Comparative Study on Foaming Properties of Egg White with Yolk Fractions and Their Hydrolysates

From Hen Nutrition to Baking: Effects of Pomegranate Seed and Linseed Oils on Egg White Foam Stability and Sponge Cake Quality

This study aimed to verify that enriching hens' diets with pomegranate seed (PSO) and linseed oils (LSO) would maintain egg foaming and leavening capacity and improve the nutritional profile of egg-based products without compromising technological properties. It was shown in the previous studies that fortifying hen feed with PSO increased CLnA and CLA concentrations in raw eggs. In this study, two experiments with 25-week-old Hy-Line Brown laying hens have been carried out. Experiment 1 modified hens' feed by incorporating PSO (0.5-1.5%) and 1.5% LSO. In Experiment 2, hens received feed containing PSO (0.5-1.5%). This research involved cake preparation, quality evaluation, and the assessment of egg white foam properties (stability, density, and gas bubble distribution). The chemical composition of sponge cake was determined. Results showed that PSO and LSO in hen feed enhanced egg leavening properties, while egg white-based foam properties matched the control group. The cakes showed improved health-promoting properties due to CLA and CLnA presence. The research confirmed that these beneficial acids were retained in the final sponge cake.

Effect of Extraction Methods and Preheat Treatments on the Functional Properties of Pumpkin Seed Protein Concentrate

This study explores the effect of different extraction methods and preheat treatments in obtaining protein concentrate from pumpkin seed flour. The effects on the yield and functional properties of pumpkin seed protein concentrate (PSPC) were compared alongside microwave and conventional preheating methods using alkali, salt, and enzyme-assisted alkali extraction techniques. Analytical assessments included proximate analysis, soluble protein content, water solubility index (WSI), emulsification activity (EA) and stability (ES), foaming capacity (FC) and stability (FS), and antioxidant activity (AA). Hydration and structural analyses were performed via time-domain nuclear magnetic resonance (TD-NMR) Relaxometry and Fourier-Transform Infrared (FTIR) Spectroscopy. In addition, color measurements were performed to evaluate the visual quality of the samples. The alkali extraction method paired with microwave heating (MH-AE) significantly outperformed other techniques, with an extraction yield and protein content of approximately 55% and 77%, respectively. This study demonstrated the superior yield and functional properties of PSPC using MH-AE, opening opportunities for future research in optimizing plant-based protein extraction techniques.

Modification Effects of Microorganisms and Enzymes on Egg Components: A Review

In eggs, there are several components: eggshell (ES), eggshell membrane (ESM), egg white (EW), and egg yolk (EY). Many modification methods exist, such as thermal treatment, high pressure, freeze-thaw cycles, ultrasonic treatment, ozonation, phosphorylation, and acylation, all aimed at improving the functional properties of EW and EY. Additionally, microorganism and enzyme modifications have proven effective in enhancing the functional properties of EW and EY. ES and ESM are unique components of eggs. The eggshell is rich in calcium carbonate, while the eggshell membrane is rich in protein. The effective utilization of ES and ESM can help promote economic income in the poultry industry and benefit the environment. Research on the modification of ES and ESM has shown that microorganisms and enzymes have the potential to improve their functional properties. After modification, egg components can be utilized in the production of egg-based and other food products for improved performance. Furthermore, enzyme modification of egg components can produce bioactive peptides, which have the potential to treat specific diseases and may even be used in the biomedical field. This review primarily focuses on the effects of microorganisms and enzymes on the modification of egg components and summarizes the roles of microbial and enzymatic modifications in this context.

Preparation of microgel particles from egg yolk components by combining phospholipase A2 with high-pressure homogenization: Physicochemical, structural properties and their effects on foaming, processing stability of egg white protein

In this study, two types of microgel particles from egg yolk components were prepared by combining enzymatic hydrolysis with high-pressure homogenization (HPH), and their differences in physicochemical properties, foaming properties, and microstructure were compared. Results showed that the particle size of both types of microgel particles had decreased from 2744.07 ± 408.26 nm (egg yolk, EY) to 144.97 ± 3.19 nm (PLA2 hydrolyzed egg yolk microgel particles, PYM) and 535.07 ± 46.07 nm (egg yolk microgel particles hydrolyzed by PLA2, YMP), from 736.24 ± 34.61 nm (EG) to 182.76 ± 4.12 nm (PLA2 hydrolyzed egg yolk granules microgel particles, PGM) and 443.98 ± 27.09 nm (egg yolk granules microgel particles hydrolyzed by PLA2, GMP). Besides, their interfacial adsorption abilities were significantly improved, reflected in the increase values in overrun, from161.90 % ± 9.84 % (EY) to 269.64 % ± 16.73 % (PMY) and 307.20 % ± 16.09 % (YMP), from 189.21 % ± 5.02 % (EG) to 280.38 % ± 36.05 % (PGM) and 261.91 % ± 34.03 % (GMP). Their structural properties showed higher stabilities after treatments. When the microgel particles are applied to cakes, the specific volume was increased from 2.05 ± 0.1 mL/g (EY) to 2.25 ± 0.13 mL/g (PYM) and 2.45 ± 0.03 mL/g (YPM), and from 2.00 ± 0.09 mL/g (EG) to 2.51 ± 0.13 mL/g (PGM) and 2.75 ± 0.21 mL/g (GMP), respectively. The hardness and chewiness were reduced with both types of microgel particles from egg yolk components, which indicated their potential value as edible foam stabilizers in the baking industry.

Epigallocatechin gallate modification of physicochemical, structural and functional properties of egg yolk granules

The aim of this study was to prepare protein-polyphenol covalent complexes by treating egg yolk granules (EYG) with alkali in the presence of epigallocatechin gallate (EGCG) and characterize the physicochemical, structural, and functional properties of these covalent complexes. Results revealed that the optimal covalent binding occurred when the concentration of EGCG reached 0.15% (w/w), resulting in a grafting rate of 1.51 ± 0.03%. As the amount of EGCG increased, corresponding increases were observed in the particle size and ζ-potential of the complexes, thereby enhancing their stability. Furthermore, our analysis using fluorescence spectroscopy, FTIR, SEM, and SDS-PAGE collectively demonstrated the formation of a covalent complex between EYG and EGCG. Notably, the covalent complexes exhibited improved antioxidant activity and emulsifying properties. Overall, this study establishes a theoretical framework for the future practical application of EYG, emphasizing the potential of EGCG to modify its structural and functional characteristics.

Solvent Tolerance Improvement of Lipases Enhanced Their Applications: State of the Art

Lipases, crucial catalysts in biochemical synthesis, find extensive applications across industries such as food, medicine, and cosmetics. The efficiency of lipase-catalyzed reactions is significantly influenced by the choice of solvents. Polar organic solvents often result in a decrease, or even loss, of lipase activity. Conversely, nonpolar organic solvents induce excessive rigidity in lipases, thereby affecting their activity. While the advent of new solvents like ionic liquids and deep eutectic solvents has somewhat improved the activity and stability of lipases, it fails to address the fundamental issue of lipases' poor solvent tolerance. Hence, the rational design of lipases for enhanced solvent tolerance can significantly boost their industrial performance. This review provides a comprehensive summary of the structural characteristics and properties of lipases in various solvent systems and emphasizes various strategies of protein engineering for non-aqueous media to improve lipases' solvent tolerance. This study provides a theoretical foundation for further enhancing the solvent tolerance and industrial properties of lipases.

Effect of Lipase and Phospholipase A1 on Foaming and Batter Properties of Yolk Contaminated Egg White

Egg white (EW) is frequently used in bakery products because of its excellent foaming capabilities. However, egg yolk (EY) contamination often degrades the foaming characteristics of EW. The purpose of this study was to investigate the effect of different concentrations of phospholipase A1 (PLPA1) and lipase (LP) on EW. The changes in particle size distribution and potential before and after enzymatic digestion of EW with contaminated 0.5 wt% and 1.0%wt EY were tested. The foaming rate and foam stability were measured after the dispersions were digested with different concentrations of PLPA1 and LP. Additionally, the dispersion samples were used to prepare batter and angel cake, and the modulus, density, and microstructure of the batter were analyzed. Results showed that the potential absolute value increased when the EY was hydrolyzed by PLPA1. The distribution of yolk particle size showed a new aggregation and the average particle size decreased after LP hydrolysis. The dispersion samples hydrolyzed by PLPA1 and LP recovered all the properties of the samples at enzymatic concentrations of 500 U/g and 2500 U/g. This may be attributed to the changes in yolk particles resulting from the enzymatic digestion of EY and the production of amphiphilic lysophospholipids, fatty acids, and glycerol.