Investigation of the Structure and Allergic Potential of Whey Protein by Both Heating Sterilization and Simulation with Molecular Dynamics

Interactions between β-lactoglobulin and polyphenols: Mechanisms, properties, characterization, and applications

β-lactoglobulins (βLGs) have a wide range of applications in food because of their ability to emulsify, foam, and gel. This makes them good functional additives. However, their performance depends on temperature, pH, and mineral levels, so their functional qualities are limited in particular applications. How polyphenols (PPs) interact with βLG is crucial for the functional characteristics and quality of dietary compounds. In most food systems, a spontaneous interaction between proteins and PPs results in a "protein-PP conjugate," which is known to affect the sensory, functional, and nutraceutical qualities of food products. The βLG-PP conjugates can be used to enhance the quality of food. This article emphasizes analytical techniques for describing the characteristics of βLG-PP complexes/conjugates. It also goes over the functions of βLG-PP conjugates, including their solubility, thermal stability, emulsifying, and antioxidant qualities. The majority of βLG-PPs interactions is due to non-covalent (H-bonding, electrostatic interactions) or covalent bonds that are mostly caused by βLG or PP oxidation through enzymatic or non-enzymatic mechanisms. Furthermore, the conformation or type of proteins and PPs, as well as environmental factors like pH and temperature, have a significant impact on proteins-PPs interactions. Higher thermal stability, antioxidant activities, and superior emulsifying capabilities of the βLG-PP conjugates make them useful as innovative additives to enhance the quality and functions of food products.

Analysis of epitopes and structural responses in egg allergen Gal d 1 using bioinformatic tools and molecular dynamics simulation

Egg allergy is a growing concern worldwide. Investigating the allergenic and molecular characteristics of egg allergen Ovomucoid (Gal d 1) can enhance our understanding of egg allergies. In this study, the B-cell linear epitopes of Gal d 1 were predicted by using different bioinformatic tools, based on the primary sequence properties of Gal d 1, and obtained 10 potential B-cell linear epitopes. Meanwhile, we conducted molecular dynamics (MD) simulations to apply thermal and an oscillating electric field treatments to Gal d 1 in order to comprehend the structural alterations of Gal d 1 intuitively. The results indicated that Gal d 1 was a thermally stable protein, while the secondary structure and surface characteristics of Gal d 1 were obviously influenced by the combination of thermal stress and electric field, which finally resulted in conformational changes. This study provided a new way to understand the development of hypoallergenic egg products.

Allergenicity of Alternative Proteins: Reduction Mechanisms and Processing Strategies

The increasing popularity of alternative proteins has raised concerns about allergenic potential, especially for plant-, insect-, fungal-, and algae-based proteins. Allergies arise when the immune system misidentifies proteins as harmful, triggering IgE-mediated reactions that range from mild to severe. Main factors influencing allergenicity include protein structure, cross-reactivity, processing methods, and gut microbiota. Disruptions in gut health or microbiota balance heighten risks. Common allergens in legumes, cereals, nuts, oilseeds, single-cell proteins, and insect-based proteins are particularly challenging, as they often remain stable and resistant to heat and digestion despite various processing techniques. Processing methods, such as roasting, enzymatic hydrolysis, and fermentation, show promise in reducing allergenicity by altering protein structures and breaking down epitopes that trigger immune responses. Future research should focus on optimizing these methods to ensure that they effectively reduce allergenic risks while maintaining the nutritional quality and safety of alternative protein products.

Effects of γ-polyglutamic acid on the rheological, microstructural and sensory properties of low-fat yogurt

BACKGROUND

While low-fat yogurt offers numerous health benefits, its texture and sensory qualities are poor. This study aimed to investigate the effects of γ-polyglutamic acid (γ-PGA) on the rheological, microstructural and sensory properties of low-fat yogurt using rheological tests, scanning electron microscopy (SEM) and sensory evaluation.

RESULTS

The results showed that the syneresis of low-fat yogurt added with 0.15% γ-PGA was significantly (P < 0.05) reduced to 23.03%, compared to that of low-fat yogurt without γ-PGA (42.87%). An improvement in storage and loss moduli (G', G") and apparent viscosity was also observed. The power law model fitted to rheological data indicated that γ-PGA enhanced the viscoelasticity and strength of the gel network though interaction with casein gel, which might lead to changes in the moduli of yogurts. Microstructural observation via SEM confirmed the enhanced crosslinking between casein micelles and the filling effect of γ-PGA. Sensory liking scores were strongly correlated with rheological properties and apparent viscosity. The results of principal component analysis (PCA) confirmed the positive effects of γ-PGA on quality and rheological attributes of low-fat yogurt.

CONCLUSION

The results of this study provided valuable references for the potential use of γ-PGA as a fat replacer to stabilize the sensory quality of low-fat yogurt. © 2024 Society of Chemical Industry.

Structural and Stability Analysis of GRP Family Allergens Pru p 7 and Cry j 7, Which Cause Pollen and Food Allergy Syndrome

Cry j 7 is a 7 kDa cysteine-rich gibberellin regulatory protein (GRP) with six disulfide bonds. It was isolated from Japanese cedar as the pollen allergen in this study. It exhibits cross-reactivity with food allergens such as Pru p 7 from peach and causes pollen-food allergy syndrome (PFAS). In this work, recombinant Cry j 7 and Pru p 7 were successfully overexpressed using Pichia pastoris in a high-cell-density fermentation culture, and pure proteins were purified by reverse-phase HPLC. The characterization of Cry j 7 and Pru p 7 were performed by MS, CD, and 1H-NMR experiments to confirm the correct native conformation of Cry j 7 as well as Pru p 7. When compared, the results showed that Cry j 7 exhibits excellent stability in disulfide linkages and preserves its original structure up to 90 °C in various pH buffers in comparison to Pru p 7. Notably, NMR analyses indicated the greater mobility in the α-helix and loop regions of S38-C47 in Pru p 7 compared to those of Cry j 7. Furthermore, our results showed that the sensitivity of Cry j 7 to enzyme digestion differed from that of Pru p 7: Cry j 7 was more susceptible to proteolysis, while Pru p 7 displayed better resistance in the gastrointestinal tract. These variations in structural stability and sensitivity to proteolysis provide valuable insights into the allergenicity within the GRP family.

Effects of physical processing on food protein allergenicity: A focus on differences between animal and alternative proteins

In recent years, physical technologies have been widely employed to reduce food protein allergenicity due to their simplicity and stability. This paper summarizes recent research advances in these technologies, focusing on differences in their effects on allergenicity between animal and alternative proteins. The mechanisms of allergenicity reduction and the advantages and disadvantages of these technologies were compared. It was found that heating, although affording better allergenicity reduction than non-thermal treatment technologies, affects other properties of the food. Because of their higher molecular weights and more complex structures, animal proteins are less affected by physical technologies than alternative proteins. It is worth noting that there is a scarcity of existing technology to reduce the allergenicity of food proteins, and more technologies should be explored for this purpose. In addition, better allergenicity-reducing processing technologies should be designed from the perspectives of processing conditions, technological innovations, and combined processing technologies in the future.

Effect of Thermal Processing on Food Allergenicity: Mechanisms, Application, Influence Factor, and Future Perspective

Thermally processed foods are essential in the human diet, and their induced allergic reactions are also very common, seriously affecting human health. This review covers the effects of thermal processing on food allergenicity, involving boiling, water/oil bath heating, roasting, autoclaving, steaming, frying, microwave heating, ohmic heating, infrared heating, and radio frequency heating. It was found that thermal processing decreased the protein electrophoretic band intensity (except for infrared heating and radio frequency heating) responsible for destruction of linear epitopes and changed the protein structure responsible for the masking of linear/conformational epitopes or the destruction of conformational epitopes, thus decreasing food allergenicity. The outcome was related to thermal processing (e.g., temperature, time) and food (e.g., types, pH) condition. Of note, as for conventional thermal processing, it is necessary to control the generation of the advanced glycation end products in roasting/baking and frying, and the increase of structural flexibility in boiling and water/oil bath heating, autoclaving, and steaming must be controlled; otherwise, it might increase food allergenicity. As for novel thermal processing, the temperature nonuniformity of microwave and radio frequency heating, low penetration of infrared heating, and unwanted metal ion production of ohmic heating must be considered; otherwise, it might be the nonuniformity and low effect of allergenicity reduction and safety problems.

Modulating Whey Proteins Antigenicity with Lactobacillus delbrueckii subsp. bulgaricus DLPU F-36 Metabolites: Insights from Spectroscopic and Molecular Docking Studies

Numerous studies have highlighted the potential of Lactic acid bacteria (LAB) fermentation of whey proteins for alleviating allergies. Nonetheless, the impact of LAB-derived metabolites on whey proteins antigenicity during fermentation remains uncertain. Our objective was to elucidate the impact of small molecular metabolites on the antigenicity of α-lactalbumin (α-LA) and β-lactoglobulin (β-LG). Through metabolomic analysis, we picked 13 bioactive small molecule metabolites from Lactobacillus delbrueckii subsp. bulgaricus DLPU F-36 for coincubation with α-LA and β-LG, respectively. The outcomes revealed that valine, arginine, benzoic acid, 2-keto butyric acid, and glutaric acid significantly diminished the sensitization potential of α-LA and β-LG, respectively. Moreover, chromatographic analyses unveiled the varying influence of small molecular metabolites on the structure of α-LA and β-LG, respectively. Notably, molecular docking underscored that the primary active sites of α-LA and β-LG involved in protein binding to IgE antibodies aligned with the interaction sites of small molecular metabolites. In essence, LAB-produced metabolites wield a substantial influence on the antigenic properties of whey proteins.

Covalent conjugation with quercetin mitigates allergenicity of the bee pollen allergen Bra c p in a murine model

Profilin family members are highly conserved food allergens that can cause widespread cross-allergic reactions. Our previous research has demonstrated that the covalent conjunction with quercetin can disrupt the conformational epitopes of a profilin allergen, Bra c p. In this study, we further investigated the intrinsic molecular mechanisms using molecular dynamics simulations. Moreover, the allergenic potential of Bra c p and its conjugate with quercetin was assessed in BALB/c mice. The results showed that continuous interaction with quercetin increased the molecular motion of Bra c p, causing changes to its α-helices and exposing hydrophobic residues which altered antigenic epitopes. Additionally, mice treated with Bra c p-quercetin conjugate showed reduced allergic reactions compared to those treated with Bra c p alone by regulating purine metabolism, calcium signaling, and CD4+CD25+ Tregs proportion. Quercetin conjugation decreases the allergenicity of Bra c p, providing a scientific foundation for reducing the profilin allergens in food.

Textural Restoration of Broiler Breast Fillets with Spaghetti Meat Myopathy, Using Two Alginate Gels Systems

The effects of salt-sensitive alginate ("A") and a two-component salt-tolerant alginate system ("B") used at a 0.5% or 1.0% level were evaluated in normal breast (NB) chicken fillets and in spaghetti meat (SM) fillets. Minced raw and cooked SM samples showed higher cooking loss (p < 0.05) and lower penetration force compared to NB meat. Both alginate systems significantly raised the penetration force in raw samples and decreased cooking loss (p < 0.05). Adding 1% of "A" or 0.5% "B" to SM, without salt, resulted in a similar penetration force as the cooked NB meat, while 1% "B" with salt resulted in a higher penetration force. Excluding salt from SM samples while adding alginate "A" or "B" improved texture profiles, but not to the same level as using NB without additives. Overall, salt, together with alginate "B", improved the texture of SM to that of normal meat without myopathy.

Recent Advances in Polymer-Based Biosensors for Food Safety Detection

The excessive use of pesticides and drugs, coupled with environmental pollution, has resulted in the persistence of contaminants on food. These pollutants tend to accumulate in humans through the food chain, posing a significant threat to human health. Therefore, it is crucial to develop rapid, low-cost, portable, and on-site biosensors for detecting food contaminants. Among various biosensors, polymer-based biosensors have emerged as promising probes for detection of food contaminants in recent years, due to their various functions such as target binding, enrichment, and simple signal reading. This paper aims to discuss the characteristics of five types of food pollutants-heavy metals, pesticide residues, pathogenic bacteria, allergens, and antibiotics-and their adverse effects on human health. Additionally, this paper focuses on the principle of polymer-based biosensors and their latest applications in detecting these five types of food contaminants in actual food samples. Furthermore, this review briefly examines the future prospects and challenges of biosensors for food safety detection. The insights provided in this review will facilitate the development of biosensors for food safety detection.