Precooked state based on protein denaturation kinetics impacts moisture status, protein oxidation and texture of prepared chicken breast.

The quality of meat in prepared dishes deteriorates due to excessive protein denaturation resulting from precooking, freezing, and recooking. This study aimed to link the precooked state with chicken breast's recooked quality. Cooked Value (CV), based on protein denaturation kinetics, was established to indicate the doneness of meat during pre-heating. The effects of CVs after pre-heating on recooked qualities were investigated compared to fully pre-heated samples (control). Mild pre-heating reduced water migration and loss. While full pre-heating inhibited protein oxidation during freezing, intense oxidation during pre-heating led to higher oxidation levels. Surface hydrophobicity analysis revealed that mild pre-heating suppressed aggregation during recooking. These factors contributed to a better texture and microstructure of prepared meat with mild pre-heating. Finally, a potential mechanism of how pre-heating affects final qualities was depicted. This study underlines the need for finely controlling the industrial precooking process to regulate the quality of prepared meat.

Unraveling the impact of thermal modulation in heating and cooling dies on the fibrous structure of high-moisture meat alternatives.

We aimed to create high-moisture plant-based meat alternatives (HPMAs) that closely mimic the fibrous structure found in conventional meat. To achieve this goal, we focused on the impact of modulating the heating and cooling die temperatures during the extrusion process on the structural properties of HPMAs. The optimal temperatures for the heating and cooling dies were determined to be 160 and 50 °C, respectively, following a comprehensive analysis of various quality characteristics. These included assessments of cutting strength, texturization degree, moisture content, and microstructure. Analyzing the correlation coefficients between heating and cooling die temperatures and the quality characteristics of HPMAs revealed that modulating the cooling die temperature has a greater impact on quality characteristics than modulating the heating die temperature. The quality characteristics of HPMAs were also compared with those of boiled and sous-vide cooked chicken breasts. The optimal HPMA exhibited the most similar fibrous macro- and micro-structure to sous-vide cooked chicken breast. Consequently, our study highlights the importance of modulating the heating die and cooling die temperatures, among various process parameters of high-moisture extrusion cooking, which is crucial for producing HPMAs closely resembling conventional meat.

Algerian Prickly Pear Seed By-Products: Fatty Acids Composition, Antioxidant, Enzyme Inhibitory Activities towards Tyrosinase, Urease, α-Amylase, and Cholinesterase, along with the Ability to Protect from Thermal Protein Denaturation.

Prickly pear seed is a source of the most expensive oil in the world, which is rich in vitamins and polyunsaturated fatty acids. Its extraction generates a large quantity of press cake. These two by-products need to be valued. The current study aimed to assess the fatty acid composition of oil and the phytochemical composition of press cake. In addition, the antioxidant and the inhibition of thermal protein denaturation effects of both Algerian seed by-products were evaluated with their inhibitory action against the activities of urease, tyrosinase, α-amylase, and cholinesterase enzymes. The GC MS analysis result revealed the richness of our oil in linoleic (74%) and palmitic (13%) acids methyl esters, respectively. The chemical composition of press cake was characterized by a high value of dry matter (94.94 ± 0.05%), especially the carbohydrates (85.13 ± 0.94%). The results of antioxidant activity presented by IC50 and A0.5 ranged from 7.51 ± 0.03 to 88.10 ± 0.92 µg/mL. Furthermore, the IC50 values were 40.19 ± 1.21 and 61.18 ± 0.03 µg/mL in thermal protein denaturation assay, and ranging from 22.97 ± 0.72 to 385.99 ± 0.27 µg/mL for the inhibition of enzymatic activities. These results indicate that the studied oil can be one of the strongest oils for its impressive effects and also encourage us to reuse its press cake in feed livestock.

Unraveling the role of peanut protein in baijiu-peanut pairing flavor complexity: A focus on ethanol-induced denaturation.

Food processing, cooking, and consumption introduce various factors that affect food flavor, distinguishing it from its objective composition. This study focuses on liquor-accompanying food pairing, investigating the interaction between baijiu aroma compounds and peanut proteins, and the effect of ethanol on it. Peanut globulins significantly inhibited the release of baijiu aroma compounds through hydrogen bonding (2.63-3.23 Å), hydrophobic interactions, and covalent reactions (-2.85 to -5.64 kcal/mol), resulting in flavor modification. In the presence of ethanol, peanut globulins adopt a more compact and aggregated structure, reducing their affinity for binding aroma compounds. Surprisingly, this structural change promotes a salting-out effect, significantly promoting the release of aldehydes, phenols, and aromatic compounds, enhancing the grassy, floral, and sweet aroma of baijiu. This finding improves the understanding of alcohol pairing and proposes a novel strategy for enhancing the overall flavor profile of baijiu by modifying accompanying food choices.

Turmeric-Black Cumin Essential Oils and Their Capacity to Attenuate Free Radicals, Protein Denaturation, and Cancer Proliferation.

Turmeric rhizomes (Curcuma longa) and black cumin seeds (Nigella sativa) are polyherbal ingredients used for the management of cancer and other chronic inflammatory diseases in Nigerian ethnomedicine. Previous studies have shown the antioxidant, anti-inflammatory, and anticancer activities of the individual plant extracts. However, the two spices have not been biologically potentiated in their combined form. Therefore, this study obtained essential oils (EOs) from the combined spices and evaluated their inhibitory effects on free radicals, protein denaturation, and cancer proliferation. The EOs were extracted by hydro-distillation (HD) and characterized by gas chromatography-mass spectrometry (GC-MS). In vitro antioxidant assessment was conducted based on DPPH, hydrogen peroxide (H2O2), nitric oxide (NO), and ferric ion (Fe3+) radical scavenging assays. The cytotoxicity of the oil against non-tumorigenic (HEK293) and cancerous (HepG2 and HeLa) cell lines was determined following the MTT cell viability assay. An in silico molecular docking analysis of the oil constituents was also performed. Six batches of EOs I-VI were afforded, comprising twenty-two major constituents, with aromatic Ar-turmerone being the most prominent compound. There was a marked improvement in the bioactivity of the oils upon repeated HD and as a combination. The batch VI oil exhibited the best activity, with a cytotoxicity (CC50) of 10.16 ± 1.69 µg/100 µL against the HepG2 cell line, which was comparable to 5-fluorouracil (standard, CC50 = 8.59 ± 1.33 µg/100 µL). In silico molecular docking suggested δ-curcumene, Ar-curcumene, Ar-turmerol, and Ar-turmerone among the promising compounds based on their high binding energy scores with NOX2, NF-κB, and mdm2 proteins. In conclusion, the oils from the turmeric-black cumin combined possess a considerable inhibition ability against free radicals, protein denaturation, and cancer proliferation. This study's findings further underscore the effectiveness of turmeric-black cumin as a polyherbal medicinal ingredient.

Uncovering quality changes of shrimp (Penaeus vannamei) during solar drying and its relationship with protein-related properties.

This study explored the intrinsic relationship between the quality traits and protein-related property changes during the solar drying of shrimps (Penaeus vannamei). During drying, the shrimp exhibited a gradual decline in L*a*b* values and a notable increase in the hardness and chewiness. Proteins were degraded and oxidized. Especially, the trichloroacetic acid-soluble peptide and carbonyl contents increased, whereas the total sulfhydryl content decreased. The proportions of different types of intramolecular bonds were significantly changed. The ionic and hydrogen bonds greatly decreased to 10.72% and 9.05% and the hydrophobic and disulfide bonds notably increased to 19.38% and 28.19%, indicating the changes in the spatial structure of the protein and its denaturation during the drying process. The Pearson's correlation analysis showed that protein degradation and denaturation greatly affected the textural properties and protein oxidation caused color changes. The result of this work provides a theoretical support for improving the quality of shrimp products.

Effects of contact ultrasound coupled with infrared radiation on drying kinetics, water migration and physical properties of beef during hot air drying.

Drying, as a critical step in the production of air-dried beef, has a direct impact on the quality of the final product. Innovatively, a composite system incorporating contact ultrasound (CU) and infrared radiation (IR) as auxiliary measures within a hot air drying (HAD) framework was built in this research, and the effects of these techniques on the drying kinetics, protein denaturation, and moisture transformation of air-dried beef were investigated. In comparison to HAD treatment, the integrated CU and IR (CU-IRD) system displayed marked enhancements in heat and moisture transport efficiency, thereby saving 36.84% of time expenditure and contributing favorably to the improved moisture distribution of the end-product. This was mainly ascribed to the denaturation of myosin induced by IR thermal effect and the micro-channel produced by CU sponge effect, thus increasing T2 relaxation time and the proportion of free water. In conclusion, the composite system solved the problem of surface hardening and reduces hardness and chewiness of air-dried beef by 40.42% and 45.25% respectively, but inevitably increased the energy burden by 41.60%.

Assessment of the impact of whey protein hydrolysate on myofibrillar proteins in surimi during repeated freeze-thaw cycles: Quality enhancement and antifreeze potential.

The quality of surimi, widely used in processed seafood, is compromised by freeze-thaw cycles, leading to protein denaturation and oxidative degradation. The objective of this study is to explore the effects of adding natural whey peptide hydrolysate (WPH) on the myofibrillar proteins of repeatedly freeze-thawed surimi. Results indicated surimi treated with 15% WPH exhibited only a 128% increase in surface hydrophobicity and a maximum peroxide value of 7.84 µg/kg, significantly lower than the control group. Additionally, salt-soluble protein content, emulsification activity, and stability decreased with the increase in freeze-thaw cycles. With a 15% WPH offering the most significant protective effect, evidenced by reductions of only 25.02%, 42.52% and 37.02% in salt-soluble protein content, emulsification activity, and stability, respectively. These outcomes demonstrate that WPH effectively reduces protein denaturation during repeated freeze-thaw processes. Future research should explore the molecular mechanisms underlying WPH's protective effects and evaluate their applicability in other food systems.

NMR Dynamic View of the Destabilization of WW4 Domain by Chaotropic GdmCl and NaSCN.

GdmCl and NaSCN are two strong chaotropic salts commonly used in protein folding and stability studies, but their microscopic mechanisms remain enigmatic. Here, by CD and NMR, we investigated their effects on conformations, stability, binding and backbone dynamics on ps-ns and µs-ms time scales of a 39-residue but well-folded WW4 domain at salt concentrations ≤200 mM. Up to 200 mM, both denaturants did not alter the tertiary packing of WW4, but GdmCl exerted more severe destabilization than NaSCN. Intriguingly, GdmCl had only weak binding to amide protons, while NaSCN showed extensive binding to both hydrophobic side chains and amide protons. Neither denaturant significantly affected the overall ps-ns backbone dynamics, but they distinctively altered µs-ms backbone dynamics. This study unveils that GdmCl and NaSCN destabilize a protein before the global unfolding occurs with differential binding properties and µs-ms backbone dynamics, implying the absence of a simple correlation between thermodynamic stability and backbone dynamics of WW4 at both ps-ns and µs-ms time scales.

Ingredient Functionality of Soy, Chickpea, and Pea Protein before and after Dry Heat Pretreatment and Low Moisture Extrusion.

This study investigates the impact of dry heat pretreatment on the functionality of soy, chickpea, and pea protein ingredients for use in texturized vegetable protein (TVP) production via low moisture extrusion. The protein powders were heat-treated at temperatures ranging from 80 °C to 160 °C to modulate the extent of protein denaturation and assess their effects on RVA pasting behavior, water absorption capacity (WAC), and color attributes. The results indicate that the pretreatment temperature significantly influenced the proteins' functional properties, with an optimal temperature of 120 °C enhancing pasting properties and maintaining WAC, while a higher pretreatment temperature of 160 °C led to diminished ingredient functionality. Different protein sources exhibited distinct responses to heat pretreatment. The subsequent extrusion processing revealed significant changes in extrudate density and color, with increased density and darkness observed at higher pretreatment temperatures. This research provides insights into the interplay between protein sources, pretreatment conditions, and extrusion outcomes, highlighting the importance of controlled protein denaturation for developing high-quality, plant-based meat analogues. The findings have broad implications for the optimization of meat analogue manufacturing, with the aim of enhancing the sensory experience and sustainability of plant-based foods.

Deciphering the Thermal Stability of Bacteriophage MS2-Derived Virus-like Particle and Its Engineered Variant.

RNA bacteriophage MS2-derived virus-like particles (VLPs) have been widely used in biomedical research as model systems to study virus assembly, structure-function relationships, vaccine development, and drug delivery. Considering the diverse utility of these VLPs, a systemic engineering approach has been utilized to generate smaller particles with optimal serum stability and tissue penetrance. Additionally, it is crucial to demonstrate the overall stability of these mini MS2 VLPs, ensuring cargo protection until they reach their target cell/organ. However, no detailed analysis of the thermal stability and heat-induced disassembly of MS2 VLPs has yet been attempted. In this work, we investigated the thermal stability of both wild-type (WT) MS2 VLP and its "mini" variant containing S37P mutation (mini MS2 VLP). The mini MS2 VLP exhibits a higher capsid melting temperature (Tm) when compared to its WT MS2 VLP counterpart, possibly attributed to its smaller interdimer angle. Our study presents that the thermal unfolding of MS2 VLPs follows a sequential process involving particle destabilization, nucleic acid exposure/melting, and disassembly of VLP. This observation underscores the disruption of cooperative intersubunit interactions and protein-nucleic acid interactions, shedding light on the mechanism of heat-induced VLP disassembly.

Heat-moisture treatment can modulate all-purpose wheat flour for short dough biscuit making: Evidences and mechanism.

In view of the merits of all-purpose wheat flour (APWF) to soft wheat flour (SWF) in cost and protein supply, the feasibility of heat-moisture treatment (HMT, 19% moisture for 1 h at 60, 80 and 100 °C, respectively) to modify APWF as a substitute SWF in making short dough biscuits was explored. For underlying mechanisms, on the one hand, HMT reduced the hydration capacity of damaged starch particles by coating them with denatured proteins. On the other hand, HMT at 80 °C and 100 °C significantly denatured gluten proteins to form protein aggregates, highly weakening the gluten network in dough. These two aspects jointly conferred APWF dough with higher deformability and therefore significantly improved the qualities of biscuits. Moreover, the qualities of biscuits from APWF upon HMT-100 °C were largely comparable to that from SWF, even higher values were concluded in spread ratio, volume, specific volume and consumer acceptance.

The interaction of thiocyanate with peptides-A computational study.

According to the Hofmeister series, thiocyanate is the strongest "salting in" anion. In fact, it has a strong denaturant activity against the native state of globular proteins. A molecular level rationalization of the Hofmeister series is still missing, and therefore the denaturant activity of thiocyanate also awaits a robust explanation. In the last years, different types of experimental studies have shown that thiocyanate is capable to directly interact with both polar and nonpolar groups of polypeptide chains. This finding has been scrutinized via a careful computational procedure based on density functional theory approaches. The results indicate that thiocyanate is able to make H-bonds via both the nitrogen and sulfur atom, and to make strong van der Waals interactions with almost all the groups of polypeptide chains, regardless of their polarity.

Polyphenolic Composition and Antimicrobial, Antioxidant, Anti-Inflammatory, and Antihyperglycemic Activity of Different Extracts of Teucrium montanum from Ozren Mountain.

Teucrium montanum has widespread use in folk medicine on the Balkan peninsula. In order to scientifically justify this use, the composition and biological activity of aqueous, ethanol, and acetone extract were investigated in this study. Moreover, acetone and ethanol extracts were obtained from the plant material previously exhausted by water extraction. A total of 27 compounds were detected in extracts by UHPLC-DAD-MS/MS analysis, with all of them present in acetone and ethanol extracts. Consequentially, the acetone and ethanol extracts showed higher contents of total phenols of 23% and 18%, respectively, compared to the water extract. The results indicated high biological potential in the investigated extracts. Among all extracts, the aqueous extract showed slightly higher antimicrobial potential, especially against Gram-positive strains, probably due to the release of components soluble in water from the dry unexhausted plant material. On the other hand, the acetone and ethanol extracts had significantly higher antioxidative (by 20%), anti-inflammatory activity (up to 3 and 4 times higher, respectively), and α-glucosidase inhibitory potential (3 times higher) than the aqueous extract. The results of this investigation reveal the great potential of the use of T. montanum in various branches of food, cosmetics, and the pharmaceutical industry. An important part of this research is a confirmation that, once exhausted by water extraction, for example by hydrodistillation, T. montanum plant material can be reused for obtaining valuable products with a wide range of biological activities.

Adenosine monophosphate boosts the cryoprotection of ultrasound-assisted freezing to frozen surimi: Insights into protein structures and gelling behaviors.

Ultrasound-assisted freezing (UAF) is a clean technique for meat cryoprotections; however, its effectiveness is still limited compared to conventional cryoprotectants, e.g., sugars, polyols, especially at high dosages. To resolve this problem, a synergistic cryoprotection strategy was developed in this study. Adenosine monophosphate (AMP), an adenosine-type food additive, was introduced into frozen surimi at a considerably reduced content (0.08%), yet substantially enhanced the efficiency of UAF to comparable levels of commercial cryoprotectant (4% sucrose with 4% sorbitol). Specifically, UAF/AMP treatment retarded denaturation of surimi myofibrillar protein (MP) during 60-day frozen storage, as evidenced by its increased solubility, Ca2+-ATPase activity, sulfhydryl content, declined surface hydrophobicity, particle size, and stabilized protein conformation. Gels of UAF/AMP-treated surimi also demonstrated more stabilized microstructures, uniform water distributions, enhanced mechanical properties and water-holding capacities. This study provided a feasible approach to boost the cryoprotective performance of UAF, thus expanding its potential applications in frozen food industry.

Metabolomic profile of muscles from tilapia cultured in recirculating aquaculture systems and traditional aquaculture in ponds and protein stability during freeze-thaw cycles.

Muscle protein stability during freeze-thaw (F-T) cycles was investigated with tilapia cultured in recirculating aquaculture systems (RAS) and traditional aquaculture in ponds (TAP). This study found that fatty acids (eg., palmitic acid) were enriched in TAP, while antioxidants (eg., glutathione) were enriched in RAS. Generally, proteins in the RAS group exhibited greater stability against denaturation during the F-T cycle, suggested by a less decrease in haem protein content (77% in RAS and 86% in TAP) and a less increase in surface hydrophobicity of sarcoplasmic protein (63% in RAS and 101% in TAP). There was no significant difference in oxidative stability of myofibrillar protein between the two groups. This study provides a theoretical guide for the quality control of tilapia cultured in RAS during frozen storage.

Stabilizing effect of silver carp myofibrillar protein modified by high intensity ultrasound on high internal phase emulsions: Protein denaturation, interfacial adsorption and reconfiguration.

This study evaluated the impact of high intensity ultrasound (HIU) on myofibrillar proteins (MP) from silver carp, and investigated the stabilizing effect of HIU-treated MP (UMP) on high internal phase emulsions (HIPEs). Ultrasonic cavitation induced protein denaturation by decreasing size and unfolding conformation, to expose more hydrophobic groups, particularly UMP at 390 W, showing the smallest particle size (181.71 nm) and most uniform distribution. These structural changes caused that UMP under 390 W exhibited the highest surface hydrophobicity, solubility (92.72 %) and emulsibility (115.98 m2/g and 70.4 min), all of which contributed to fabricating stable HIPEs with oil volume fraction up to 0.8. UMP-based HIPEs possessed tightly packed gel network and self-supporting appearance due to the adsorption of numerous proteins at the oil-water interface and the reduction of interfacial tension by protein reconfiguration. The larger interface coverage reinforced cross-linking between interfacial proteins, thus increasing the viscoelasticity and recoverability of HIPEs, also the resistance to centrifugal force, high temperature (90 °C, 30 min) and freeze-thaw cycles. These findings furnished insightful perspectives for MP deep processing through HIU, expanding the high-value application of UMP-based HIPEs in fat replacer, nutritional delivery system with high encapsulation content and novel 3D printing ink.

Exploring the Therapeutic Potential of Ammodaucus leucotrichus Seed Extracts: A Multi-Faceted Analysis of Phytochemical Composition, Anti-Inflammatory Efficacy, Predictive Anti-Arthritic Properties, and Molecular Docking Insights.

Ammodaucus leucotrichus exhibits promising pharmacological activity, hinting at anti-inflammatory and anti-arthritic effects. This study investigated seed extracts from Ammodaucus leucotrichus using methanol and n-hexane, focusing on anti-inflammatory and anti-arthritic properties. The methanol extract outperformed the n-hexane extract and diclofenac, a reference anti-inflammatory drug, in trypsin inhibition (85% vs. 30% and 64.67% at 125 µg/mL). For trypsin inhibition, the IC50 values were 82.97 µg/mL (methanol), 202.70 µg/mL (n-hexane), and 97.04 µg/mL (diclofenac). Additionally, the n-hexane extract surpassed the methanol extract and diclofenac in BSA (bovine serum albumin) denaturation inhibition (90.4% vs. 22.0% and 51.4% at 62.5 µg/mL). The BSA denaturation IC50 values were 14.30 µg/mL (n-hexane), 5408 µg/mL (methanol), and 42.30 µg/mL (diclofenac). Gas chromatography-mass spectrometry (GC-MS) revealed 59 and 58 secondary metabolites in the methanol and n-hexane extracts, respectively. The higher therapeutic activity of the methanol extract was attributed to hydroxyacetic acid hydrazide, absent in the n-hexane extract. In silico docking studies identified 28 compounds with negative binding energies, indicating potential trypsin inhibition. The 2-hydroxyacetohydrazide displayed superior inhibitory effects compared to diclofenac. Further mechanistic studies are crucial to validate 2-hydroxyacetohydrazide as a potential drug candidate for rheumatoid arthritis treatment.

Antibody elution with 2-me/SDS solution: Uses for multi-layer immunohistochemical analysis of wholemount preparations of human colonic myenteric plexus.

Indirect immunofluorescence is usually restricted to 3-5 markers per preparation, limiting analysis of coexistence. A solution containing 2-mercaptoethanol and sodium dodecyl sulfate (2-ME/SDS) can elute indirect immunofluorescence labelling (i.e. primary antisera followed by fluorophore-conjugated secondary antisera) and has been used for sequential staining of sections. The aim of this study was to test whether 2-ME/SDS is effective for eluting indirect immunofluorescent staining (with primary antisera visualised by fluorophore-coupled secondary antisera) in wholemount preparations. We also analysed how 2-ME/SDS may work and used this understanding to devise additional uses for immunofluorescence in the nervous system. 2-ME/SDS appears to denature unfixed proteins (including antisera used as reagents) but has much less effect on antigenicity of formaldehyde-fixed epitopes. Moieties linked by strong biotin-streptavidin bonds are highly resistant to elution by 2-ME/SDS. Two primary antisera raised in the same species can be applied without spurious cross-reactivity, if a specific order of labelling is followed. The first primary antiserum is followed by a biotinylated secondary, then a tertiary of fluorophore-conjugated streptavidin. The preparation is then exposed to 2-ME/SDS, which has minimal impact on labelling by the first primary/secondary/tertiary combination. However, when this is followed by a second primary antiserum (raised in the same species), followed by a fluorophore-conjugated secondary antiserum, the intervening 2-ME/SDS exposure prevents cross-reactivity between primary and secondary antisera of the two layers. A third property of 2-ME/SDS is that it reduces lipofuscin autofluorescence, although it also raises background fluorescence and strongly enhances autofluorescence of erythrocytes. In summary, 2-ME/SDS is easy to use, cost-effective and does not require modified primary antisera. It can be used as the basis of a multi-layer immunohistochemistry protocol and allows 2 primary antisera raised in the same species to be used together.