Liquid Egg White Research Articles

Irradiation-Assisted Enhancement of Foaming and Thermal Gelation Functionality of Liquid Egg White.

Ionizing radiation has its unique popularity as a non-thermal decontamination technique treating with protein-rich foodstuffs to ensure the microbial and sensory quality, particularly for shell eggs. However, the changes in the functional properties of egg protein fractions such as liquid egg white (LEW) with macro/microstructural information are still controversial. Hence, this study was designed to elaborate the foaming and heat-set gelation functionality of LEW following different γ-ray irradiation dose treatments (0, 1, 3 or 5 kGy). For such, the physicochemical properties (active sulfhydryl and the hydrophobicity of protein moieties), structural characteristics (through X-ray diffraction, Fourier-transform infrared spectroscopy and differential scanning calorimetry) and interfacial activities (rheological viscosity, interfacial tension, microrheological performance) were investigated. Then, the thermal gelation of LEW in relation to the texture profile and microstructure (by means of a scanning electron microscope) was evaluated followed by the swelling potency analysis of LEW gel in enzyme-free simulated gastric juice. The results indicated that irradiation significantly increased the hydrophobicity of liquid egg white proteins (LEWPs) (p < 0.05) by exposing non-polar groups and the interfacial rearrangement from a β-sheet to linear and smaller crystal structure, leading to an enhanced foaming capacity. Microstructural analysis revealed that the higher dose irradiation (up to 5 kGy) could promote the proteins' oxidation of LEW alongside protein aggregates formed in the amorphous region, which favored heat-set gelation. As evidenced in microrheology, ≤3 kGy irradiation provided an improved viscoelastic interface film of LEW during gelatinization. Particularly, the LEW gel treated with 1 kGy irradiation had evident swelling resistance during the times of acidification at pH 1.2. These results gave new insight into the irradiation-assisted enhancement of foaming and heat-set gelation properties of LEW.

Endogenous reactive oxygen species (ROS)-driven protein oxidation regulates emulsifying and foaming properties of liquid egg white

Highly oxidative reactive oxygen species (ROS) attack protein structure and regulate its functional properties. The molecular structures and functional characteristics of egg white (EW) protein (EWP) during 28 d of aerobic or anaerobic storage were explored to investigate the “self-driven” oxidation mechanism of liquid EW mediated by endogenous ROS signaling. Results revealed a significant increase in turbidity during the storage process, accompanied by protein crosslinking aggregation. The ROS yield initially increased and then decreased, leading to a substantial increase in carbonyl groups and tyrosine content. The free sulfhydryl groups and molecular flexibility in EWP exhibited synchronicity with ROS production, reflecting the self-repairing ability of cysteine residues in EWP. Fourier-transform infrared spectroscopy indicated stable crosslinking between EWP molecules in the early oxidation stage. However, continuous ROS attacks accelerated EWP degradation. Compared with the control group, the aerobic-stimulated EWP showed a significant decrease in foaming capacity from 30.5 % to 9.6 %, whereas the anaerobic-stimulated EWP maintained normal levels. The emulsification performance exhibited an increasing-then-decreasing trend. In conclusion, ROS acted as the predominant factor causing deterioration of liquid EW, triggering moderate oxidation that enhanced the superior foaming and emulsifying properties of EWP, and excessive oxidation diminished the functional characteristics by affecting the molecular structure.

The Efficacy of Radiolabeling the Albumin in Egg Whites with 99mTc-Sulfur Colloid.

In 2009, the Society of Nuclear Medicine and Molecular Imaging published a standardized protocol guideline for gastric emptying scintigraphy that contains specific instructions on the exact meal and preparation procedure. Previous research has shown that the standardized meal and proper preparation of the meal for gastric emptying scintigraphy are not being adopted by some facilities. This research explores the differences of radiolabeling in the method of preparation of 99mTc-sulfur colloid (SC)-radiolabeled eggs. Methods: Liquid egg whites were mixed with 99mTc-SC before cooking in conjunction with the standardized protocol. A second sample set was prepared by adding the 99mTc-SC to eggs after they were cooked. Each sample set was placed in a solution of HCl and pepsin to simulate gestation. Radiolabeling efficacy was tested on each sample set at 2 and 4 h after gestating in HCl and pepsin. Results: 99mTc-SC added to the liquid egg whites before microwave cooking yielded radiolabeling efficacy of 70% 99mTc-SC after 2 and 4 h of simulated gastric fluid gestation. In contrast, radiolabeling after cooking the egg whites yielded 50% radiolabeling after simulated gestation. Conclusion: The results from this experiment showed that the method of mixing the 99mTc-SC with liquid egg whites before microwave cooking has higher binding efficacy than when adding 99mTc-SC onto already cooked egg whites. These results highlight the importance of following the standardized protocol for the meal preparation of a gastric emptying study.

An Evaluation of Gastric Emptying Scintigraphy Protocols in Health Care Institutions When Compared with the Society of Nuclear Medicine and Molecular Imaging Procedure Guidelines.

This study aimed to analyze the compliance of health care institutions with the Society of Nuclear Medicine and Molecular Imaging (SNMMI) procedure guidelines for gastric emptying scintigraphy (GES). Methods: A 19-question survey on demographics and the GES protocol was conducted using a Google form. The demographic questions covered position, number of technologists in the department, location, type of health care institution, and number of GES studies per month. The protocol questions included patient preparation, meal preparation, withholding of scheduled medications, radiopharmaceutical type, and radiopharmaceutical dose. The survey was sent to 7 nuclear medicine Facebook groups and a list of clinical affiliates provided by the Indiana University School of Medicine Nuclear Medicine Program. Descriptive statistics were compiled for most questions. A Fisher exact test with a significance level of 0.05 was used to compare the type of health care institution with compliance with the SNMMI GES protocol regarding radiolabeling time, meal preparation, and meal components, as well as to compare the type of health care institution with the number of GES studies performed per institution. Results: In total, 240 people responded to the survey. Most were nonsupervisory nuclear medicine technologists (72%) in nonacademic institutions (72%) and groups with 4 or more technologists (62%). Of the respondents, 72% followed the SNMMI guideline of adding the radiopharmaceutical before cooking, but only 37% followed the meal component guideline. There was no significant association between the type of institution or the number of GES studies and compliance with radiolabeling time or with meal preparation or components. Most respondents asked patients to withhold medications per SNMMI guidelines and used the recommended radiopharmaceutical (99mTc-sulfur colloid, 95%) at the recommended dose (18.5-37 MBq, 84%). Conclusion: Although most respondents followed most aspects of the SNMMI guidelines for GES, more than half did not use the recommended meal of liquid egg whites. Compliance did not vary between academic and nonacademic institutions or between groups performing a large or a small number of GES studies.

Characterization and Molecular Dynamics Simulation of a Lipase Capable of Improving the Functional Characteristics of an Egg-Yolk-Contaminated Liquid Egg White.

Lipase has great application potential in hydrolyzing residual yolk lipid in egg white liquid to restore its functional properties. In this study, a lipase gene from Bacillus subtilis was expressed in E. coli BL21 (DE3) and named Lip-IM. Results showed that although Lip-IM has stronger specificity for medium- and short-chain substrates than long-chain substrates (C16, C18), due to its excellent enzyme activity, it also has strong hydrolysis activity for long-chain substrates and maintained over 80% activity at 4-20 °C, but significantly reduced when the temperature exceeds 40 °C. The addition of 0.5% Lip-IM enhanced foaming ability by 26% (from 475 to 501%) and reduced liquid precipitation rate by 9% (from 57 to 48%). Furthermore, molecular dynamics (MD) simulations were run to investigate the conformational stability of Lip-IM at different temperatures. Results showed that Lip-IM maintained a stable conformation within the temperature range of 277-303 K. Fluctuations in the flexible area and backbone movement of proteins were identified as the main reasons for its poor thermal stability.

Enhancement of foaming properties and storage stability of pasteurized liquid egg white through ultrasound modification

Due to the high heat sensitivity of liquid egg white (LEW), there were a loss of foaming properties during pasteurization. At the same time, the temperature of pasteurization was limited by this property and did not limit the growth of microorganisms very well. Therefore, the article hoped to improve the foaming characteristics of pasteurized liquid egg white (PLEW) and to increase the stability during storage by using water-bath ultrasound. It was found that the foaming capacity of the pasteurization only group increased from 270% to 326% under optimal sonication conditions (60 Hz, 400 W, 15 min). The increase in protein solubility and decrease in particle size following ultrasound suggested that ultrasound had a deaggregation effect. The fact that surface tension was reduced suggested that sonication could provide more soluble proteins and a more flexible conformation for PLEW. Both free sulfhydryl and surface hydrophobicity were enhanced, which might be related to the disruption of protein molecular forces by the cavitation effect of ultrasound. The results of spectral analysis again revealed that the essence of ultrasound to improve the foaming properties of PLEW lied in changing the conformation of the protein molecule. Furthermore, the results also demonstrated that the ultrasound-treated LEW showed better foaming properties, minimal changes in viscosity, lower total volatile basic nitrogen content, and a longer shelf life (40 d) during storage. The quality of the ultrasound-treated group remained the most stable. Therefore, ultrasound has great potential for improving the foaming ability and stability of PLEW.

Investigation of the effects of reverse osmosis and ultrafiltration treatments on physicochemical, techno-functional, and rheological characteristics of liquid egg albumen and prepared meringue cookie batter

AbstractMembrane filtration has a promising advantage in the processing of egg products. In this study, liquid egg whites (LEW) were separately concentrated by using reverse osmosis (RO) and ultrafiltration (UF) techniques. The first aim of this research was to determine the effects of the concentration pre-treatments on the physico-chemical quality criteria (pH, relative whipping capacity, foaming stability, water holding capacity-WHC, colour) and the rheological behaviour (viscosity, oscillation) of LEW samples. The second aim of this research was to investigate the impact of the membrane pre-treatment on meringue's functional quality attributes such as meringue batter density and meringue batter colour values (L*, a*, b*). The average dry matter of LEW was increased from 12% to 23% by the concentration pre-treatment process (RO and UF), and water was removed from the LEW. In addition, the batter density of meringue cookie samples was 0.37 ± 0.01 g mL−1 in UF and RO. The differences between the pH and dry matter values of the ultrafiltration and reverse osmosis treated groups were found to be statistically similar, and it was observed that the elastic modulus (G′) increased with the increase in frequency in the rheological measurements. It has been determined that G′ is higher than G″ in all samples. An elastic/solid-like (G′ &gt; G″) structural behaviour was determined while increasing the frequency value. It was determined that the WHC of LEW treated with RO was higher than of the group treated with UF. The results of the study showed that while reducing transportation and storage costs, the water content of &gt;80% of LEW (raw material-the treated liquid egg white) removed by UF and RO applications can be suitable to produce meringue batter cookies (semi-finished product).

Analyses of Chemical and Physical Egg Quality Parameters of Laying Hens Housed in Different Conditions in Turkey

The aim of the present study is to determine the content of chemical and physical quality parameters of hen eggs (liquid whole egg (LWE), liquid egg yolk (LEY), and liquid egg white (LEW)) produced for different housing and feeding conditions in Turkey. Chemical quality parameters (protein, lipid, and moisture) and physical quality parameters (total soluble solid (°Brix), pH, conductivity, and yolk:white ratio) were analyzed using different egg samples. Kjeldahl, wet ashing, and oven-drying official methods were used for the protein, total lipid, and moisture analyses of egg samples. The highest protein content in the LEY and LEW samples were found to be 19.0% and 15.13%, respectively for the tenth sample having fortified feeding (selenium+DHA) parameters. For LWE samples, it was also obtained 15.65% with the second sample having a not fortified feeding parameter. The highest total lipid content for LWE samples was determined as 10.43% for the seventh sample which housed under cage free conditions and fed with organic (omega3+EPA+DHA) fortifiers, while it was found with a value 25.7% for the second and third LEY samples possessing a not fortified feeding parameters. The highest moisture content was determined as 78.37%, 54.64%, and 89.11 for thirty-first LWE sample (with not fortified feeding), third LEY sample (with not fortified feeding) and sixth LEW sample (having cage free and organic parameters), respectively. As a result, the minimum, average, and maximum contents of the chemical and physical quality parameters were determined for laying hen eggs raised in several housing and feeding conditions in Turkey.

Induction of viable but nonculturable Salmonella spp. in liquid eggs by mild heat and subsequent resuscitation

Salmonella spp. is one of the leading causes of foodborne outbreaks worldwide. Salmonella spp. has been associated with a variety of food sources, particularly egg products. They can enter a viable but nonculturable (VBNC) state in response to harsh stress. VBNC cells still retain membrane integrity and metabolic activity, which may pose health risks. However, the formation mechanism and resuscitation ability of VBNC cells are not well understood. In this work, Salmonella spp. cocktails, including Salmonella enterica serovar Newport and Salmonella enterica serovar Enteritidis, in liquid egg products was induced into a VBNC state by mild heat treatment, a commonly used method to inhibit the growth of pathogenic in liquid egg industry. Mild heat induced VBNC cells were found to resuscitate in liquid egg yolk (LEY) and liquid whole egg (LWE), but they failed to recover in liquid egg white (LEW). In addition, a certain number of cells remained as VBNC state after in vitro digestion. The membrane vesicle (MV) protein encoding gene pagC, two-component system encoding genes phoP/Q and sigma factor encoding gene rpoS were highly expressed in VBNC cells compared with the culturable counterparts. The results of this study can contribute to a better understanding of the health risks associated with Salmonella spp. in VBNC state and provide a theoretical basis for formation mechanism of VBNC state.

Pasteurization of egg white by integrating ultrasound and microwave: Effect on structure and functional properties

Microwave (MW) pasteurization is an efficient and energy saving technology, but it has the disadvantage of thermal inhomogeneity. This study reduced the inhomogeneity of pasteurization by integrating ultrasound and microwave (IUM) treatment, and decreased adverse effect on the functional properties of liquid egg white (LEW) while ensuring the pasteurization effect. The particle size increased by 48.5 nm after IUM treatment, indicating egg white protein was slightly denatured and aggregated. However, the secondary structure changed little. Compared with traditional pasteurized LEW, lower apparent viscosity, higher zeta potential value and hydrophobicity of LEW treated by IUM (IUM-LEW) made the functional properties maintained or improved. Emulsification capacity (EC), emulsification stability (ES) and gel strength of IUM-LEW were increased by 6.83%, 7.41% and 77 g, respectively. This study provided an alternative to traditional pasteurization for LEW.

The Quality Analysis and Deterioration Mechanism of Liquid Egg White during Storage

The quality of liquid egg white (LEW) during storage is critical for the development of the egg industry. In order to effectively control its storage quality, the effects of packaging materials and storage conditions on the quality of LEW were investigated. High-throughput sequencing (HTS) was applied to explore changes in bacterial population proportions and microflora in the spoilage of LEW. The shelf life of LEW packaged with glass (LEW-PG), plastic (LEW-PP), and tinplate (LEW-PT) was preliminarily determined to be 8, 5, and 7 days, respectively. LEW-PG possessed superior sensory scores (65) and L values (87.5), and a lower growth rate of total volatile basic nitrogen (TVB-N) content among the three samples on the last day of shelf life, and was chosen for further study. During 24 days of storage, the sensory scores of the LEW-PG in 10 °C and 4 °C groups decreased by 32.7% and 25.7%, respectively. There was no significant difference in foaming properties of LEW-PG between the 10 °C and 4 °C groups (p &gt; 0.05). HTS analysis showed that the abundance of species composition in the 10 °C samples was higher than that in the 4 °C samples, though the latter possessed a higher community diversity. At the genus level, the dominant bacteria in the 10 °C group were Pseudomonas (21.79%), others (19.21%), and Escherichia (11.21%), while others (37.5%), Escherichia (30.40%), and Bifidobacterium (17.72%) were highly abundant in the 4 °C samples. It is hoped that this study could provide theoretical support for quality control of LEW during storage.

Effects of guar gum or xanthan gum addition in conjunction with pasteurization on liquid egg white

In this study, effects of varying levels of xanthan or guar gum (XG/GG, 0.05%, 0.1%, 0.2%, 0.4% and 0.8%, w/v) on the spatial structure and functional properties of egg white (EW) proteins under different pasteurization conditions of the liquid egg was evaluated. Results showed that XG could bury the aromatic ring residues and reduce the hydrophobicity of protein in EW, whereas GG could only increase the hydrophobicity. With 0.8% GG addition and pasteurization under 60℃/3.5 min, the emulsifying stability of EW was improved by nearly 100%, while with 0.8% XG addition the gel structure of EWwould become porousandloosen under each pasteurization condition. The hardness of EW gels was decreased by 90% when the concentration of XG was 0.4% or 0.8%. According to the results, the concentration of gums and the pasteurization parameters should be considered together when adding gums into the liquid egg products for pasteurization simultaneously.

Improvement of Structural Characteristics for Liquid Egg White by Enzyme Treatment

ABSTRACT In this study, the functionality of liquid egg albumin pre-treated by protease was investigated to evaluate the storage stability mechanisms for field of gastronomy and gastronomist. This study aims to improve the physicochemical and functional properties such as relative whipping capacity (RWC), foam stability, color, pH, and turbidity by protease (0-control, 0.5, 1.0, and 1.5%-v/v). The protease enhanced RWC comparing to the untreated on day-0 and 27, while the control group showed lower RWC and higher values in 1% and 1.5% treatments. The effect of protease was more clearly apparent on turbidity with significantly decrease during storage (p < .05). The turbidity values ranged from 0.74 to –0.31. A considerable decrease was observed in color values of treated samples on day 27, while the best treatment was 1.0% in foam stability and 1.5% in RWC. Protease could be used in modified albumin to improve techno-functional characteristics of bakery products.

Analysis of thermal processing of liquid eggs using a high frequency ohmic heating: Experimental and computer simulation approaches

Experimental and simulated approaches combining an ohmic heating (OH) process and an external heating system for the pasteurization of liquid egg whites, yolks, and whole eggs were evaluated in this study. 3D computer simulation models were developed for each approach using COMSOL Multiphysics 5.6 to visualize the temperature and distribution of degrees of pasteurization at several cross sections. From both the hot and cold spots of the samples, the temperature, thermal protein non-denaturation ratio (X), and pasteurization profiles were estimated. Color changes were also evaluated using a computer vision system (CVS). The heating conditions were optimized according to a high constant X value, a low total color difference value (ΔE < 3), and certain pasteurization standards for each sample. OH treatment combined with concurrent external heating approaches reduced the process time and prevented local overheating. These results are of potential value for the design of ohmic pasteurization systems for liquid eggs.

Effects of protease-hydrolyzed egg white on the meringue batter properties and meringue textural and sensory properties during storage

This study was focused to analyze the effects of different concentrations (0.5, 1.0, 1.5 w/v) of protease hydrolyzed liquid egg white (LEW) on meringues batter and cookies. The color (L*, a*, b*, ΔE), physical and aeration properties (batter specific density (BSD), cooked meringues specific volume (MSV)), water activity, texture analysis and sensorial profiles of the meringues during three months of extended storage at ambient temperature (23 ± 2°C) was investigated. Additionally, the creep recovery compliance parameters, colors, and physico-chemical characteristics of freshly whipped meringue batter were also evaluated. Protease hydrolyzed samples exhibited higher L* and lower b* parameter. The BSD values (g/cm3) for control - 0 % (0.51 ± 0.01) was significantly decreased (p < 0.05) after enzymatic treatment, lower values obtained in 1 % (0.37 ± 0.01) and 1.5 % (0.35 ± 0.01). The MSV values of cooked meringue was significantly increased (p < 0.05) depends on the protease concentrations. The strength of the meringue batter is increased after hydrolysis. However, the enzymatic hydrolysis reduced consumer satisfaction. This research points out the optimum (1.0 %) hydrolyzed LEW in preparation of meringue improved functionality, such as BSD and MSV parameters.

Influence of the Initial Cell Number on the Growth Fitness of Salmonella Enteritidis in Raw and Pasteurized Liquid Whole Egg, Egg White, and Egg Yolk.

Salmonella growth in egg and egg products has been widely studied, but there are still some aspects that are not fully known. The objective of this work was to study the influence of the initial cell number on the growth fitness of Salmonella Enteritidis in raw and pasteurized egg products. Growth curves of five Salmonella Enteritidis strains in raw and pasteurized egg products, starting from different initial numbers, were obtained and fitted to the Baranyi and Roberts model. The results revealed that lower initial numbers led to longer lag phases (λ) and lower maximum specific growth rates (μmax) in raw liquid whole egg. Similar results were observed in raw egg white (except for one strain). Conversely, no influence (p > 0.05) of the initial concentration on Salmonella growth parameters in raw egg yolk was observed. On the other hand, no influence of the initial number of cells on Salmonella growth fitness in commercial pasteurized liquid whole egg was observed. The results obtained demonstrate that the disappearance of this initial-dose dependency phenomenon was dependent on the intensity of the thermal treatment applied. Finally, the influence of the initial number was, in general, lower in pasteurized than in raw egg white, but large differences among strains were observed.

Effectiveness of enzymes on structural, functional and creep-recovery behavior of freshly prepared meringue's batter using liquid egg albumen.

In this research, the impacts of varying concentration of phospholipase A2 (PLA), protease and lipase enzyme-treated liquid egg white (LEW) were prepared using meringue batters. The gelling physico-chemical, and rheological properties such as rheological creep-recovery compliance behavior, color value (L*, a*, b*, ∆E*, Chroma, Hue and WI), gelling strenght, pH value, gelling index as TPA parameter and specific density of freshly prepared meringue batter were analyzed. The specific density of meringue batter of control (0.49 ± 0.01) was significantly decreased (P < 0.05) after enzyme treatments of PLA (0.39 ± 0.01), lipase (0.33 ± 0.01), and protease (0.37 ± 0.01). Also, the enzymatic treatment significantly decreased the b* values from - 0.08 ± 0.07 to - 0.76 ± 0.04, - 0.70 ± 0.06, and - 0.73 ± 0.03, respectively. The Burgers model was used to characterize rheological behavior of enzyme treated and freshly prepared meringue samples. Creep-recovery responses of samples were satisfactory (R2 > 0.99) for evaluation of creep-recovery behavior. This research points out the efficacy of lipase pre-treated LEW in meringue preparation on improving functionality such as batter density and gelling properties.

Predictive Modeling for the Growth of Salmonella spp. in Liquid Egg White and Application of Scenario-Based Risk Estimation.

The objective of the study was to develop a predictive model of Salmonella spp. growth in pasteurized liquid egg white (LEW) and to estimate the salmonellosis risk using the baseline model and scenario analysis. Samples were inoculated with six strains of Salmonella, and bacterial growth was observed during storage at 10–37 °C. The primary models were developed using the Baranyi model for LEW. For the secondary models, the obtained specific growth rate (μmax) and lag phase duration were fitted to a square root model and Davey model, respectively, as functions of temperature (R2 ≥ 0.98). For μmax, the values were satisfied within an acceptable range (Af, Bf: 0.70–1.15). The probability of infection (Pinf) due to the consumption of LEW was zero in the baseline model. However, scenario analysis suggested possible salmonellosis for the consumption of LEW. Because Salmonella spp. proliferated much faster in LEW than in egg white (EW) during storage at 20 and 30 °C (p < 0.01), greater Pinf may be obtained for LEW when these products are stored at the same conditions. The developed predictive model can be applied to the risk management of Salmonella spp. along the food chain, including during product storage and distribution.

Effects of HHP’s Holding Time on Proteins of Liquid Egg Products

Today’s consumers require food products with fresh, or fresh-like characteristics. Minimal processing technologies are indicated as technologies with a gentle impact on sensorial and techno-functional properties. High Hydrostatic Pressure (HHP) is a widely used minimal technology considered as a cold pasteurization method in food preservation. The effect of applied pressure of HHP is well understood, but the holding time of HHP treatment is not extensively investigated in topic of proteins. One of the most important attribute of liquid egg products are the great foaming ability, foaming stability as well as emulsifying properties. These techno-functional properties are highly influenced by the protein structures of egg products. In our study, liquid egg products were pressurized at 400 MPa, for 1, 3, 5 7 and 10 minutes. The protein structures of liquid egg white (LEW), liquid egg yolk (LEY) and liquid whole egg (LWE) were investigated using Differential Scanning Calorimetry (DSC).Our study pointed out that after HHP treatment at 400 MPa, for 10 minutes 12% decrease in denaturation enthalpy of LWE was observed. In LEY 30% decrease was detected after 10 minutes HHP treatment. The highest impact of HHP treatment (35% decrease in denaturation enthalpy) in LWE was noted. The changes in protein structures of liquid egg products were smaller, than the effects of higher pressure applied for preservation. In aspects of techno-functional properties applying a longer holding time is more favourable, than applying a higher pressure.

Effect of ultrasound-irradiation combined pretreatment on the foamability of liquid egg white.

This study aims to optimize the ultrasound-irradiation combined pretreatment conditions to enhance the liquid egg white (LEW) foamability and investigate the changing mechanism about the physical and structural properties of LEW during the processing. Results indicated that the foamability of the LEW was increased by ultrasound-irradiation combined pretreatment to the highest value of 92.6% (irradiation dose = 33 kGy, ultrasound time = 6min, and ultrasound power = 300 W). Three significant proteins in LEW (ovalbumin, ovotransferrin, and lysozyme) were chosen to explore the change law on their physical and structural properties. Results indicated that ultrasound-irradiation combined pretreatment increased the solubility and reduced the pH and particle size of ovalbumin and lysozyme, thus enhancing the foamability of LEW. Furthermore, the fluorescence spectra changes implied the un-folding and destruction of ovalbumin, ovotransferrin, and lysozyme during the ultrasound-irradiation combined pretreatment. Moreover, circular dichroism spectroscopy analysis revealed that the pretreatment decreased α-helix and β-sheet of the ovalbumin, ovotransferrin, and lysozyme, which bring out the improvement of LEW foamability. The present study indicated that ultrasound-irradiation combined pretreatment had the potential to be implemented to enhance the foamability of LEW.