Changes in structural and functional properties of whey protein cross-linked by polyphenol oxidase

Lipid matrix-specific pretreatment method for enhancing the extractability and allergenicity maintenance of bovine milk allergens in ELISA detection

The presence of various components in the food matrix makes allergen detection difficult and inaccurate, and pretreatment is an innovative breakthrough point. Food matrices were categorised based on their composition. Subsequently, a pretreatment method was established using a combination of ultrasound-assisted n-hexane degreasing and weakly alkaline extraction systems to enhance the detection accuracy of bovine milk allergens. Results showed that more allergens were obtained with less structural destruction, as demonstrated using immunological quantification and spectral analysis. Concurrently, allergenicity preservation was confirmed through liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, a KU812 cell degranulation model, and western blotting. The method exhibited good accuracy (bias, 8.47%), repeatability (RSDr, 1.52%), and stability (RSDR, 5.65%). In foods with high lipid content, such as chocolate, the allergen content was 2.29-fold higher than that of commercial kits. Laser confocal scanning microscopy (LCSM) and scanning electron microscopy (SEM) analyses revealed a significant decrease in fat content after post-pretreatment using our method. In addition, colloidal stability surpassed that achieved using commercial kits, as indicated through the PSA and zeta potential results. The results demonstrated the superiority of the extractability and allergenicity maintenance of lipid matrix-specific pretreatment methods for improving the accuracy of ELISA based allergen detection in real food.

Ca2+-promoted free radical grafting of whey protein to EGCG: As a novel nanocarrier for the encapsulation of apigenin

Whey protein (WP) is often used as a delivery carrier due to its superior biological activity and nutritional value. Covalent binding of WP to epigallocatechin gallate (EGCG) can significantly improve the performance of WP in encapsulated materials. Nevertheless, the preparation of WP-EGCG covalent complexes still suffers from low grafting rates. Studies have shown that calcium ions (Ca2+) can modify the structure of proteins. We therefore explored the effect of calcium chloride (CaCl2) on the free radical grafting of EGCG and WP. The experimental results showed that the grafting rate of free radicals increased by 17.89% after adding Ca2+. Furthermore, the impact of WP-EGCG-Ca2+ covalent complex on the entrapment efficiency of apigenin (AP) was further examined, and the results revealed that the entrapment rate could reach 93.66% at an apigenin concentration of 0.2 mg/mL. Simulated gastrointestinal digestion showed that WP-EGCG-Ca2+ covalent complex could significantly improve the bioavailability of AP. The study provides new ideas to broaden the application of WP as a carrier for delivering bioactive substances.

Experimental investigation into the implications of low-intensity magnetic field treatment on the structural and functional properties of rapeseed meal during biofermentation

The functionality of rapeseed meal is limited, to acquire more utilization, the functional attributes were improved by altering its structural features using magnetic field-assisted solid fermentation. The magnetic treatment was performed every 24 h (specifically at 24, and 48 h), each treatment having a duration of 4 h. The magnetic intensity was set at 120 Gs, and the fermentation temperature 37 °C. Magnetic field-assisted solid fermentation resulted in higher surface hydrophobicity, fluorescence intensity, UV absorption, and sulfhydryl groups of rapeseed meal. Magnetic field treatment considerably enhanced solubility, antioxidant activity, emulsifying activity, and stability by 8.8, 19.5, 20.7, and 12.3 %, respectively. Magnetic field-assisted solid fermentation also altered rapeseed meal structure, as shown by scanning electron microscopy, atomic force microscopy, and Raman spectroscopy outcomes. Correlation analysis displayed positive interrelationships between functional characteristics, and surface hydrophobicity, β-sheets, and polydispersity index.

Effect of ultrasound-assisted Maillard reaction on glycosylation of goat whey protein: Structure and functional properties

Goat whey protein (GWP) has a rich amino acid profile and good techno-functional attributes but still has limited functional performance for certain applications. This study introduces an innovative ultrasound-assisted Maillard reaction to enhance GWP's functional properties by conjugating it with either gum Arabic (GA) or citrus pectin (CP). Sonication accelerated the Maillard reaction, and the glycosylation of GWP was significantly enhanced after optimization of the conjugation conditions. Gel electrophoresis examination verified the creation of GWP-polysaccharide conjugates, while scanning electron microscopy analysis revealed structural modifications caused by polysaccharide grafting and sonication. The use of ultrasound in the Maillard reaction notably enhanced the solubility, foaming capacity, and emulsifying attributes of the GWPs. Among the conjugates, the GWP-GA ones exhibited the best functional properties. Our findings suggest that this approach can notably improve the functional attributes of GWPs, thus broadening their potential uses in the food sector and beyond.

Dietary Polyphenols, Plant Metabolites, and Allergic Disorders: A Comprehensive Review

Given the ongoing rise in the occurrence of allergic disorders, alterations in dietary patterns have been proposed as a possible factor contributing to the emergence and progression of these conditions. Currently, there is a significant focus on the development of dietary therapies that utilize natural compounds possessing anti-allergy properties. Dietary polyphenols and plant metabolites have been intensively researched due to their well-documented anti-inflammatory, antioxidant, and immunomodulatory characteristics, making them one of the most prominent natural bioactive chemicals. This study seeks to discuss the in-depth mechanisms by which these molecules may exert anti-allergic effects, namely through their capacity to diminish the allergenicity of proteins, modulate immune responses, and modify the composition of the gut microbiota. However, further investigation is required to fully understand these effects. This paper examines the existing evidence from experimental and clinical studies that supports the idea that different polyphenols, such as catechins, resveratrol, curcumin, quercetin, and others, can reduce allergic inflammation, relieve symptoms of food allergy, asthma, atopic dermatitis, and allergic rhinitis, and prevent the progression of the allergic immune response. In summary, dietary polyphenols and plant metabolites possess significant anti-allergic properties and can be utilized for developing both preventative and therapeutic strategies for targeting allergic conditions. The paper also discusses the constraints in investigating and broad usage of polyphenols, as well as potential avenues for future research.

Structural, functional and antioxidant properties of Lentinus edodes protein hydrolysates prepared by five enzymes

The purpose of this study was to investigate structural, functional and antioxidant properties of Lentinus edodes protein hydrolysates (LEPHs) by alcalase, protamex, trypsin, papain and neutrase. Structural and functional properties were determined using gel electrophoresis, Fourier transform infrared spectroscopy, laser scattering, fluorescence spectroscopy, emulsifying properties etc. Antioxidant activities were detected by Fe2+ chelating, hydroxyl and DPPH radical scavenging assays. Enzymatic hydrolysis destroyed secondary and tertiary structures of Lentinus edodes protein, decreased its molecular weight and particle size, particularly hydrolysate prepared by alcalase with the highest hydrolytic degree (32.86 ± 0.98 %), the smallest particle (130.77 ± 1.85 nm) and molecular weight (5.86 kDa). Moreover, alcalase hydrolysate exhibited the highest emulsifying stability, the strongest hydroxyl radical scavenging activity and Fe2+ chelating ability among LEPHs. Whilst trypsin hydrolysate displayed the highest DPPH radical scavenging, foaming and fat absorption capacity. These results provided basis for LEPH as ingredients to be used for food industry.

Inhibition effect of epicatechin gallate on acid phosphatases from rainbow trout (Oncorhynchus mykiss) liver by multispectral and molecular docking

Inhibition of acid phosphatase, which significantly contributes to inosine 5'-monophosphate (IMP) degradation, is crucial for preventing flavor deterioration of aquatic products during storage. In this study, the inhibitory effect of epicatechin gallate (ECG) on the activity of acid phosphatase isozymes (ACPI and ACPII) was analyzed using inhibition kinetics, fluorescence spectroscopy, isothermal titration calorimetry, and molecular simulation. ACPI and ACPII with molecular weights of 59.5 and 37.3 kDa, respectively, were purified from rainbow trout liver. ECG reversibly inhibited ACPI and ACPII activities via mixed-type inhibition, with half maximal inhibitory concentration (IC50) of 0.24 ± 0.01 mmol/L and 0.27 ± 0.03 mmol/L, respectively. Fluorescence spectra indicated that ECG statically quenched the intrinsic fluorescence of ACPI and ACPII. ECG could spontaneously bind to ACPI and ACPII through hydrogen bonding and van der Waals forces and exhibited a higher affinity for ACPI than for ACPII. In addition, molecular dynamic simulation revealed that ECG-ACPI and ECG-ACPII complexes were relatively stable during the entire simulation process. Our findings provide a theoretical basis for the use of ECG as an inhibitor of ACP to improve the flavor of aquatic products.

Whey protein isolate-resveratrol complex as a radical scavenging foaming ingredient with increased ultraviolet stability

Functional foaming food ingredients play a vital role in preparing healthcare foods, however, the weak foamability and low photostability of ingredients severely limit their further development. Herein, whey protein isolate-resveratrol complexes (WPI-RES) were fabricated to address these challenges. Multi-spectral analysis and molecular simulation results revealed the key driving forces of hydrogen bonding and hydrophobic interactions to promote the formation of WPI-RES complexes, leading to the enhanced foamability and emulsifying properties of WPI after binding with RES. Importantly, the robust radical scavenging activity of RES within WPI was maintained under UV light irradiation compared to that of free RES as identified by DPPH assay, which was presumably due to inhibited photoisomerization of RES after binding to WPI. This work provides a promising foaming ingredient with increased ultraviolet stability and radical scavenging activity, paves the way to develop stable health-promoting foaming food products.

The biological activity, functionality, and emulsion stability of soybean meal hydrolysate-proanthocyanidin conjugates

The use of by-product hydrolysates as functional ingredients in food production is becoming more widespread. We hypothesized that the covalent binding of proanthocyanidin (PC) to soybean meal hydrolysates (SMHs) will improve the biological activity and function of the SMHs. Accordingly, we investigated the structure, antioxidant activity, and emulsion stability of SMHs after covalent conjugation with different concentrations of PC. An increase in PC addition resulted in the development of more high-molecular-weight SMHs-PC conjugates (40 kDa). The observed increase in the random coil content indicated that greater unfolding and disordered structure formation occurred with increasing PC addition. In addition, the fluorescence intensity and surface hydrophobicity of the SMHs increased, suggesting the presence of free amino acids, which likely contributed to the antioxidant activity and emulsifying properties of the SMHs. Addition of 3.0 mg/mL PC gave the SMHs-PC conjugates the highest antioxidant activity (ABTS+ and DPPH radical scavenging capacities of 89.08 ± 0.47 and 40.90 ± 1.53%, respectively) and emulsifying activity index (79.13 ± 2.80 m2/g), which may be attributed to protein unfolding and maximization of the polyphenol content when PC was covalently bound to the SMHs. Moreover, the SMHs-PC emulsion with 2.0 mg/mL PC showed the smallest particle size and highest viscosity, presenting promising potential as an emulsifier with high biological activity in food.

Slow-digestive yeast protein concentrate: An investigation of its in vitro digestibility and digestion behavior

Yeast protein concentrate, a by-product of the fermentation industry waste, is a potential alternative protein source with high nutritional quality, environmental sustainability, and functional properties. However, its digestibility and digestion behavior are poorly understood. In this study, we compared the in vitro digestion behavior of yeast protein concentrate and whey protein concentrate using simulated gastrointestinal conditions. We found that yeast protein concentrate had lower digestibility than whey protein concentrate (31.25% vs. 86.23% at 120 min of pepsin digestion and 75.12% vs. 95.2% at 120 min of pancreatin digestion). Yeast protein concentrate differed from whey protein concentrate in microstructure, secondary structure, and amino acid composition, which may affect its digestion behavior. Compared to whey protein concentrate, a higher level of β-sheets and a lower zeta potential explain the slow-digesting property of yeast protein concentrate. Yeast protein concentrate also underwent depolymerization and Plastein reaction during digestion. These results provided valuable information for developing and applying yeast protein concentrate as an alternative to conventional animal protein.

Dietary Polyphenols-Natural Bioactive Compounds with Potential for Preventing and Treating Some Allergic Conditions

In light of the constantly increasing prevalence of allergic diseases, changes in dietary patterns have been suggested as a plausible environmental explanation for the development and progression of these diseases. Nowadays, much attention has been paid to the development of dietary interventions using natural substances with anti-allergy activities. In this respect, dietary polyphenols have been studied extensively as one of the most prominent natural bioactive compounds with well-documented anti-inflammatory, antioxidant, and immunomodulatory properties. This review aims to discuss the mechanisms underlying the potential anti-allergic actions of polyphenols related to their ability to reduce protein allergenicity, regulate immune response, and gut microbiome modification; however, these issues need to be elucidated in detail. This paper reviews the current evidence from experimental and clinical studies confirming that various polyphenols such as quercetin, curcumin, resveratrol, catechins, and many others could attenuate allergic inflammation, alleviate the symptoms of food allergy, asthma, and allergic rhinitis, and prevent the development of allergic immune response. Conclusively, dietary polyphenols are endowed with great anti-allergic potential and therefore could be used either for preventive approaches or therapeutic interventions in relation to allergic diseases. Limitations in studying and widespread use of polyphenols as well as future research directions are also discussed.

Development of a Two-Step Hydrolysis Hypoallergenic Cow's Milk Formula and Evaluation of Residue Allergenicity by Peptidomics and Immunoreactivity Analysis

Cow's milk allergy (CMA) is an abnormal immune response that severely affects the nutritional supplementation of allergic infants. Currently, only a limited number of hypoallergenic formulas are available on the market, and these are only categorized according to their degree of hydrolysis, which still poses an allergy risk and cannot be consumed by CMA patients, especially infants. To address this issue, we developed a two-step hydrolysis hypoallergenic formula targeting destruction of allergen epitope from whey protein. Then, a comprehensive evaluation system was constructed, including peptidomics analysis, in vivo and in vitro allergenicity assessments, revealing allergic changes in the product from the epitope structure level to the immunological level. The results showed that 97.14% of hydrolyzed peptides from α-lactalbumin and β-lactoglobulin did not contain allergenic epitopes after treatment with trypsin and flavourzyme. In vitro and in vivo allergenicity assessment results confirmed that the two-step hydrolysis method effectively reduced the allergenicity of whey protein. Compared with the common milk powder, the hypoallergenic formula induced lower levels of basophil degranulation and relieved the body's anaphylactic symptoms caused by cow milk. This study provides a promising solution to the limited hypoallergenic formula problem and may benefit allergic infants who require nutritional supplements.

The complexes of soybean protein isolate and procyanidin B2 have synergistic hypolipidemic activity at the cellular level by activating the AMPKα pathway

The alkali method was used to prepare soybean protein isolate (SPI) and procyanidin B2 (PCB2) complexes, and the interaction between SPI and PCB2 was studied using multi-spectroscopic methods. The human hepatoma (HepG2) cell hyperlipidemia model was used to explore whether SPI-PCB2 has the potential for synergistic hypolipidemia. According to the findings, PCB2 was primarily linked to SPI via C-S and C-N bonds, and the addition of PCB2 reduced the α-helix structure content of SPI by 4.1%. At the cellular level, the optimal SPI-PCB2 ratio for lowering blood lipids was 1:1. Compared with the model group, the TG content and TC content in the 1:1 group were reduced by 28.7% and 26.3%, respectively. Western blot analysis revealed that SPI-PCB2 = 1:1 exerted synergistic hypolipidemic activity mainly by activating adenosine monophosphate-activated protein kinase α (AMPKα) phosphorylation, inhibiting 3-hydroxy-3-methylglutaryl CoA reductase (HMGCR) and fatty acid synthetase (FAS) protein expression, and upregulating carnitine palmitoyl transferase 1A (CPT1A) protein activity.