:1 to 20:1. High loading content of lycopene, up to 0.25 wt% was achieved, with emulsifier in the final system only 1 mg/mL. As the loading contents were elevated, increasing amount of lycopene distributed in HIPEs in the form of insoluble crystals. Meanwhile, density of oil droplets decreased and the shape changed from polygon to sphere, which is supposed to be related to the interaction between the crystal and the oil-water interface. Stability of lycopene against ultraviolet, temperature, hydrogen peroxide, and iron ions was improved significantly, which could be ascribed to the layer of genipin-crosslinked-CS on oil droplet surface and the crystal status of lycopene. The storage stability of lycopene was improved tremendously after encapsulation by HIPEs. PRACTICAL APPLICATION: Low loading content of lycopene in emulsion systems is not conducive to the evaluation of its biological function in subsequent experiments, as well as their real application in food industry. It is also crucial to improve the stability of lycopene for the practical application in food industry. In this work, the loading content in delivery system and the chemical stability of lycopene are improved through encapsulation with high internal phase emulsions (HIPEs). The significance of these results may have implications in fields spanning from colloidal science to functional foods applications.

Ultrasound pre-fractured casein and in-situ formation of high internal phase emulsions

Traditional preparation of protein particles is usually complex and tedious, which is a major issue in the development of Pickering high internal phase emulsions (HIPEs). In this study, a facile and in-situ method for the preparation of food-grade Pickering HIPEs was developed using ultrasound pre-fractured casein flocs. The ultrasonic-treated casein protein and resulting Pickering HIPEs were characterised using particle size distribution, confocal laser scanning microscopy (CLSM), cryo-SEM, and rheological measurement. The results indicated that pH values of casein and ultrasonic power level were key parameters for casein protein dispersion into nanoparticles to form o/w Pickering HIPEs. In optimal conditions, the hexagons of emulsion droplets were close together, and the emulsions formed with ultrasonic caseins exhibited gel-like behaviour. Additionally, ultrasonic microscale-sized caseins (about 25 μm) disappeared upon the use of high speed homogenisation during the formation of HIPEs, while the chemical distribution revealed by confocal laser scanning microscopy indicated that the dispersive nanoparticles from casein proteins were evidently absorbed on the interface of HIPEs (cryo-SEM). These findings prove that ultrasound is an effective tool to loosen casein flocs to induce the in-situ formation of stabilised Pickering HIPEs. Overall, this work provides a green and facile route to convert edible oil into a soft solid, which has great potential for applications in biomedical materials, 3D printing technology, and various cosmetics.

Emulsifying properties of defatted rice bran concentrates enriched in fiber and proteins

BACKGROUND

Rice bran (RB), a by-product of the rice milling industry, constitutes around 10% of the total weight of rough rice. The interest in the use of RB is centered on its nutritional quality, its low cost, and its extensive worldwide production. As RB is commonly used for oil extraction, the defatted rice bran (DRB) is obtained as a second by-product. The aim of this work was to obtain a defatted rice bran concentrate (DRBC), enriched in protein and fiber, from defatted rice bran flour (DRBF) and to determine its physicochemical and emulsifying properties.

RESULTS

To obtain the DRBC, the starch was efficiently hydrolyzed (> 98%) with α-amylase and amyloglucosidase, with a concomitant increase in the proportions of crude protein (from 154.7 to 274.3 g kg^-1 ) and total dietary fiber (from 276.1 to 492.3 g kg^-1 ). Defatted rice bran concentrate exhibited a loss of protein solubility and increased surface hydrophobicity compared with DRBF. Defatted rice-bran concentrate dispersions with and without previous ultrasound treatment were prepared. The sonication led to an increase in the apparent viscosity. Emulsions were prepared with dispersions with and without previous ultrasound treatment and showed high stability in quiescent conditions over 28 days. However, the emulsions prepared with dispersions treated with ultrasound resulted in lower D_4,3 values and higher elastic and viscous moduli.

CONCLUSION

The rice bran concentrate can be used to obtain stable oil-in-water (O/W) emulsions, including both soluble and insoluble fractions, in acidic and neutral conditions. These innovative findings thus contribute to increasing the added value of this important by-product of the rice-milling industry. © 2019 Society of Chemical Industry.

Gelatin Hydrolysate Hybrid Nanoparticles as Soft Edible Pickering Stabilizers for Oil-In-Water Emulsions

The aim of this study was to fabricate edible gelatin enzymic digest (GED) based gel particles that can stabilize oil-in-water (O/W) microemulsions. The gel particles were generated by covalent crosslinking, with genipin, the individual protein molecules within tannic acid-induced gelatin hydrolysate (GED-TA) particles. The ability of the genipin-treated GED-TA (GP-GED-TA) to stabilize emulsions was evaluated by Turbiscan analysis and droplet-size changes. For comparison, gelatin hydrolysate (GE) and tannic acid-induced gelatin hydrolysate particles (GED-TA) were used as controls. The mean diameters of GED, GED-TA, and GP-GED-TA particles were 0.68 ± 0.1 nm, 66.2 ± 8.4 nm, and 66.9 ± 7.2 nm, respectively. Nanomechanic analysis using atomic force microscopy(AFM) indicated the average Young’s modulu of the GP-GED-TA particles was 760.8 ± 112.0 Mpa, indicating the GP-GED-TA were soft particles. The Turbiscan stability indexes (lower values indicate a more stable emulsion) of the emulsions stabilized with GED, GED-TA, and GP-GED-TA, after storage for three days, were 28.6 ± 1.5, 19.3 ± 4.8, and 4.4 ± 1.3, respectively. After one, or 60 days of storage, the volume-weighted mean diameters (D_[4,3]) of oil droplets stabilized by GP-GED-TA were 1.19 ± 0.11 μm and 1.18 ± 0.1 µm, respectively. The D_[4,3] of oil droplets stabilized by GED-TA, however, increased from 108.3 ± 5.1 μm to 164.3 ± 19.1 μm during the storage. Overall, the GP-GED-TA gel particles have considerable potential for stabilization of O/W emulsions in food products.

Fabrication of OSA Starch/Chitosan Polysaccharide-Based High Internal Phase Emulsion via Altering Interfacial Behaviors

This paper attempted to construct a high internal phase emulsion (HIPE) through altering interfacial behaviors using the electrostatic interaction between positive chitosan and negative octenyl succinic anhydride (OSA) starch. The partial polysaccharide complex of OSA starch/chitosan was used to stabilize HIPE, which was able to adsorb at the oil droplet interface and prevent the coalescence of oil droplets. The wettability of OSA starch was enhanced with the addition of positively charged chitosan, leading to the formation of partial complexes. The impact of pH and concentration of chitosan on the droplet size, surface charge, and interface behavior were investigated, and the formation of the polysaccharide complex was further confirmed by atomic force microscopy. The presence of the OSA starch/chitosan complex facilitated the formation of stable HIPE with a gel-like structure and satisfactory centrifugal and oxidative stability. These results are useful to provide information for fabricating polysaccharide-based HIPE delivery systems, which may help expand their application in the food industry.

Challenges and approaches for production of a healthy and functional mayonnaise sauce

Mayonnaise is a semisolid oil-in-water (O/W) emulsion which is made through the careful blending of oil, vinegar, egg yolk, and spices (especially mustard). In addition, mayonnaise traditionally contains 70%-80% oil, and egg yolk is a key ingredient contributing to its stability. Despite concerns about high cholesterol level in egg yolk, it is yet the most widely utilized emulsifying agent owing to its high emulsifying capacity. Today, the public knowledge about diet and health has been incremented, compelling the people to consume foodstuffs containing functional features. Thus, consumers, aware of the considerable influence of the diet on their health, demand nutritious and healthier food. Mayonnaise is usually cited by health-related issues due to its high cholesterol and fat content. Many researchers have tried to replace fat, as well as egg yolk completely or partially; however, low-fat mayonnaises require extra ingredients to keep the stability. In other words, each ingredient plays a specific role in textural and oxidative stability, and using alternative emulsifiers and fat replacers may affect the sensorial, textural, and antioxidant features of mayonnaise. Furthermore, mayonnaise, like other high-fat foodstuffs, is vulnerable to auto-oxidation. In addition to using fat replacers, mayonnaise is accompanied with bioactive ingredients to produce a healthy system. Therefore in this review, we gathered a quick summary of the ideas, including lowering the cholesterol and fat and using natural antioxidants, prebiotics, and probiotics in order to produce a healthy and functional mayonnaise sauce.

Salt reduction in liquid/semi-solid foods based on the mucopenetration ability of gum arabic

Gum arabic enhances the saltiness perception of liquid/semi-solid foods via a mucopenetration effect.

A stable high internal phase emulsion fabricated with OSA-modified starch: an improvement in β-carotene stability and bioaccessibility

A high internal phase emulsion (HIPE) was firstly fabricated with octenyl succinic anhydride modified starch through simple shear dispersion.

Fabrication of Zein/Pectin Hybrid Particle-Stabilized Pickering High Internal Phase Emulsions with Robust and Ordered Interface Architecture

Diets containing partially hydrogenated oils (PHOs) expose the human body to trans fatty acids, thus endangering cardiovascular health. Pickering high internal phase emulsions (HIPEs) is a promising alternative of PHOs. This work attempted to construct stable Pickering HIPEs by engineering interface architecture through manipulating the interfacial, self-assembly, and packing behavior of zein particles using the interaction between protein and pectin. Partially wettable zein/pectin hybrid particles (ZPHPs) with three-phase contact angles ranging from 84° to 87° were developed successfully. ZPHPs were irreversibly anchored at the oil-water interface, resulting in robust and ordered interfacial structure, evidenced by the combination of LB-SEM and CLSM. This situation helped to hold a percolating 3D oil droplet network, which facilitated the formation of Pickering HIPEs with viscoelasticity, excellent thixotropy (>91.0%), and storage stability. Curcumin in HIPEs was well protected from UV-induced degradation and endowed HIPEs with ideal oxidant stability. Fabricated Pickering HIPEs possess a charming application prospect in foods and the pharmaceutical industry.