Construction of egg white protein particle and rhamnolipid based emulsion gels with β-sitosterol as gelation factor: The application in cookie

Study on the gelling properties of egg white/surfactant system by different heating intensities

The aim of this study was to elucidate the different effects and difference mechanism of gelling properties among egg white (EW) treated with different heating intensities and the composite addition of rhamnolipid and soybean lecithin. Particle size analyzer, potentiometric analyzer, surface hydrophobicity method, and Fourier transform infrared spectroscopy techniques were used to determine the physicochemical properties and molecular structure, respectively. Low-field nuclear magnetic resonance, magnetic resonance imaging, texture profile analysis, and scanning electron microscopy techniques were used to analyze the gelling properties and gel structure, respectively. And we illuminate the different mechanisms in the gelling properties of the EW with various treatments and key internal factors that play important roles in improving gelling properties by establishing the link between the gelling properties and relevant characteristics by mixed effects model and visual network analysis. The results indicate raising the content of rhamnolipid decreased the migration of immobilized water in the EW gel and the free water content. At the heating intensities of 55 °C/3.5, 65 °C/2.5, and 67 °C/1.5 min, with an increase in rhamnolipid, the gel's cohesiveness, gumminess, and chewiness gradually increased. The mixed effects model indicated that heating intensities and composite ratios have a 2-way interaction on zeta potential, the relaxation time of bound water (T21), the content of bound water (P21), the content of immobilized water (P22), and fractal dimension (df) attributes (P < 0.05). The visual network analysis showed that the protein solubility, the relaxation time of immobilized water (T22), surface hydrophobicity, zeta potential, average particle size (d43) and the relaxation time of free water (T23) are critical contributors to the different gelling properties of EW subjected to various treatments and the improvement of gelling properties. This study will provide theoretical guidance for the development of egg white products and the expansion of egg white's application scope in the egg product processing industry.

Rheology and stability mechanism of pH-responsive high internal phase emulsion constructed gel by pea protein and hydroxypropyl starch

There is an increasing demand for stable, highly viscoelastic, and printable emulsion gels based on pea protein (PeaP) as a substitute for animal fat. In this article, a simple pH modulation strategy was applied to regulate high internal phase (HIPE) gels prepared from PeaP and hydroxypropyl starch (HPS). The results showed that the interfacial tension of PeaP decreased from 11.9 to 7.1 mN/m at 5% PeaP and from 9.9 to 6.3 mN/m at 10% PeaP with increasing pH from 7 to 11. The incorporation of HPS improved the strength and physical stability of the HIPE gel. HIPE gels showed the best three-dimensional printing ability at pH 11. The main mechanism of HIPE gels at pH 3 was hydrophobic interaction, while electrostatic interaction dominated at pH 7, 9, and 11. This study may provide insights into the development of PeaP-based HIPE gels as a printable fat alternative.

Effect of the substitution of butter by double cross-linked egg yolk granules/sodium alginate emulsion gel on properties of baking dough during frozen storage

In this study, double cross-linked egg yolk granules (EYGs)/sodium alginate (SA) emulsion gel was constructed and used as butter substitute. The water binding capacity, rheology properties and microstructure of EYGs/SA emulsion gel showed that the network structure tended to be complete when the concentration of SA reached 1% (m/v). SA stabilized the EYGs/SA droplets and enhanced the spatial network structure of emulsion gel. After substitution for butter, the network structure of EYGs/SA emulsion gel with more water bounded and the polyhydroxy structure of SA molecules endowed dough with more water retention capacity. Meanwhile, the destruction of the microstructure of the replaced dough with EYGs/SA emulsion gel was significantly inhibited compared with the un-substituted dough after freezing. The baking ability results showed a satisfactory baking effect after substitution. Overall, this study provides a new avenue in the field of fat replacement and the application of EYGs/SA emulsion gels.

Composite formation of whey protein isolate and OSA starch for fabricating high internal phase emulsion: A comparative study at different pH and their application in biscuits

The composites formed by whey protein isolate (WPI) and octenyl succinate anhydride (OSA)-modified starch were characterized with a focus on the effect of pH, and their potential in fabricating high internal phase emulsions (HIPEs) as fat substitutes was evaluated. The particles obtained at pH 3.0, 6.0, 7.0, and 8.0 presented a nanosized distribution (122.04 ± 0.84 nm-163.24 ± 4.12 nm) while those prepared at pH 4.0 and 5.0 were remarkably larger. Results from the shielding agent reaction and Fourier transform infrared spectroscopy (FT-IR) showed that the interaction between WPI and OSA starch was mainly hydrophobic at pH 3.0-5.0, while there was a strong electrostatic repulsion at pH 6.0-8.0. A quartz crystal microbalance with dissipation (QCM-D) study showed that remarkably higher ΔD and lower Δf/n were observed at pH 3.0-5.0 after successive deposition of WPI and OSA starch, whereas slight changes were noted for those made at higher pH values. The WPI-OSA starch (W-O) composite-based HIPEs made at pH 3.0 and 6.0-8.0 were physically stable after long-term storage, thermal treatment, or centrifugation. Incorporation of HIPE into the biscuit formula yielded products with a desirable sensory quality.

Antibacterial Mechanism of Rhamnolipids against Bacillus cereus and Its Application in Fresh Wet Noodles

Bacillus cereus (B. cereus) is a common foodborne pathogen causing food poisoning incidents. This study aimed to evaluate the antibacterial activity and underlying mechanism of rhamnolipids (RLs) against B. cereus. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of RLs for B. cereus were determined to be 16.0 mg/L and 32.0 mg/L, respectively. Scanning electron microscopy and fluorescence microscope images, as well as data of membrane potential, relative electric conductivity, and leakage of intracellular components revealed that RLs disrupted the integrity of the cell membrane. Furthermore, the reactive oxygen species content, catalase (CAT) and superoxide dismutase (SOD) activity indicated that RLs activated the oxidative stress response of B. cereus in response to RLs. Fresh wet noodles (FWN) were used as a food model, and RLs showed a significant killing effect on B. cereus with a sustained inhibitory effect at the concentrations ranging from 128.0 to 1024.0 mg/kg. Additionally, RLs promoted the conversion of free water to bound water in FWN, which improved the storage of FWN and made the taste more resilient and chewy. These results suggest that RLs could be a potential alternative to antimicrobial agents and preservatives for applications in food processing.

Tailoring a novel ovalbumin emulsion gel for stability improvement and functional properties enhancement: Effect of oil phase structure changes by beeswax

This study aimed to form a novel emulsion gel (EG) through structured oil phase of natural component beeswax (BW), together with ovalbumin (OVA), and to investigate the mechanism of its formation and stabilization in terms of microstructure and processing properties. Confocal laser scanning microscopy (CLSM) demonstrated that the EG formed a continuous double network structure since the superior crystallinity of the oil phase was given by BW. Fourier transform infrared spectroscopy (FT-IR) illustrated that the acylation of the phenolic hydroxyl group in BW with an amide bond in OVA, increased the hydrogen bonding of EG. Furthermore, the immobilization of the oil phase results in better thermal and freeze-thaw stability of EG. Finally, EG was used as a curcumin delivery system, and the presence of BW significantly improved its adaptability to multiple environmental factors. In summary, our study would provide valuable ideas for developing the design of finely structured functional food.

Progress in the Application of Food-Grade Emulsions

The detailed investigation of food-grade emulsions, which possess considerable structural and functional advantages, remains ongoing to enhance our understanding of these dispersion systems and to expand their application scope. This work reviews the applications of food-grade emulsions on the dispersed phase, interface structure, and macroscopic scales; further, it discusses the corresponding factors of influence, the selection and design of food dispersion systems, and the expansion of their application scope. Specifically, applications on the dispersed-phase scale mainly include delivery by soft matter carriers and auxiliary extraction/separation, while applications on the scale of the interface structure involve biphasic systems for enzymatic catalysis and systems that can influence substance digestion/absorption, washing, and disinfection. Future research on these scales should therefore focus on surface-active substances, real interface structure compositions, and the design of interface layers with antioxidant properties. By contrast, applications on the macroscopic scale mainly include the design of soft materials for structured food, in addition to various material applications and other emerging uses. In this case, future research should focus on the interactions between emulsion systems and food ingredients, the effects of food process engineering, safety, nutrition, and metabolism. Considering the ongoing research in this field, we believe that this review will be useful for researchers aiming to explore the applications of food-grade emulsions.