Effect of ultrasonic power on the stability of low-molecular-weight oyster peptides functional-nutrition W1/O/W2 double emulsion

Influences of ultrasonic treatment on the physicochemical properties and microstructure of diacylglycerol-loaded emulsion stabilized with soybean protein isolate and sodium alginate

This study examined the impacts of ultrasonic power (0, 150, 300, 450, 600, and 750 W) and ultrasonic durations (3, 6, 9, 12, and 15 min) on the physicochemical properties and microstructure of diacylglycerol (DAG)-loaded emulsions stabilized with soybean protein isolate (SPI) and sodium alginate (SA). The findings indicated that the smallest particle size, zeta potential, and contact angle for SPI-SA-DAG emulsions were respectively 5.58 μm, -49.85 mV, and 48.65°, achieved at an ultrasonic power of 450 W. The emulsification properties, loss modulus, storage modulus, and apparent viscosity of the emulsions were optimal at this power setting and at a duration of 9 min. Analytical techniques, including confocal laser scanning-, scanning electron-, and atomic force microscopy, revealed that ultrasonication significantly altered emulsion aggregation state, with the surface roughness (Rq) being minimized at 450 W. These results demonstrated that the stability of SPI-SA-DAG emulsions can be effectively enhanced by an appropriate ultrasonic treatment at 450 W for 9 min. This research provides theoretical support for the broad application of sonication techniques in the food industry.

Improvement of physicochemical properties and quercetin delivery ability of fermentation-induced soy protein isolate emulsion gel processed by ultrasound

This study aimed to investigate the effects of ultrasonic treatment at different powers on the physicochemical properties, microstructure and quercetin delivery capacity of fermentation-induced soy protein isolate emulsion gel (FSEG). The FSEG was prepared by subjecting soy protein isolate (SPI) emulsion to ultrasonic treatment at various powers (0, 100, 200, 300, and 400 W), followed by lactic acid bacteria fermentation. Compared with the control group (0 W), the FSEG treated with ultrasound had higher hardness, water holding capacity (WHC) and rheological parameters. Particularly, at an ultrasonic power of 300 W, the FSEG had the highest hardness (101.69 ± 4.67 g) and WHC (75.20 ± 1.07%) (p < 0.05). Analysis of frequency sweep and strain scanning revealed that the storage modulus (G') and yield strains of FSEG increased after 300 W ultrasonic treatment. Additionally, the recovery rate after creep recovery test significantly increased from 18.70 ± 0.49% (0 W) to 58.05 ± 0.54% (300 W) (p < 0.05). Ultrasound treatment also resulted in an increased β-sheet content and the formation of a more compact micro-network structure. This led to a more uniform distribution of oil droplets and reduced mobility of water within the gel. Moreover, ultrasonic treatment significantly enhanced the encapsulation efficiency of quercetin in FSEG from 81.25 ± 0.62 % (0 W) to 90.04 ± 1.54% (300 W). The bioaccessibility of quercetin also increased significantly from 28.90 ± 0.40% (0 W) to 42.58 ± 1.60% (300 W) (p < 0.05). This study enriches the induction method of soy protein emulsion gels and provides some references for the preparation of fermented emulsion gels loaded with active substances.

Ultrasound treatment of crystalline oil-in-water emulsions stabilized by sodium caseinate: Impact on emulsion stability through altered crystallization behavior in the oil globules

Partial coalescence is a key factor contributing to the instability of crystalline oil-in-water emulsions in products like dressings and sauces, reducing shelf life. The intrinsic characteristics of semi-crystalline droplets, including solid fat content, fat crystal arrangement, and polymorphism, play a pivotal role in influencing partial coalescence, challenging prevention efforts even with emulsifiers like amphiphilic proteins. High-intensity ultrasound (HIU) has emerged as an efficient and cost-effective technology for manipulating bulk fat crystallization, thereby enhancing physical properties. This study specifically investigates the impact of HIU treatment on fat crystallization on protein-stabilized crystalline emulsions, utilizing palm olein stearin (POSt) as the lipid phase and sodium caseinate (NaCas) as the surfactant under various HIU powers (100, 150, 200, 300, and 400 W). Results show that increasing HIU power maintained the interfacial potential (-20 mV) provided by NaCas in the emulsions without significant differences. Higher HIU power induced the most stable polymorphic form (β) in the emulsions. Engagingly, the emulsions at 200 W exhibited better storage stability and slower partial coalescence kinetics. Semi-crystalline globules had more uniform and integral crystal clusters that were distributed tangentially near the droplet boundary, perhaps attributed to intermediate subcooling (40.4 °C) at 200 W. The acoustic energy of HIU significantly translates into thermal effects, influencing subcooling degrees as a dominant factor affecting crystallisation in the emulsions. This study establishes ultrasonic crystallization as a novel strategy for modifying the stability of emulsions containing fat crystals.

Preparation of housefly (Musca domestica) larvae protein hydrolysates: Influence of dual-sweeping-frequency ultrasound-assisted enzymatic hydrolysis on yield, antioxidative activity, functional and structural attributes

Dual-sweeping-frequency ultrasound (DSFU) was utilized in the preparation of polypeptides from housefly (Musca domestica) larvae protein (HLP). Results indicated that ultrasonication (20 ± 2/28 ± 2 kHz, 42 W/L, 25 min) significantly increased peptide yield and DPPH scavenging capacity by 8.25 % and 14.83 %, respectively. Solubility, foaming and emulsification properties of polypeptides were improved by 19.89 %, 33.33 % and 38.74 % over the control; along with notable reduction in particle size and increase in zeta potential. Tertiary structural changes of the sonicated hydrolysates were illustrated by UV and fluorescence spectra. FTIR showed that ultrasonication increased α-helix, β-turn, and random coil by 38.23 %, 46.35 % and 16.36 %, respectively, but decreased β-sheet by 48.03 %, indicating partial unfolding in HLP hydrolysate conformation and reduction in intermolecular interactions. The research results demonstrated that dual-sweeping-frequency ultrasonication has a great prospect in industry application for the purpose of improving enzymolysis efficiency and product quality for housefly larvae protein hydrolysates production.

An Updated Comprehensive Overview of Different Food Applications of W1/O/W2 and O1/W/O2 Double Emulsions

Double emulsions (DEs) present promising applications as alternatives to conventional emulsions in the pharmaceutical, cosmetic, and food industries. However, most review articles have focused on the formulation, preparation approaches, physical stability, and release profile of encapsulants based on DEs, particularly water-in-oil-in-water (W1/O/W2), with less attention paid to specific food applications. Therefore, this review offers updated detailed research advances in potential food applications of both W1/O/W2 and oil-in-water-in-oil (O1/W/O2) DEs over the past decade. To this end, various food-relevant applications of DEs in the fortification; preservation (antioxidant and antimicrobial targets); encapsulation of enzymes; delivery and protection of probiotics; color stability; the masking of unpleasant tastes and odors; the development of healthy foods with low levels of fat, sugar, and salt; and design of novel edible packaging are discussed and their functional properties and release characteristics during storage and digestion are highlighted.

Optimisation and characterization of double emulsion derived from rice starch, rice protein isolates and rice bran oil

This study focused on the development and evaluation of a stable emulsion system using rice starch, protein isolates, and bran oil as food ingredients. This was performed using a one-factor-at-a-time (OFAT) experimental strategy, which was subsequently refined using response surface modeling (RSM), and the emulsion was then characterized. The resulting quadratic polynomial model effectively captured all the responses, with regression coefficients exceeding 0.90. The emulsion activity index, emulsion stability index, and droplet size were 86.29 %, 93.44 %, and 100.59 nm, respectively. Turbidity was significantly influenced by particle size, with the double emulsion (sample B) exhibiting higher turbidity index (43,250.34 ± 0.046) than the reference sample (29,433.303 ± 0.018). The viscosity of the emulsion increased with the addition of the protein isolates. This inferred that a stable emulsion system derived from rice could serve a multifunctional purpose as carriers, fillers, and binders to enhance the physical, functional and sensory properties of foods.

Curcumin-loaded oil body emulsions prepared by an ultrasonic and pH-driven method: Fundamental properties, stability, and digestion characteristics

In this study, oil bodies (OBs) loaded with curcumin (Cur) were successfully prepared via an ultrasonic and pH-driven method. Ultrasonic treatment significantly improved the encapsulation efficiency (EE) and loading capacity (LC) of Cur, producing OB particles with small size, uniform distribution, and high ζ-potential absolute values. When the ultrasonic power was 200 W, the EE, LC, and ζ-potential absolute value were the greatest (88.27 %, 0.044 %, and -25.71 mV, respectively), and the OBs possessed the highest yellowness, representing the best treatment result. The confocal laser scanning microscopy (CLSM) and cryo-scanning electron microscopy (cryo-SEM) results was also intuitionally shown that. Moreover, circular dichroism (CD) proved that ultrasonic treatment could unfold the surface protein structure, further enhancing the stability. Therefore, the cream index (CI), peroxide value (POV), and thiobarbituric acid reactive substances (TBARS) were the lowest when the ultrasonic power was 200 W. In this case, the Cur loaded in OBs was well protected against hostile conditions, evidenced by the highest Cur retention rate and the lowest degradation rate constant. Finally, the in vitro gastrointestinal digestion simulation results showed that the ultrasonic treatment effectively increased the release of FFA, bioaccessibility, and stability of Cur, especially when the ultrasonic power was 200 W. This research offers a new OB-based delivery system to stabilize, deliver, and protect Cur for food processing.

Improvement of physicochemical properties, microstructure and stability of lotus root starch/xanthan gum stabilized emulsion by multi-frequency power ultrasound

Multi-frequency power ultrasound was applied as an environmentally friendly technique to control the nanoparticles (LS/XG-NPs) embedded with lotus root starch/xanthan gum, with the aim of enhancing the stability of Pickering emulsions. The present investigation was centered on evaluating the impact of ultrasound technology on various aspects of the emulsions, encompassing their mean particle size, particle size distribution, zeta potential, microstructure, rheological characteristics, and environmental stability. The findings of this study indicate that ultrasonic treatment enhanced the adsorption of LS/XG-NP onto oil droplets surface, resulting in a reduction in their size. Additionally, ultrasonic treatment decreased the viscosity and Brownian motion rate of the emulsion stabilized by LS/XG-NP, leading to increased fluidity. Furthermore, the emulsion's thermal stability and resistance to environmental oxidation were significantly enhanced through ultrasonic treatment. The Pickering emulsions that were prepared using ultrasound demonstrated excellent resistance to acid, alkali (pH 2-8) and salt ions (50-300 mM NaCl) for a period of 30 days during storage. It was worth anticipating that ultrasound-assisted LS/XG-NPs could efficiently retard the volatilization of fishy odor components within fish oil. Taken together, the present research has evinced the efficacy of ultrasound in enhancing the stability of Pickering emulsions coated with LS/XG-NPs. These findings offer significant novel insights into the advancement of ultrasound-assisted Pickering emulsions that are stabilized with starch-based or biopolymeric materials.