Carbonyl Content Research Articles

Fluctuation of flavor quality in roasted duck: The consequences of raw duck preform’s repetitive freeze-thawing

This study aimed to investigate the changes in flavor quality of roasted duck during repetitive freeze-thawing (FT, −20 ℃ for 24 h, then at 4 ℃ for 24 h for five cycles) of raw duck preforms. HS-SPME/GC–MS analysis showed that more than thirty volatile flavor compounds identified in roasted ducks fluctuated with freeze-thawing of raw duck preforms, while hexanal, nonanal, 1-octen-3-ol, and acetone could as potential flavor markers. Compared with the unfrozen raw duck preforms (FT-0), repetitive freeze-thawing increased the protein/lipid oxidation and cross-linking of raw duck preforms by maintaining the higher carbonyl contents (1.40 ∼ 3.30 nmol/mg), 2-thiobarbituric acid reactive substances (0.25 ∼ 0.51 mg/kg), schiff bases and disulfide bond (19.65 ∼ 30.65 μmol/g), but lower total sulfhydryl (73.37 ∼ 88.94 μmol/g) and tryptophan fluorescence intensity. Moreover, A lower protein band intensity and a transformation from α-helixes to β-sheets and random coils were observed in FT-3 ∼ FT-5. The obtained results indicated that multiple freeze-thawing (more than two cycles) of raw duck preforms could be detrimental to the flavor quality of the roasted duck due to excessive oxidation and degradation.

Dietary salidroside supplementation improves meat quality and antioxidant capacity and regulates lipid metabolism in broilers

We aimed to explore the effect of salidroside (SAL) on meat quality, antioxidant capacity, and lipid metabolism in broilers. The results demonstrated that SAL significantly reduced the yellowness (b*), shear force, cooking loss, drip loss, MDA, TBARS, and carbonyl content in breast (P < 0.05), while increasing the pH value (P < 0.05), suggesting an improvement in meat quality. SAL lowered the lipid contents in liver and serum (P < 0.05), while increasing the proportion of unsaturated fatty acids in breast (P < 0.05), indicating effective regulation of lipid metabolism by SAL. SAL increased the activity of antioxidant enzymes and the expression of antioxidant genes in both liver and muscle (P < 0.05). Additionally, SAL improved the meat quality and antioxidant capacity of breast subjected to repeated freeze-thaw treatment. SAL may enhance meat quality by improving antioxidative stability and regulating lipid metabolism, potentially serving as a dietary supplement for broilers.

Theoretical exploration of the phenolic compounds’ inhibition mechanism of heterocyclic aromatic amines in roasted beef patties by density functional theory

The ability of spices (bay leaf, star anise, and red pepper) and their characteristic phenolic compounds (quercetin, kaempferol, and capsaicin) to inhibit Heterocyclic aromatic amines (HAAs) in roasted beef patties were compared. Density functional theory (DFT) was used to reveal phenolic compounds interacting with HAAs-related intermediates and free radicals to explore possible inhibitory mechanisms for HAAs. 3 % red chili and 0.03 % capsaicin reduced the total HAAs content by 57.09 % and 68.79 %, respectively. DFT demonstrated that this was due to the stronger interaction between capsaicin and the β-carboline HAAs intermediate (Ebind = –32.95 kcal/mol). The interaction between quercetin and phenylacetaldehyde was found to be the strongest (Ebind = −17.47 kcal/mol). Additionally, DFT indicated that capsaicin reduced the carbonyl content by transferring hydrogen atoms (HAT) to eliminate HO·, HOO·, and carbon-centered alkyl radicals. This study provided a reference for the development of DFT in the control of HAAs.

Correlations of dynamic changes in lipid and protein of salted large yellow croaker during storage

Protein and lipid are two major components that undergo significant changes during processing of aquatic products. This study focused on the protein oxidation, protein conformational states, lipid oxidation and lipid molecule profiling of salted large yellow croaker during storage, and their correlations were investigated. The degree of oxidation of protein and lipid was time-dependent, leading to an increase in carbonyl content and surface hydrophobicity, a decrease in sulfhydryl groups, and an increase in conjugated diene, peroxide value and thiobarbituric acid reactive substances value. Oxidation caused protein structure denaturation and aggregation during storage. Lipid composition and content changed dynamically, with polyunsaturated phosphatidylcholine (PC) was preferentially oxidized compared to polyunsaturated triacylglycerol. Correlation analysis showed that the degradation of polyunsaturated key differential lipids (PC 18:2_20:5, PC 16:0_22:6, PC 16:0_20:5, etc.) was closely related to the oxidation of protein and lipid. The changes in protein conformation and the peroxidation of polyunsaturated lipids mutually promote each other’s oxidation process.

Exploring the mechanism underlying the antifungal activity of chitosan-based ZnO, CuO, and SiO2 nanocomposites as nanopesticides against Fusarium solani and Alternaria solani

Chitosan-based nanocomposites (CS NCs) are gaining considerable attention as multifaceted antifungal agents. This study investigated the antifungal activity of NCs against two phytopathogenic strains: Fusarium solani (F. solani) and Alternaria solani (A. solani). Moreover, it sheds light on their underlying mechanisms of action. The NCs, CS-ZnO, CS-CuO, and CS-SiO2, were characterized using advanced methods. Dynamic and electrophoretic light scattering techniques revealed their size range (60–170 nm) and cationic nature, as indicated by the positive zeta potential values (from +16 to +22 mV). Transmission electron microscopy revealed the morphology of the NCs as agglomerates formed between the chitosan and oxide components. X-ray diffraction patterns confirmed crystalline structures with specific peaks indicating their constituents. Antifungal assessments using the agar diffusion technique demonstrated significant inhibitory effects of the NCs on both fungal strains (1.5 to 4-fold), surpassing the performance of the positive control, nystatin. Notably, the NCs exhibited superior antifungal potency, with CS-ZnO NCs being the most effective. A. solani was the most sensitive strain to the studied agents. Furthermore, the tested NCs induced oxidative stress in fungal cells, which elevated stress biomarker levels, such as superoxide dismutase (SOD) activity and protein carbonyl content (PCC), 2.5 and 6-fold for the most active CS-CuO in F. solani respectively. Additionally, they triggered membrane lipid peroxidation up to 3-fold higher compared to control, a process that potentially compromises membrane integrity. Laurdan fluorescence spectroscopy highlighted alterations in the molecular organization of fungal cell membranes induced by the NCs. CS-CuO NCs induced a membrane rigidifying effect, while CS-SiO2 and CS-ZnO could rigidify membranes in A. solani and fluidize them in F. solani. In summary, this study provides an in-depth understanding of the interactions of CS-based NCs with two fungal strains, showing their antifungal activity and offering insights into their mechanisms of action. These findings emphasize the potential of these NCs as effective and versatile antifungal agents.

Thermo-oxidative degradation behavior of natural rubber vulcanized by different curing systems

In this work, the effects of three types of curing systems: conventional vulcanization (CV), semi-efficient vulcanization (SEV) and efficient vulcanization (EV) on the degradation efficiency of sulfur cured natural rubber (NR) were investigated. NR vulcanizates were prepared and degraded at 210 °C in air for different periods of time. The sol fraction, molecular weight, element contents and degradation kinetics were studied in detail. The degradation efficiency of the NR vulcanizates was decreased in the order of CV, SEV and EV cured NR, which was caused by the lower crosslink density, apparent activation energy and bond dissociation energy of polysulfide bonds formed in the NR vulcanizates with CV, as compared to others. The results of Horikx theory and contents of carbonyl and sulfone group in degraded rubber indicated both sulfide scission and main chain scission occurred in the NR vulcanizates prepared with CV and SEV. Both the type of sulfidic crosslinks and crosslink density affect the degradative efficiency and products. The type of sulfidic crosslinks was the main factor affecting the degradation degree of NR vulcanizates, while the crosslink density mainly influenced the sol molecular weight of the degraded products. Moreover, the degradation mechanism of the three types of NR vulcanizates was proposed. This work demonstrated that the thermo-oxidative degradation efficiency of vulcanized rubber is affected by curing systems, which may provide guidance for upcycling waste rubber effectively.

Effect of three unsaturated fatty acids on the protein oxidation and structure of myofibrillar proteins from rainbow trout (Oncorhynchus mykiss)

In this study, the impact of three unsaturated fatty acids (Oleic acid: OA, Eicosapentaenoic acid: EPA, Docosahexaenoic acid: DHA) on the oxidation and structure of rainbow trout myofibrillar protein (MP) was explored. The findings revealed a notable increase in carbonyl content (P < 0.05) and a significant decrease in total sulfhydryl content (P < 0.05) of MP with the concentration increase of the three unsaturated fatty acids. Endogenous fluorescence spectroscopy and surface hydrophobicity analyses showed that unsaturated fatty acids can cause unfolding and exposure of hydrophobic groups in MP. In addition, SDS-PAGE showed that disulfide bonds were associated with MP cross-linking and aggregate size induced by unsaturated fatty acids. Overall, three unsaturated fatty acid treatments facilitated the oxidation of myofibrillar proteins, and the extent of protein oxidation was closely associated with the concentration of unsaturated fatty acids.

Effects of Different Phenolic Compounds on the Redox State of Myoglobin and Prevention of Discoloration, Lipid and Protein Oxidation of Refrigerated Longtail Tuna (Thunnus tonggol) Slices.

Effects of different phenolic compounds on the redox state of myoglobin and their potential for preserving the color and chemical quality of refrigerated longtail tuna (Thunnus tonggol) slices were studied. Purified myoglobin from dark muscle (15.83 kDa) was prepared. Catechin, EGCG, quercetin, and hyperoside affected the absorption spectra and redox state of metmyoglobin (metMb) at 4 °C for up to 72 h differently. Reduction of metMb to oxymyoglobin (oxyMb) was notably observed for two flavonols (EGCG and quercetin) at 50 and 100 ppm. Based on the reducing ability of metMb, EGCG and quercetin were selected for further study. Longtail tuna slices were treated with EGCG and quercetin at 200 and 400 mg/kg. Color (a* and a*/b*), proportion of myoglobin content, and quality changes were monitored over 72 h at 4 °C. Tuna slices treated with 200 mg/kg EGCG showed better maintenance of oxyMb and color as well as lower lipid oxidation (PV and TBARS) and protein oxidation (carbonyl content) than the remaining samples. Nevertheless, EGCG at 400 mg/kg exhibited lower efficacy in retaining the quality of tuna slices. Thus, EGCG at 200 mg/kg could be used to maintain the color and prolong the shelf life of refrigerated longtail tuna slices.

Effect mechanism of capsaicin and dihydrocapsaicin in chili on the oxidative stability of myoglobin in duck meat.

Myoglobin (Mb) in duck meat is commonly over-oxidized when heated at high temperatures, which may worsen the color of the meat. Enhancing the oxidative stability of Mb is essential for improving the color of duck meat. Capsaicin and dihydrocapsaicin (CA-DI) in chili exhibit antioxidant properties. This study investigated the effects of CA-DI on the structure and oxidative damage of Mb by fluorescence spectroscopy, differential scanning calorimetry analysis and particle size in duck meat during heat treatment. When the ratio of CA-DI to Mb was 10:1 g kg-1 and heat-treated for 36 min, oxymyoglobin significantly increased, and metmyoglobin significantly decreased compared with the control group (P < 0.05). In parallel, the carbonyl content of Mb in the CA-DI group decreased by 43.40 ± 0.10%, the sulfhydryl content increased by 188 ± 0.21%, and the free radical scavenging activity of Mb was significantly enhanced (P < 0.05). Moreover, the addition of CA-DI resulted in a significant decrease in the particle size of the Mb surface (P < 0.05). When the ratio of CA-DI to Mb was 10:1 g kg-1, CA-DI enhanced the thermal stability and significantly increased the thermal denaturation temperature of Mb. The molecular docking results indicated that hydrophobic interactions and hydrogen bonds were involved in the binding of CA-DI to Mb. CA-DI could combine with Mb and improve the oxidation stability of Mb in duck meat. This suggested that CA-DI could be a potential natural antioxidant that improves the color of meat products. © 2024 Society of Chemical Industry.

Assessing the impact of COVID-19 era drug combinations on hepatic functionality: A thorough investigation in adult Danio rerio

Current and thorough information on the ecotoxicological consequences of pharmaceuticals is accessible globally. However, there remains a substantial gap in knowledge concerning the potentially toxic effects of COVID-19 used drugs, individually and combined, on aquatic organisms. Given the factors above, our investigation assumes pivotal importance in elucidating whether or not paracetamol, dexamethasone, metformin, and their tertiary mixtures might prompt histological impairment, oxidative stress, and apoptosis in the liver of zebrafish. The findings indicated that all treatments, except paracetamol, augmented the antioxidant activity of superoxide dismutase (SOD) and catalase (CAD), along with elevating the levels of oxidative biomarkers such as lipid peroxidation (LPX), hydroperoxides (HPC), and protein carbonyl content (PCC). Paracetamol prompted a reduction in the activities SOD and CAT and exhibited the most pronounced toxic response when compared to the other treatments. The gene expression patterns paralleled those of oxidative stress, with all treatments demonstrating overexpression of bax, bcl2, and p53. The above suggested a probable apoptotic response in the liver of the fish. Nevertheless, our histological examinations revealed that none of the treatments induced an apoptotic or inflammatory response in the hepatocytes. Instead, the observed tissue alterations encompassed leukocyte infiltration, sinusoidal dilatation, pyknosis, fatty degeneration, diffuse congestion, and vacuolization. In summary, the hepatic toxicity elicited by COVID-19 drugs in zebrafish was less pronounced than anticipated. This attenuation could be attributed to metformin's antioxidant and hormetic effects.

Combined effect of cold plasma-activated oxygen (CPAO) and microwave on microbial decontamination and quality of milkshake powder

This study presents a new method combining cold plasma-activated oxygen (CPAO) and microwave (MW) to decontaminate milkshake powder, exploring its effectiveness, mechanisms, and quality impact. CPAO (6 min) alone reduced bacterial load by 0.419 log CFU/g, and MW (3 min) by 0.030 log CFU/g. However, their co-application significantly amplified decontamination, achieving a 1.265 log CFU/g reduction. CPAO-MW co-treatment inflicted more oxidative damage on bacterial cell membranes and intracellular antioxidant defense system, leading to higher mortality. It also raised protein and lipid oxidation, while decreasing vitamin C and A levels in the powder. Specifically, CPAO (6 min)-MW (3 min) co-treatment increased the carbonyl content from 0.438 to 0.891 nmol/mg protein, malondialdehyde from 0.824 to 0.996 mg/kg, and lowered vitamin C from 162.151 to 137.640 mg/kg, and vitamin A from 2.05 to 1.38 mg/kg. This study shows CPAO-MW is effective for decontaminating powdered foods but highlights a need to reduce negative effects.

Exploring the impact of malondialdehyde and 4-hydroxy-2-nonena on myofibrillar protein structure: A proteomic analysis

In this investigation, the impacts of malondialdehyde (MDA), 4-hydroxy-2-nonena (HNE), and their combinations on the structural characteristics of myofibrillar proteins (MP) were examined using endogenous fluorescence, Fourier transform infrared spectrum (FTIR) and Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE). The potential binding mechanisms were also explored using LC-MS/MS and proteomics techniques. The findings indicated that various reactive carbonyl compounds (RCCs) displayed distinct oxidation performances in the oxidation of myofibrillar proteins. Samples containing HNE (HMP and MHMP groups) exhibited a more pronounced ability to oxidize MP than those containing MDA, as evidenced by their higher carbonyl content and lower sulfhydryl content. The MHMP group demonstrated the greatest surface hydrophobicity and Schiff base content but the lowest fluorescence intensity, suggesting that MDA and HNE synergistically altered MP conformation. Moreover, the alteration by RCCs notably modified the secondary structure of MP. Among these, HMP triggered the unfolding of MP molecules, resulting in the lowest α-helix and highest β-sheet ratio. The SDS‒PAGE results suggested that MDA oxidation promoted the crosslinking of MP molecules. At the same time, HNE caused the degradation of MP, as indicated by the decrease in the intensity of the high-molecular-weight bands. Proteomic analysis suggested that lysine residues distributed in the tail region of myosin were the main binding sites for MDA, whereas HNE preferentially modified methionine located at the myosin head. Additionally, HNE-induced protein degradation dominated RCC-induced oxidation reactions. These findings provide deeper insights into the mechanisms underlying quality changes induced by lipid oxidation products in MP-based food systems.

Immunocompromisation of wheat host by L-BSO and 2,4-DPA induces susceptibility to the fungal pathogen Fusarium oxysporum

Susceptibility is defined as the disruption of host defence systems that promotes infection or limits pathogenicity. Glutathione (GSH) is a major component of defence signalling pathways that maintain redox status and is synthesised by γ-glutamyl cysteine synthetase (γ-ECS). On the other hand, lignin acts as a barrier in the primary cell wall of vascular bundles (VBs) synthesised by phenylalanine ammonia-lyase (PAL) in the intracellular system of plants. In this study, we used two inhibitors, such as L-Buthionine-sulfoximine (BSO), which irreversibly inhibits γ-ECS, and 2,4-dichlorophenoxyacetic acid (DPA), which reduces PAL activity and leads to the induction of oxidative stress in wheat (Triticum aestivum) seedlings after exposure to Fusarium oxysporum. Seedlings treated with 1 mM L-BSO and 2,4-DPA showed high levels of hydrogen peroxide (H2O2), malondialdehyde (MDA), carbonyl (CO) content, and low activity of antioxidative enzymes [superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and glutathione reductase (GR)] as compared to wild-type (WT) seedlings under F. oxysporum infection. Further, the content of reduced glutathione (RGSH), ascorbate (ASC), and lignin was decreased in BSO and DPA treated seedlings as compared to WT seedlings during Fusarium infection. Moreover, treatment with BSO and DPA significantly inhibited the relative activity of γ-ECS and PAL (P ≤ 0.001) in WT seedlings during Fusarium infection, which led to disintegrated VBs and, finally, cell death. Our results demonstrate that inhibition of γ-ECS and PAL by BSO and DPA, respectively, disrupts the defence mechanisms of wheat seedlings and induces susceptibility to F. oxysporum.

The Influence of a Commercial Few-Layer Graphene on the Photodegradation Resistance of a Waste Polyolefins Stream and Prime Polyolefin Blends

This work investigated the photostabilizing role of a commercially available few-layer graphene (FLG) in mixed polyolefins waste stream (MPWS), ensuring extended lifespan for outdoor applications. The investigation was conducted by analyzing carbonyl content increase, surface appearance, and the retention of mechanical properties of UV-exposed MPWS/FLG composites. Despite the likely predegraded condition of MPWS, approximately 60%, 70%, 80%, and 90% of the original ductility was retained in composites containing 1, 4, 7, and 10 wt.% FLG, respectively. Conversely, just 20% of the original ductility was retained in unfilled MPWS. Additionally, less crack density and lower carbonyl concentrations of the composites also highlighted the photoprotection effect of FLG. For prime polyolefin blends, only 0.5 wt.% or 1 wt.% FLG was sufficient to preserve the original surface finishing and protect the mechanical properties from photodegradation. Hence, it was observed that MPWS requires more FLG than prime polyolefin blends to get to comparable property retention. This could be attributed to the poor dispersion of FLG in MPWS and inevitable uncertainties such as the presence of impurities, pre-degradation, and polydispersity associated with MPWS. This study outlines a potential approach to revalorize MPWS that possess a minimal intrinsic value and would otherwise be destined for landfill disposal.

The halotolerant white sea anemone Anthothoe chilensis, highly abundant in brine discharges zones, as a promising biomonitoring species for evaluating the impacts of desalination plants

Seawater desalination raises concerns about its environmental repercussions, particularly the impact of brine discharge on benthic communities. In this study, we evaluated the effects of desalination and artificial brines on the sea anemone Anthothoe chilensis, following its observed proliferation near a brine outfall from a Chilean desalination plant. We measured biomarkers for oxidative stress (ROS content, lipid peroxidation, and protein carbonylation), antioxidant response (thiols), and osmotic stress (free amino acids and proline) in individuals collected from a brine discharge pipe (∼56 psu) and compared them to a population living in natural seawater salinity. Additionally, we conducted controlled laboratory experiments where A. chilensis specimens were exposed to a control salinity of 33 psu and to elevated salinities of 37 and 42 psu for 24 and 48 h. Results revealed a significant decrease in oxidative damage biomarkers, such as protein carbonylation and ROS content, along with an increase in free amino acids, proline, and thiols content at higher salinity levels, particularly under controlled conditions. These findings demonstrate the remarkable efficient cellular stress responses of this highly halotolerant species, which could potentially promote risky A. chilensis blooms in brine discharges areas. Additionally, this study provides valuable biomarker information for assessing the short-term impacts of brine discharges, which can be used in biomonitoring programs within the desalination sector.

Effect of plant polysaccharides on the conformation and gel properties of the Eugenol–Myofibrillar protein complex

This study investigated the effect of plant polysaccharides on the conformation and gel properties of the eugenol (Eu)-myofibrillar protein (MP) complex. Adding 0.5% inulin (I) and konjac glucomannan (K), which are two plant polysaccharides, to the Eu-MP complex lead to the inhibition of the Eu–MP interaction, which significantly increased carbonyl and thiol contents and surface hydrophobicity. Both polysaccharides significantly inhibited the reduction in the α-helix content (Eu-MP: 14.95%; Eu-MP-I: 18.04%; Eu-MP-K: 19.92%), thereby maintaining hydrogen bond stability in the protein. I and K significantly increased the strength of the complex gel and the storage modulus. Additionally, I and K promoted the formation of a denser gel structure of the Eu-MP complex, which significantly decreased moisture migration and the cooking loss of the gel. This study thus provides a theoretical basis for adding polysaccharide to inhibit the polyphenol–protein interaction so as to enhance the functional properties of proteins, as well as the practical application of polyphenols and polysaccharides in meat product processing.

Effect of low-frequency alternating magnetic fields on the physicochemical, conformational and rheological properties of myofibrillar protein after iterative freeze-thaw cycles

In this work, the effects of low-frequency alternating magnetic fields (LF-AMF) on the physicochemical, conformational, and functional characteristics of myofibrillar protein (MP) after iterative freeze-thaw (FT) cycles were explored. With the increasing LF-AMF treatment time, the solubility, active sulfhydryl groups, surface hydrophobicity, emulsifiability, and emulsion stability of MP after five FT cycles evidently elevated and then declined, and the peak value was obtained at 3 h. Conversely, the moderate LF-AMF treatment time can significantly reduce the average particle size, carbonyl content, and endogenous fluorescence intensity of MP. The rheology results showed that various LF-AMF treatment times would elevate the G' value of MP after iterative FT cycles. The FTIR spectroscopy results suggested that LF-AMF influenced the secondary structure of MP after multiple FT cycles, resulting in a depression in α-helix content and an increment in β-folding proportion. Moreover, LF-AMF treatment induced the gradually lighter and wider myosin heavy chain bands of MP, implying that LF-AMF accelerated the degradation of macromolecular aggregates. Therefore, the LF-AMF treatment efficaciously ameliorates the structural and functional deterioration of MP after iterative FT cycles and could be used as a potential quality-improving technology in the frozen meat industry.

Physicochemical and Morphological Properties of Litchi Seed Starch Oxidized by Different Levels of Sodium Hypochlorite

AbstractNon‐conventional starch sources have emerged as an interest due to their inherent physicochemical properties similar to conventional starches. This study aimed to enhance the value of non‐conventional litchi seed starch by employing anoxidizing process using different concentrations of sodium hypochlorite (NaOCl)(0.5, 1.5, 2.5, 3.5, 4.5%). The carbonyl and carboxyl content of oxidized starch was in the range of (0.019 – 0.323%) and (0.044 – 0.425%) showing an increase with the increasing concentration of NaOCl. The native and oxidized starches were further characterized for their functional and structural properties. The amylose content of native starch was 21.52% which was reduced to (19.34 – 13.43%) upon oxidation. The water and oil absorption capacities increased with theoxidation level. The swelling power(g/g) and solubility (g/100g) for native starch were 16.17 and 16.20 and 9.5 and 31.40 for modified starch. The oxidized starch produced clearer pastes. Scanning electron microscopy revealed surface erosion and cavities in oxidized starch granulesat higher concentrations. The oxidized starch showed higher relative crystallinity. FTIR was further used to assess structural changes in starches. Therefore, it can be concluded that oxidation significantly altered the characteristics of litchi seed starch, expanding its potential applications in various industries.

Application of the Effect of Nonthermal Technologies on the Oxidation of Proteins and Lipids in Pigeon Meat during Chilled Storage

This study investigated the effects of low-voltage electrostatic field (LVEF), electron beam irradiation (EBI), and modified atmosphere packaging (MAP) on protein and lipid oxidation of pigeon meat (PM) during chilled storage. The water-holding capacity (WHC) and color reflected that the difference between the LVEF-treated (1.20 kV/m) group and the fresh groups was the smallest. The oxidation analysis of protein showed that the LVEF-treated group had smaller values of carbonyl concentration (0.0551 ± 0.0048 μmol/g), larger values of sulfhydryl concentration (0.737 ± 0.0364 μmol/g), and higher Ca2+-ATPase activity (30.10 ± 1.52 U/g) than the C4 group (0.0649 ± 0.0013 μmol/g, 0.510 ± 0.0225 μmol/g, and 25.18 ± 1.42 U/g, respectively). SDS-PAGE demonstrated the ability of LVEF to inhibit the hydrolysis and cross-linking of proteins. Meanwhile, the LVEF-treated group had lower values of TBARs (2.26 ± 0.0371 μg/kg) than the other groups and had a lower lipid oxidation level. In addition, the fatty acids in the LVEF-treated group were similar to those in the fresh group and were beneficial to human health. In conclusion, LVEF (1.20 kV/m) could inhibit protein and lipid oxidation of PM during chilled storage.

Citric acid crosslinked carboxymethyl cellulose edible films: A case study on preserving freshness in bananas

The study involves the preparation and characterization of crosslinked-carboxymethyl cellulose (CMC) films using varying amounts of citric acid (CA) within the range 5 %–20 %, w/w, relative to the dry weight of CMC. Through techniques such as Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, carbonyl content analysis, and gel fraction measurements, the successful crosslinking between CMC and CA is confirmed. The investigation includes an analysis of chemical structure, physical and optical characteristics, swelling behavior, water vapor transmission rate, moisture content, and surface morphologies. The water resistance of the cross-linked CMC films exhibited a significant improvement when compared to the non-crosslinked CMC film. The findings indicated that films crosslinked with 10 % CA demonstrated favorable properties for application as edible coatings. These transparent films, ideal for packaging, prove effective in preserving the quality and sensory attributes of fresh bananas, including color retention, minimized weight loss, slowed ripening through inhibiting amyloplast degradation, and enhanced firmness during storage.