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Proteins and essential fatty acids are crucial components of the human diet. However, lipids and proteins are susceptible to oxidative modification during food processing resulting in changes to their structural characteristics and functional properties. Food products rich in polyunsaturated fatty acids are highly susceptible to lipid peroxidation and generate bifunctional reactive aldehydes. Bifunctional aldehydes such as malondialdehyde (MDA), 4-hydroxy-2-nonenal (4-HNE), and 4-oxo-2-nonenal (4-ONE) readily bind to protein nucleophiles and lead to intra- or intermolecular protein cross-linking. In comparison with lipid oxidation, the degradation of proteins by prooxidants appears to be more intricate and results in a greater diversity of oxidation products. Although individual oxidation processes involving lipids and proteins received increasing attention in the past decades, the interactions between those aldehydes and protein oxidation in food have not been extensively explored. Studies indicate that the reactions of lipid and protein oxidation may take place simultaneously or independently, but oxidation products that arose from one reaction may further interact with lipids or proteins. The present review presents a perspective on reactive aldehydes and the role of aldehydes in inducing protein oxidation in muscle foods. Emphasis is focused on the interaction mechanism of the lipid, protein, and myoglobin protein oxidations. In addition, the occurrence of aldehydes derived from lipid oxidation in food systems as well as the endogenous antioxidant peptides or amino acids in meat and plant proteins are also briefly described. [ABSTRACT FROM AUTHOR]

Summary: This study aimed to investigate the effects of different oxidation modes on the functional and gel properties of hazelnut proteins. The solubility of hazelnut protein showed a small trend when the oxidation level was low, and it decreased significantly with the increase in concentration. The maximum value of water‐holding capacity (WHC), emulsifying activity index (EAI), and emulsion stability index (ESI) was 343.33%, 56.00 m2 g−1, and 75.85 min at AAPH concentration of 1.0 mmol L−1, respectively. The functional properties of hazelnut proteins, except oil‐holding capacity (OHC), gradually reduced with the increase in malondialdehyde (MDA) concentration. H2O2 modified improved OHC, foaming capacity, foam stability, and EAI of hazelnut proteins, whereas WHC and ESI gradually decreased. The results of the secondary structure of hazelnut protein gels indicated a high ratio of α‐helix and β‐fold of the gels. Also, the increase in oxidation led to an increase in the gels' voids. Also, oxidation led to a rough and loose network structure of hazelnut protein gels. These results suggested that peroxyl radical, hydroxyl radical, and MDA produced during lipid peroxidation affected the interfacial properties of hazelnut protein and disrupted the formation of hazelnut protein gel, thus affecting the quality of hazelnut protein. [ABSTRACT FROM AUTHOR]

Objective: This study investigated the protein oxidation of soybean meal (SBM) stored in a warehouse and the effects of SBM on growth performance, antioxidant status, digestive performance, intestinal morphology, and breast muscle quality of broilers. Methods: In total, 160 one-day-old Arbor Acres Plus broilers (half male and half female) were randomly divided into two groups with ten replicates of eight birds each: The control group was served with a basal diet including SBM stored at –20°C (FSBM), and the experimental group was served with a basal diet including SBM stored in a warehouse at room temperature for 45 days (RSBM). Results: Compared with FSBM, the protein carbonyl level in RSBM was increased, the free and total thiol levels and in vitro digestibility of protein were decreased. The RSBM decreased the serum glutathione (GSH) level and the hepatic total superoxide dismutase (T-SOD) activity at days 21 and 42 when compared with FSBM. Further, RSBM reduced the duodenal T-SOD activity, jejunal catalase (CAT), and T-SOD activities at day 21, and decreased the duodenal CAT and T-SOD activities, jejunal T-SOD activity, and ileal GSH level and T-SOD activity at days 21 and 42 when compared with FSBM. Besides, the trypsin activity and the ratio of villus height to crypt depth in small intestines of broilers at days 21 and 42 were reduced when fed with a RSBM-contained diet. Compared with FSBM, the 24-h drip loss, shear force, and 24- and 48-h cooking loss of breast muscle were increased of RSBM group, the opposite result was observed for muscle lightness at 48 h. Conclusion: Room temperature storage for 45 days led a protein oxidation and decreased in vitro digestibility in SBM, and fed RSBM impaired growth performance, antioxidant status, and meat quality, reduced trypsin activity, and affected the small intestine morphology in broilers. [ABSTRACT FROM AUTHOR]

Evaluating protein and mitochondrial alterations post‐mortem can contribute to determining correlations between fish‐processing parameters and ultimate fish muscle quality. The myofibrillar protein alteration during rigor mortis directly affects the texture of fish muscle. To identify the mechanisms behind post‐mortem softness and quality deterioration, it is crucial to understand the conditions linked to the breakdown of myofibrillar proteins in fish skeletal muscle. Therefore, monitoring protein breakdown at the molecular level and finding target proteins would be considered a marker for fish freshness. Mitochondria play an important role in executing and regulating cell death processes, including apoptosis and necrosis. The mitochondria are the seat of cellular respiration and experience significant alterations in post‐mortem tissues. Processes used to reduce protein degradation, such as optimizing chilling and handling practices, would also minimize mitochondrial changes in fillet quality. Moreover, pH fluctuations are considered a critical point that influences both protein and mitochondrial changes. This review considered the implications of protein and mitochondrial alteration during post‐mortem storage in fish fillets and the possible pathways of their interaction on fillet quality. Mitochondrial characteristics, such as membrane integrity, pH, and ATP levels, are important for post‐mortem muscle cell changes, serving as an early indicator of fish freshness. Understanding the mechanisms behind protein degradation in fish muscle led to maintaining fillet quality and requires further experiments. Label‐free proteomics combined with bioinformatics is crucial for comprehending protein degradation mechanisms to provide customers with safe and fresh fish products while minimizing economic losses associated with fillet deterioration. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The large multi-subunit mitochondrial alpha-keto glutarate dehydrogenase (KGDH) complex plays a key, rate-determining, role in the tricarboxylic acid (Krebs) cycle, catalyzing the conversion of alpha-keto glutarate to succinyl-CoA. This complex is both a source and target of oxidants, but the sites of modification and association with structural changes and activity loss are poorly understood. We report here oxidative modifications induced by Rose Bengal (RB) in the presence of O 2 , a source of singlet oxygen (1O 2). A rapid loss of activity was detected, with this being dependent on light exposure, illumination time, and the presence of RB and O 2. Activity loss was enhanced by D 2 O (consistent with 1O 2 involvement), but diminished by both pre- and (to a lesser extent) post-illumination addition of lipoic acid and lipoamide. Aggregates containing all three KGDH subunits were detected on photooxidation. LC-MS experiments provided evidence for oxidation at 45 sites, including specific Met, His, Trp, Tyr residues and the lipoyllysine active-site cofactor. Products include mono- and di-oxygenated species, and kynurenine from Trp. Mapping of the modifications to the 3-D structure showed that these are localized to both the inner channel and the external surface, consistent with reactions of free 1O 2 , however the sites and extent of modification do not correlate with their solvent accessibility. These products are generated concurrently with loss of activity, indicative of strong links between these events. These data provide evidence for the impairment of KGDH activity by 1O 2 via the oxidation of specific residues on the protein subunits of the complex. [Display omitted] • α-Ketoglutarate dehydrogenase complex is a rate-determining enzyme in the tricarboxylic acid (Krebs) cycle. • Photooxidation and 1O 2 formation results in photolysis time- and O 2 -dependent loss of activity. • Protein side-chain modifications were detected by LC-MS and aggregation by SDS-PAGE. • Modifications detected at 45 sites including Met, Trp, His, Tyr residues and the lipoic acid active-site cofactor. • Widespread damage occurs on all of the complex subunits, consistent with reactions of free 1O 2. [ABSTRACT FROM AUTHOR]

Rohu fish (Labeo rohita) fillets were coated with 2.5% to 25% soy protein isolate (SPI) to evaluate their ability to reduce fat uptake. The coating pickup of fish fillets increased with increasing coating concentration. Fillets coated with 15% SPI showed the highest coating pickup value of 18.29% and reduced fat uptake by 57.78%. As revealed by lowered carbonyl and sulfhydryl contents, SPI coating protected proteins from oxidation during deep-frying. Increasing coating concentration decreased the hardness, chewiness, and cutting force of coated fish fillets. Therefore, the aforesaid coatings could be recommended for making low-fat fried fish fillets with 15% SPI. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND RESULTS CONCLUSION Natural polyphenols offer a safer alternative to synthetic antioxidants in meat products. This study investigated the efficacy of green tea and black tea extracts as natural antioxidants in Cantonese sausages to inhibit lipid and protein oxidation.Sausages were prepared with the addition of different concentrations – 100, 300, and 600 mg kg−1 total polyphenols (TP) – of green tea or black tea extract. Oxidation of the sausages was assessed through thiobarbituric acid reactants, carbonyl content, and thiol content, whereas consumer acceptability was evaluated based on texture, color, and sensory analysis. The tea extracts inhibited malondialdehyde production and reduced the thiobarbituric acid reactive substance value from 23.72 mmol MDA g−1 to less than 1.94 mmol MDA g−1. However, the addition of tea extracts decreased the thiol content and caused the loss of myosin heavy chain and actin bonds in sodium dodecyl sulfate polyacrylamide gel electrophoresis. Although the addition of tea extracts increased the redness and hardness of the sausage, no significant difference in consumer acceptance between the control and treatment groups was observed in the sensory analysis.The tea extract inhibited the oxidation of lipids in Cantonese sausage. There was no negative effect on the sensory characteristics of sausages. The use of tea extracts as natural antioxidants in Cantonese sausage is therefore feasible. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Summary: The effect of dry aging process (15 and 30 days) on some quality parameters, protein profile and formation of protein oxidation products of beef was investigated. The maximum weight and trim loss were calculated to be 47.07% and 23.06%, respectively. The meat dry‐aged for 30 days had higher dry matter, pH and protein content, but lower L* and a* values than those of the unaged meats. There was a significant decrease in actin protein band density in the meat dry‐aged for 30 days and a new protein band of 32 kDa appeared in the myofibrillar protein fraction. The dry aging process caused an insignificant increase in the total carbonyl content (P > 0.05). However, the γ‐glutamic semialdehyde (GGS), α‐aminoadipic semialdehyde (AAS) and total GGS and AAS contents were higher in the dry‐aged meats for 30 days. Total GGS and AAS contents ranged from 15.36% to 31.87% of the total carbonyl content. It was found that there was no significant difference between control group (unaged) meats and the meat dry‐aged for 15 days in terms of protein oxidation products. [ABSTRACT FROM AUTHOR]

Protein peroxidation during the storage and processing of aquatic products has a great impact on the nutritional value, sensory quality, textural properties and protein functional properties of aquatic products. Natural spice extracts can not only impart flavor to aquatic products, but also show good antioxidant properties in the processing and storage of aquatic products. In order to provide theoretical support for expanding the application of spice extracts and for optimizing the processing of aquatic products, this paper elucidates the molecular mechanism of protein oxidation, the major components of spice extracts and their mechanism of action in delaying protein peroxidation, and summarizes the application of spice extracts in reducing protein oxidation in aquatic products.

The effect of addition of different levels of lotus leaf powder on the flavor of dried minced pork slices (DMPS) was studied by examining its sensory flavor attributes, flavor substances, lipid and protein oxidation levels, Maillard reaction degree, and microstructure. The results showed that addition of lotus leaf powder significantly affected the flavor of DMPS. Addition of lotus leaf powder at 0.2% and 0.4% improved the flavor of DMPS by inhibiting the oxidation of lipids and proteins and consequently reducing the contents of the fat rancidity flavor compounds hexanal and nonanal, and the fishy odor compound trimethylamine. The generation of phenethyl alcohol, (E)-2-hexenal, and methyl acetate provided DMPS with a delicate fragrance of lotus. However, adding 0.6% or 0.8% lotus leaf powder significantly decreased the contents of sweet amino acids and the umami taste intensity of DMPS, and exacerbated lipid and protein oxidation by disrupting the microstructure of DMPS. Furthermore, lotus leaf powder suppressed the production of volatile heterocyclic compounds in DMPS by inhibiting the Maillard reaction. Therefore, addition of an appropriate amount of lotus leaf powder could effectively improve the flavor of DMPS.

Meat is an important part of the daily human diet, and its quality is essential for consumers' health and taste experience. During the transformation from carcass to meat and meat processing after animal slaughter, many complex biochemical reactions occur, among which protein oxidation plays an important role in the formation of meat quality. Based on the influence of protein oxidation on meat quality, the relationship between protein oxidation and changes in meat quality under factors such as the types of protein oxidation products, processing methods and conditions is summarized in this review, which will provide a theoretical basis for reducing the oxidation of meat protein, and a scientific guidance for practical production.

The oxidative phase of the pentose phosphate pathway (PPP) involving the enzymes glucose-6-phosphate dehydrogenase (G6PDH), 6-phosphogluconolactonase (6PGL), and 6-phosphogluconate dehydrogenase (6PGDH), is critical to NADPH generation within cells, with these enzymes catalyzing the conversion of glucose-6-phosphate (G6P) into ribulose-5-phosphate (Ribu5-P). We have previously studied peroxyl radical (ROO•) mediated oxidative inactivation of E. coli G6PDH, 6PGL, and 6PGDH. However, these data were obtained from experiments where each enzyme was independently exposed to ROO•, a condition not reflecting biological reality. In this work we investigated how NADPH production is modulated when these enzymes are jointly exposed to ROO•. Enzyme mixtures (1:1:1 ratio) were exposed to ROO• produced from thermolysis of 100 mM 2,2′-azobis(2-methylpropionamidine) dihydrochloride (AAPH). NADPH was quantified at 340 nm, and protein oxidation analyzed by liquid chromatography with mass spectrometric detection (LC-MS). The data obtained were rationalized using a mathematical model. The mixture of non-oxidized enzymes, G6P and NADP+ generated ∼175 μM NADPH. Computational simulations showed a constant decrease of G6P associated with NADPH formation, consistent with experimental data. When the enzyme mixture was exposed to AAPH (3 h, 37 °C), lower levels of NADPH were detected (∼100 μM) which also fitted with computational simulations. LC-MS analyses indicated modifications at Tyr, Trp, and Met residues but at lower concentrations than detected for the isolated enzymes. Quantification of NADPH generation showed that the pathway activity was not altered during the initial stages of the oxidations, consistent with a buffering role of G6PDH towards inactivation of the oxidative phase of the pathway. [Display omitted] • G6PDH, 6PGL and 6PGDH are enzymes of the oxidative phase of the pentose phosphate pathway. • NADPH generation was quantified when these enzymes are jointly exposed to ROO•. • Protein damage was studied by LC-MS and a mathematical model used to rationalize results. • Simulated and experimental data showed reduced NADPH levels in the presence of ROO•. • Results suggest a buffering role of G6PDH against ROO• mediated inactivation. [ABSTRACT FROM AUTHOR]

Methionine is an essential amino acid for mammals and it is limiting for monogastric animals. It can be oxidized easily by UV light. This could influence the bioaccessibility and bioavailability of methionine. In this work, the photosensitized degradation of peptide-bound methionine in the presence of riboflavin was investigated in a model system. Capillary electrophoresis was employed to analyze the time course of the degradation. The products were identified by liquid chromatography coupled to mass spectrometry (LC–MS/MS). Benzoyl methionine was degraded by 50% during UV irradiation in the presence of riboflavin after 5.0 min with 10 mol% riboflavin and 6.4 min with 3 mol% riboflavin. Homocysteine (16–20 mol%) and β-aspartic semialdehyde (ca. 30 mol%) were found as major degradation products next to methionine sulfoxide (ca. 25 mol%). A smaller molar ratio of riboflavin led to a higher formation of aspartic semialdehyde. The formation of homocysteine was paralleled by the formation of formaldehyde. Furthermore, the experiment was transferred to small peptides, which showed the analogous degradation products of peptide-bound methionine. [ABSTRACT FROM AUTHOR]

Despite of yet unknown mechanism, microvascular deposition of oligomeric Tau (oTau) has been implicated in alteration of the Blood-Brain Barrier (BBB) function in Alzheimer's disease (AD) brains. In this study, we employed an in vitro BBB model using primary mouse cerebral endothelial cells (CECs) to investigate the mechanism underlying the effects of oTau on BBB function. We found that exposing CECs to oTau induced oxidative stress through NADPH oxidase, increased oxidative damage to proteins, decreased proteasome activity, and expressions of tight junction (TJ) proteins including occludin, zonula occludens-1 (ZO-1) and claudin-5. These effects were suppressed by the pretreatment with Fasudil, a RhoA/ROCK signaling inhibitor. Consistent with the biochemical alterations, we found that exposing the basolateral side of CECs to oTau in the BBB model disrupted the integrity of the BBB, as indicated by an increase in FITC-dextran transport across the model, and a decrease in trans endothelial electrical resistance (TEER). oTau also increased the transmigration of peripheral blood mononuclear cells (PBMCs) in the BBB model. These functional alterations in the BBB induced by oTau were also suppressed by Fasudil. Taken together, our findings suggest that targeting the RhoA/ROCK pathway can be a potential therapeutic strategy to maintain BBB function in AD. [Display omitted] • Oligomeric Tau (oTau) induces oxidative stress and impairs function in cerebral endothelial cells. • Inhibition of the RhoA/ROCK pathway mitigates the effects of oTau on CECs. • Targeting the Rho/ROCK pathway can be therapeutic strategy to maintain blood-brain barrier function in Alzheimer's disease. [ABSTRACT FROM AUTHOR]

Simple Summary: The protein oxidation of soybean meal, resulting from storage, can detrimentally impact the intestinal digestive and absorptive functions in animals. Meanwhile, quercetin can regulate protein and lipid metabolism, intestinal transporter numbers, and gut microbiota in animals. The aim of this study was to investigate the effect of quercetin supplementation on the intestinal digestive and absorptive functions and microbiota in rats fed protein-oxidized soybean meal. The results of this study indicated that the protein-oxidized soybean meal decreased the relative weights of the digestive organs and the duodenal villus height, thereby reducing the apparent ileal digestibility of amino acids in the rats. Transcriptomics and microbiomics revealed that quercetin supplementation alleviated these adverse effects primarily by upregulating the pathway of intestinal amino acid transmembrane transporter activity and improving the cecal microbial composition. To clarify the nutritional mechanisms of quercetin mitigation in the digestive and absorptive functions in rats fed protein-oxidized soybean meal, 48 three-week-old male SD rats were randomly allocated into a 2 × 2 factorial design with two soybean meal types (fresh soybean meal or protein-oxidized soybean meal) and two quercetin levels (0 or 400 mg/kg) for a 28-day feeding trial. The protein-oxidized soybean meal treatment decreased (p < 0.05) the relative weights of the pancreas, stomach, and cecum, duodenal villus height, pancreatic and jejunal lipase activities, apparent ileal digestibility of amino acids, and apparent total tract digestibility of dry matter, crude protein, and ether extract. The supplementation of quercetin in the protein-oxidized soybean meal diet reversed (p < 0.05) the decreases in the duodenal length, ileal villus height, lipase activity, apparent ileal digestibility of amino acids, and apparent total tract digestibility of dry matter, crude protein, and ether extract. Transcriptomics revealed that the "alanine transport" and "lipid digestion and absorption" pathways were downregulated by the protein-oxidized soybean meal compared with fresh soybean meal, while the "basic amino acid transmembrane transporter activity" and "lipid digestion and absorption" pathways were upregulated by the quercetin supplementation. Microbiomics revealed that the protein-oxidized soybean meal increased the protein-degrading and inflammation-triggering bacteria in the cecum, while the relative abundances of beneficial bacteria were elevated by the quercetin supplementation. [ABSTRACT FROM AUTHOR]

Heavy metal pollution is a serious environmental problem. Most of the current techniques used to mitigate the toxic effects of heavy metals have limitations. This creates an urgent need to explore safer and more efficient methods to address these toxic effects. This study investigates the potential of nano-water hyacinth protein (nano-WHP) as an adsorbent and soil amendment to mitigate cadmium pollution. Nano-WHP is derived from water hyacinth protein and immobilized on nano-chitosan. The Cd adsorption capacity and removal efficiency of nano-WHP were determined. Nano-WHP was applied as a soil amendment to examine its impact on soil enzyme activity and the growth of common bean plants under Cd stress. Nano-WHP could remove 96% of Cd with an adsorption capacity of 150 mg Cd g⁻1. When used as a soil amendment under Cd stress, nano-WHP positively influenced soil enzyme activity, enhancing soil health and promoting the growth of common bean plants. The growth of nano-WHP-treated plants increased by approximately 35% and 50% in the first and second stages, respectively, compared to the control group under cadmium stress. Furthermore, nano-WHP significantly reduced oxidative stress markers such as lipid peroxidation, DNA oxidation, protein oxidation, and H₂O₂ levels, with reductions of about 90.63%, 85.13%, 79.35%, and 81.85%, respectively, compared to untreated plants. This reduction in oxidative stress markers is attributed to the lower availability of Cd and the heightened activity of the antioxidant machinery in nano-WHP-treated plants. These results establish a foundation for the formulation of sustainable and economically feasible methodologies to mitigate Cd contamination. [ABSTRACT FROM AUTHOR]

At inflammatory sites, immune cells generate oxidants including H₂O₂. Myeloperoxidase (MPO), released by activated leukocytes employs H₂O₂ and halide/pseudohalides to form hypohalous acids that mediate pathogen killing. Hypochlorous acid (HOCl) is a major species formed. Excessive or misplaced HOCl formation damages host tissues with this linked to multiple inflammatory diseases. Previously (Redox Biology , 2020, 28, 101331) we reported that iodide (I⁻) modulates MPO-mediated protein damage by decreasing HOCl generation with concomitant hypoiodous acid (HOI) formation. HOI may however impact on protein structure, so in this study we examined whether and how HOI, from peroxidase/H₂O₂/I⁻ systems ± Cl⁻, modifies proteins. Experiments employed MPO and lactoperoxidase (LPO) and multiple proteins (serum albumins, anastellin), with both chemical (intact protein and peptide mass mapping, LC-MS) and structural (SDS-PAGE) changes assessed. LC-MS analyses revealed dose-dependent iodination of anastellin and albumins by LPO/H 2 O 2 with increasing I⁻. Incubation of BSA with MPO/H 2 O 2 /Cl⁻ revealed modest chlorination (Tyr286, Tyr475, ∼4 %) and Met modification. Lower levels of these species, and extensive iodination at specific Tyr and His residues (>20 % modification with ≥10 μM I⁻) were detected with increasing I⁻. Anastellin dimerization was inhibited by increasing I⁻, but less marked changes were observed with albumins. These data confirm that I⁻ competes with Cl⁻ for MPO and is an efficient HOCl scavenger. These processes decrease protein chlorination and oxidation, but result in extensive iodination. This is consistent with published data on the presence of iodinated Tyr on neutrophil proteins. The biological implications of protein iodination relative to chlorination require further clarification. [Display omitted] • Peroxidases, such as myeloperoxidase (MPO) damage proteins as sites of inflammation. • Iodide (I−) modulates MPO-induced protein damage and inhibits cross-linking. • Low I− levels cause a dramatic switch from methionine to tyrosine (Tyr) modification. • Hypoiodous acid (HOI) exposure results in selective Tyr and His iodination. • HOI induces only minor gross structural changes but enhances protein hydrophobicity. [ABSTRACT FROM AUTHOR]

Summary: The study inquired the influences of l‐arginine and l‐lysine on the physicochemical properties (including weight loss rate, water activity, texture, colour, lipid and protein oxidation, residual nitrite content and total volatile basic nitrogen (TVB‐N) content) of low‐sodium and low‐phosphate Cantonese sausage during the 1‐ and 7‐day storage. The results showed that the addition of l‐arginine or l‐lysine reduced the weight loss rate, TBARS content, carbonyl group content and residual nitrite level, slightly decreased water activity, and enhanced L*, a* and b* values. Compared to the control, 0.3% l‐arginine or l‐lysine declined hardness and chewiness, while 0.6% l‐arginine or l‐lysine elevated these two parameters. However, the addition of l‐arginine or l‐lysine also led to an increase in TVB‐N content. Overall, l‐arginine and l‐lysine improved the qualities of low‐sodium and low‐phosphate Cantonese sausage, which might be attractive to meat product manufacturers. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Chinese Institute of Food Science & Technology / Zhongguo Shipin Xuebao is the property of Journal of Chinese Institute of Food Science & Technology Periodical Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Cold plasma treatment is an innovative technology in the food processing and preservation sectors. It is primarily employed to deactivate microorganisms and enzymes without heat and chemical additives; hence, it is often termed a "clean and green" technology. However, food quality and safety challenges may arise during cold plasma processing due to potential chemical interactions between the plasma reactive species and food components. This review aims to consolidate and discuss data on the impact of cold plasma on the chemical constituents and physical and functional properties of major food products, including dairy, meat, nuts, fruits, vegetables, and grains. We emphasize how cold plasma induces chemical modification of key food components, such as water, proteins, lipids, carbohydrates, vitamins, polyphenols, and volatile organic compounds. Additionally, we discuss changes in color, pH, and organoleptic properties induced by cold plasma treatment and their correlation with chemical modification. Current studies demonstrate that reactive oxygen and nitrogen species in cold plasma oxidize proteins, lipids, and bioactive compounds upon direct contact with the food matrix. Reductions in nutrients and bioactive compounds, including polyunsaturated fatty acids, sugars, polyphenols, and vitamins, have been observed in dairy products, vegetables, fruits, and beverages following cold plasma treatment. Furthermore, structural alterations and the generation of volatile and non‐volatile oxidation products were observed, impacting the color, flavor, and texture of food products. However, the effects on dry foods, such as seeds and nuts, are comparatively less pronounced. Overall, this review highlights the drawbacks, challenges, and opportunities associated with cold plasma treatment in food processing. [ABSTRACT FROM AUTHOR]

In this study, the nutraceutical properties of ethanolic extract of Hyeronima macrocarpa fruits, immobilized on nanocellulose-based aerogels (NCAG) synthesized from the seeds were studied. Specifically, bioactives with antioxidant properties of the pulp were determined, NCAG and homologs of acetate (NCAG-A) and sulfate (NCAG-S) were obtained, and characterized from the seed, the aerogels loaded with antioxidants were studied to determine the anti-radical activity, digestion patterns, protein oxidation inhibition, and toxicological properties. The berries presented a high anthocyanin content of 1317.4 mg C3G/100 g FW and ORAC value ​​of 12,732 µmol Trolox/100 g FW, which make an important source of antioxidants. The seeds presented cellulose content of 61.4 % with a NC yield of 38.4 %. NCAG and their surface homologs were successfully synthesized and characterized by FTIR, DLS, and TEM finding the characteristic bands of the main functional groups, NC presented particle sizes ranging from 64 to 141 nm, BET analysis showed surface areas of 71.1, 102.3, and 183.5 m2/g for NCAG-A, NCAG, and NCAG-S, respectively, and pore sizes of 36–38 nm called mesopores. NCAG presented the highest capacity to trap reactive oxygen species (106.8 mg catechin Eq./g., 86.5 % OH• trapped, respectively). All samples showed the capacity to delay the oxidation of a protein system in a dose-dependent manner, with IC50 values ​​of 70 mg/L (NCAG), 176.3 mg/L (NCAG-A), and 255.6 mg/L (NCAG-S). In vitro digestion showed that NCAG-S was more efficient in delivering anthocyanins under gastric conditions (bioaccessibility of 59.3 %), and NCAG under duodenal conditions (bioaccessibility of 88.2 %). The differences found in samples for the different functional assays can be explained by the various types of interactions generated between the antioxidant molecules and aerogels, in the various media where the analyses are carried out. The results indicate nanocellulose-based aerogels, synthesized from lignocellulosic residues of H. macrocarpa seeds, proved to be porous matrices capable of carrying bioactive substances, and presented interesting properties for the delivery and conservation of antioxidant molecules such as anthocyanins and other polyphenols, achieving an in vitro protective effect against the oxidation of biomolecules.

This work systematically investigated the effects of pre-slaughter transport stress on pork water holding capacity (WHC) during aging from the perspectives of oxidation, structure, function, and degradation properties of protein. Pigs were randomly divided into three-hour transport (Transport-induced stress, T group) and three-hour transport followed by three-hour resting (Control, TR group). Results demonstrated that T treatment markedly declined pork WHC. Compared with TR group, T group presented increased oxidation levels. Meanwhile, T treatment exacerbated the shift of protein secondary structure from α-helix to random coil and protein unfolding levels. The decreased solubility, thermal stability, and degraded levels of proteins were also observed in T group. Additionally, muscle contractions of T group were more severe than TR group. This study supported that pre-slaughter transport stress altered physicochemical properties and structures of postmortem muscle proteins, which reduced pork WHC via impairing the interactions between protein and water molecules and changing the muscle fiber structure.

This study investigated the effect of clove essential oil used prior to stunning by cranial percussion and hypothermia on Nile tilapia (Oreochromis niloticus) welfare and fillet quality. A total of 100 tilapias were divided into four groups in a 2 × 2 factorial design, exploring two stunning methods with and without clove essential oil. Behavioral responses, glucose, lactate, pH, water holding capacity, color parameters, lipid and protein oxidation, and oxidative stress were analyzed. The application of clove essential oil resulted in 100% numbing in swimming and stimulus response behaviors, and 96% in balance and eye vestibule reflex variables. Significant reductions in glucose (12.12 mg dL−1) for hypothermia group (p = 0.001) and lactate (3.36 mmol L−1) for cranial percussion (p = 0.004), 0.028 nmol lipid oxidation in hypothermia treatment (p = 0.009), and 0.134 nmol carbonyls/mg protein (p = 0.001) were observed. There was a reduction in luminosity (p = 0.010) and red intensity (p = 0.001) in the group of fish fillet that received cranial percussion, however, there was no difference in the group stunned by hypothermia. Clove essential oil demonstrates effectiveness in pre-slaughter stress mitigation, influencing the antioxidant system positively. Its usage in pre-slaughter protocols could contribute to improved fillet quality, presenting a promising alternative for enhancing tilapia welfare during slaughter.

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.

The shear force and textural properties (hardness, elasticity and chewiness) of Ningxia Tan lamb meat stored at −80 ℃ (control), −2, −18 or 4 ℃ for 7 days were determined by cysteine oxidative modification proteomics. Meanwhile, the cysteine oxidation sites were identified, and the Pearson’s correlation was used to analyze the correlation between the oxidation intensity of significantly differential oxidation sites (SDOS) and the quality indicators of refrigerated Tan lamb meat. The results showed that compared with the control group, the shear force and texture characteristics of lamb meat in the experimental groups were significantly reduced (P < 0.05), and 25 SDOS proteins (including 10 structural proteins, 8 metabolic enzymes, 2 degradative enzymes and 5 other proteins) were significantly correlated with at least one quality indicator (P < 0.05), which could be used as potential biomarkers to evaluate changes in the tenderness and texture of lamb meat during storage.

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This study aimed to examine the potential antioxidant properties of pea peel powder (PPP) in minimizing lipid and protein oxidation, microbial count, and changes in overall quality of buffalo meat patties during refrigerated storage at a temperature of 4 ± 1 ℃. The analysis conducted for PPP revealed favorable phenolic and flavonoid content along with antioxidant activity. Additionally, PPP exhibited promising physicochemical features, including dietary fiber, good water holding and oil holding capacity. Patties were developed after incorporating 2, 4, 6, and 8% PPP (PPP1, PPP2, PPP3 and PPP4) respectively. The inclusion of PPP in the patties, particularly in the sample containing 8% PPP, yielded a significant elevation (P < 0.05) in dietary fiber content from 0.56 to 5.86%, accompanied by improved stability of lipids and proteins against oxidation. The incorporation of PPP at a level of 6% (PPP3) resulted in increased sensory ratings and an overall improvement in the quality of the patties. The inclusion of 8% PPP in the samples demonstrated a reduction in the total plate count of the samples from 6.96 to 5.06 log CFU/g on the 21st day of the study. Scanning electron microscopy images showed that compared to the control patties, the PPP-treated patties had less surface roughness and uneven distribution. Therefore, the incorporation of PPP has been demonstrated to be a successful approach for enhancing the patties' storage stability and dietary fiber, which may have potential health benefits. [ABSTRACT FROM AUTHOR]

Copyright of Shipin Kexue/ Food Science is the property of Food Science Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: Minimizing food oxidation remains a challenge in several environments. The addition of rosemary extract (150 mg kg−1) and lyophilized parsley (7.1 g kg−1) at equivalent antioxidant activity (5550 μg Trolox equivalents kg−1) to meat patties was assessed in terms of their effect during microwave cooking and after being subjected to an in vitro digestion process. RESULTS: Regardless of the use of antioxidants, cooking caused a decrease of the fat content as compared to raw samples, without noticing statistical differences in the fatty acid distribution between raw and cooked samples [44%, 47% and 6.8%, of saturated fatty acid (SFA), monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA), respectively]. However, the bioaccessible lipid fraction obtained after digestion was less saturated (around 34% SFA) and more unsaturated (35% MUFA +30% PUFA). Cooking caused, in all types of samples, an increased lipid [thiobarbituric acid reactive substances (TBARS)] and protein (carbonyls) oxidation values. The increase of TBARS during in vitro digestion was around 7 mg malondialdehyde (MDA) kg−1 for control and samples with parsley and 4.8 mg MDA kg−1 with rosemary. The addition of parsley, and particularly of rosemary, significantly increased the antioxidant activity (DPPH) of cooked and digested microwaved meat patties. CONCLUSION: Whereas rosemary was effective in minimizing protein oxidation during cooking and digestion as compared to control samples, parsley could only limit it during digestion. Lipid oxidation was only limited by rosemary during in vitro digestion. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Proteins are essential molecules that play crucial roles in maintaining cellular homeostasis and carrying out biological functions such as catalyzing biochemical reactions, structural proteins, immune response, etc. However, proteins also are highly susceptible to damage by reactive oxygen species (ROS) and reactive nitrogen species (RNS). In this review, we summarize the role of protein oxidation in normal aging and Alzheimer's disease (AD). The major emphasis of this review article is on the carbonylation and nitration of proteins in AD and mild cognitive impairment (MCI). The oxidatively modified proteins showed a strong correlation with the reported changes in brain structure, carbohydrate metabolism, synaptic transmission, cellular energetics, etc., of both MCI and AD brains compared to the controls. Some proteins were found to be common targets of oxidation and were observed during the early stages of AD, suggesting that those changes might be critical in the onset of symptoms and/or formation of the pathological hallmarks of AD. Further studies are required to fully elucidate the role of protein oxidation and nitration in the progression and pathogenesis of AD. [ABSTRACT FROM AUTHOR]

Amphioctopus neglectus is a species of octopus that is favored by consumers due to its rich nutrient profile. To investigate the influence of different thawing methods on the quality of octopus meat, we employed four distinct thawing methods: air thawing (AT), hydrostatic thawing (HT), flowing water thawing (FWT), and microwave thawing (MT). We then explored the differences in texture, color, water retention, pH, total volatile basic nitrogen (TVB–N), total sulfhydryl content, Ca2+–ATPase activity, and myofibrillar protein, among other quality indicators in response to these methods, and used a low-field nuclear magnetic resonance analyzer to assess the water migration that occurred during the thawing process. The results revealed that AT had the longest thawing time, leading to oxidation-induced protein denaturation, myofibrillar protein damage, and a significant decrease in water retention. Additionally, when this method was utilized, the content of TVB–N was significantly higher than in the other three groups. HT, to a certain extent, isolated the oxygen in the meat and thus alleviated protein oxidation, allowing higher levels of Ca2+–ATPase activity, sulfhydryl content, and springiness to be maintained. However, HT had a longer duration: 2.95 times that of FWT, resulting in a 9.84% higher cooking loss and a 28.21% higher TVB–N content compared to FWT. MT had the shortest thawing time, yielding the lowest content of TVB–N. However, uneven heating and in some cases overcooking occurred, severely damaging the protein structure, with a concurrent increase in thawing loss, W value, hardness, and shear force. Meanwhile, FWT improved the L*, W* and b* values of octopus meat, enhancing its color and water retention. The myofibrillar protein (MP) concentration was also the highest after FWT, with clearer subunit bands in SDS-PAGE electrophoresis, indicating that less degradation occurred and allowing greater springiness, increased Ca2+–ATPase activity, and a higher sulfhydryl content to be maintained. This suggests that FWT has an inhibitory effect on oxidation, alleviating protein oxidation degradation and preserving the quality of the meat. In conclusion, FWT outperformed the other three thawing methods, effectively minimizing adverse changes during thawing and successfully maintaining the quality of octopus meat. [ABSTRACT FROM AUTHOR]

Introduction: Cornelian cherry (Cornus mas L.) fruits are rich in vitamin C, phenolics and other compounds shaping their high antioxidant profile. Natural-based antioxidants may inhibit degradation of pivotal biological macromolecules such as DNA, proteins and molecular membranes. Objective: The study aimed to assess the cornelian cherry extract effect on the inhibition of protein oxidation, which could help limit generation of the advanced oxidation protein products (AOPPs), that are responsible for inflammatory states. Methods: The protective effect was evaluated in in vitro model, in which albumin solution was exposed to oxidation stress in the presence of different doses of C. mas extract. The results were supported by characteristics of the extract under their total phenolic, total flavonoid and vitamin C content. Also, the antioxidant potential was validated using ABTS test (TEAC). Results: Observed was moderate inhibitory effect of the extract and antiradical activity against ABTS. However, both studied effects rather result from other bioactive compounds than the flavonoids. Conclusion: Cornelian cherry fruits has moderate potential to inhibit protein oxidation. However, the observed antioxidant effect rather depends on other compounds than the flavonoids and vitamin C. Nonetheless, the collected results could be helpful in future designing and development of plant-based agents inhibiting the formation of AOPPs. [ABSTRACT FROM AUTHOR]

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In recent years, natural preservatives have attracted more and more attention in food processing since they can enhance food shelf-life and safety. In this study, the polyphenol extract was obtained from mangosteen peels using enzyme-microwave assisted method, characterized for its antioxidant and antimicrobial activities and subsequently used as a natural additive in fish ball preservation. Results revealed that the mangosteen peel polyphenol powder (MPP) had a high phenolic content of 154 mg gallic acid equivalent/g dry matter, which led to high 2,2-diphenyl-1-picrylhydrazyl free radical scavenging capacity of 95 mg Trolox equivalent/g dry matter. MPP also exhibited effective antimicrobial activity against E. coli and S. aureus, expressed by its large inhibitory zones (11.3 and 12.1 mm, respectively) and small ratios (less than 4) of minimum bactericidal concentration over minimum inhibitory concentration against tested bacteria. The MPP supplementation at the levels of 38 mg/100 g and 53 mg/100 g into fish balls remarkably improved their gel strength, reduced lipid oxidation, limited protein oxidation and structural degradation as compared to those of the control without any addition or with synthetic preservatives. Especially, the addition of 53 mg MPP/100 g could sufficiently retard the microorganism growth. The synergistic effects of MPP in both antioxidant and antimicrobial activities hence could extend the shelf-life of fish balls, more than 40 %, as compared to butylated hydroxytoluene (synthetic antioxidant) or sodium benzoate (synthetic antimicrobial) with their single effects. These findings imply that MPP could be potentially used as a natural additive in preservation of fish and meat products.

This study aimed to investigate the impact of different pickling methods on the water retention and protein structure of salted goose raw material. Five pickling methods, namely conventional curing, vacuum tumbling curing, ultrasound curing, ultrasound combined with tumbling curing, and salt and tumbling curing, were employed, with a curing duration of 2 hours. The cured goose meat samples were analyzed for cooking loss, centrifugal loss, microstructure, as well as the carbonyl content, surface hydrophobicity, total sulfhydryl content, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of the myofibrillar proteins. The results indicated that the ultrasound combined with tumbling curing method exhibited superior water-holding capacity, resulting in significant enhancement of the tenderness of goose meat. Additionally, this curing method caused the most notable damage to the microstructure of muscle fibers. The myofibrillar proteins in the ultrasound combined with tumbling cured goose meat exhibited lower surface hydrophobicity (5.17 μg) and carbonyl content (0.92 nmol/mg) compared to the vacuum tumbling, salt and tumbling, and ultrasound curing groups. Conversely, the total sulfhydryl content was highest (87.9 nmol/mg), indicating lower protein oxidation levels. SDS-PAGE analysis revealed prominent diffusion of protein bands at the 43 kDa position and denser bands between 26 and 43 kDa for the ultrasound combined with tumbling cured samples, indicating protein degradation. In conclusion, ultrasound combined with tumbling curing represents the optimum curing method.

The digestibility of myofibrillar proteins (MP) extracted from yak meat cooked to different internal temperatures of (40, 50, 60, 70 and 80 ℃) was determined during in vitro gastrointestinal digestion, and total carbonyl content, total sulfhydryl content and Schiff base content before and after digestion were measured. Ultraviolet (UV) absorption spectroscopy, endogenous fluorescence spectroscopy and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) were used to investigate the oxidation and digestion patterns of yak meat proteins during gastrointestinal digestion. The results showed that total protease hydrolysis of MP from yak meat cooked to 60 ℃ was the highest after simulated gastric and intestinal digestion (88.64%). The rates of pepsin hydrolysis and total protease hydrolysis of MP from yak meat cooked to 80 ℃ decreased by 34.10% and 22.47%, respectively, and the rate of trypsin hydrolysis increased by 75.34% compared with MP from raw yak meat. The total carbonyl content after simulated gastric and intestinal digestion increased by 81.42% and 77.40%, respectively, and the total sulfhydryl content decreased by 30.02% and 36.43%, respectively, compared with raw MP. With an increase in cooking temperature, the Schiff base content gradually increased, the UV absorbance was significantly enhanced, and the endogenous fluorescence intensity was significantly reduced. The SDS-PAGE patterns showed that the protein bands were severely degraded and even disappeared after digestion. It was found that the digestibility of MP from yak meat cooked to 60 ℃ was the highest. The degree of protein oxidation in yak meat cooked to 80 ℃ was the strongest and increased during gastrointestinal digestion.

BACKGROUND: The uses of egg white powder (EWP) are restricted because of its odor. It is necessary to find a method to improve its flavor. In this paper, three different antioxidants -- green tea extract (GTE), sodium ascorbate (SA), and glutathione (GSH) -- were selected to modify the flavor. The physicochemical and structural properties of EWP were investigated to study the mechanism of the formation and release of volatile compounds. RESULTS: Antioxidants can modify the overall flavor of EWP significantly, inhibiting the generation or release of nonanal, 3-methylbutanal, heptanal, decanal, geranyl acetone, and 2-pemtylfuran. A SA-EWP combination showed the lowest concentration of 'off' flavor compounds; GTE-EWP and GSH-EWP could reduce several 'off' flavor compounds but increased the formation of geranyl acetone and furans. The changes in the carbonyl content and the amino acid composition confirmed the inhibition of antioxidants with the oxidative degradation of proteins or characteristic amino acids. The results of fluorescence spectroscopy and Fourier transform infrared (FTIR) spectroscopy provided structural information regarding EWP, which showed the release of volatile compounds decreased due to structural changes. For example, the surface hydrophobicity increased and the protein aggregation state changed. CONCLUSIONS: Antioxidants reduce the 'off' flavor of EWP in two ways: they inhibit protein oxidation and Maillard reactions (they inhibit formation of 3-methylbutanal and 2-pemtylfuran) and they enhance the binding ability of heat-denatured proteins (reducing the release of nonanal, decanal, and similar compounds). [ABSTRACT FROM AUTHOR]

Copyright of Food & Fermentation Industries is the property of Food & Fermentation Industries and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The innate immune response represents the first-line of defense against invading pathogens. Reactive oxygen species (ROS) and reactive nitrogen species (RNS) have been implicated in various aspects of innate immune function, which involves respiratory bursts and inflammasome activation. These reactive species widely distributed within the cellular environment are short-lived intermediates that play a vital role in cellular signaling and proliferation and are likely to depend on their subcellular site of formation. NADPH oxidase complex of phagocytes is known to generate superoxide anion radical (O2 •-) that functions as a precursor for antimicrobial hydrogen peroxide (H2O2) production, and H2O2 is utilized by myeloperoxidase (MPO) to generate hypochlorous acid (HOCl) that mediates pathogen killing. H2O2 modulates the expression of redox-responsive transcriptional factors, namely NF-kB, NRF2, and HIF-1, thereby mediating redox-based epigenetic modification. Survival and function of immune cells are under redox control and depend on intracellular and extracellular levels of ROS/RNS. The current review focuses on redox factors involved in the activation of immune response and the role of ROS in oxidative modification of proteins in macrophage polarization and neutrophil function. [ABSTRACT FROM AUTHOR]

Summary: Silver carp myofibrillar proteins (MP) with different moleculars states were constructed by the addition of NaCl and fracture degree of muscle fibres. Results showed that salt‐dissolved MP (P+) under unfrozen and oxidised state showed higher oxidation degree with higher carbonyl (3.42 nmol mg−1) and dityrosine contents (25.98 a.u.) (P < 0.05) compared with saltless‐polymeric MP (P) and salt‐induced swelling MP (F+) due to addition of salt and broken muscle fibres. After oxidative and freeze–thaw process, P+ group also exhibited more cross‐linking as evidenced by turbidity (0.73), solubility (64.96%) and SDS‐PAGE, but unordered aggregates in P group increased probably due to severe frozen denaturation. Moreover, F+ group of salt‐induced swelling MP from intact muscle fibres suffered less structural damages with higher fluorescence intensity (668.41 a.u.) and higher α‐helix contents (15.56%). Overall, Fish‐ Hua of salt‐dissolved MP had a higher oxidation level and NaCl contributed to improve freeze–thaw stability of MP during freeze–thaw process. [ABSTRACT FROM AUTHOR]

Summary: This study aimed to determine differences in protein and lipid oxidation between bacon with KCl and calcium ascorbate (alternative) and with NaCl (traditional) during a two‐month storage process. At the beginning of storage, the carbonyl content and thiobarbituric acid reactive substances (TBARS) in alternative salt bacon were higher than those in traditional bacon, while the sulphhydryl content, fluorescence intensity and the α‐helix structure of alternative salt bacon protein were lower than those of traditional bacon. As the duration of storage progressed from 0 to 60 days, the degree of oxidation of proteins and fats in both groups of bacon increased, and the degree of oxidation of alternative salt bacon was stronger than that of traditional bacon. The results indicated that alternative salts can promote physicochemical changes in bacon to some extent. The changes in the protein and lipid oxidation of the two kinds of bacon during storage may led to the production of key volatile flavour substances and taste substances, which require further investigation. [ABSTRACT FROM AUTHOR]

Summary: Aquatic products are delicious and rich in high‐quality proteins, and thus have high‐food value and are popular among consumers; however, deterioration of their quality can easily occur when being stored and processed. Proteins, the main components of the muscle tissue of aquatic products, are closely related to the quality of aquatic products, and protein oxidation has become a research hotspot for studying the regulatory mechanisms of aquatic product quality changes. Protein oxidation is one of the main causes of quality deterioration of aquatic products, mainly because of protein cross‐linking and protein degradation caused by oxidation. Related studies have also shown that the changes in the electrostatic charge of proteins owing to oxidation are associated with the muscle water‐holding capacity (WHC). This article introduces the induction mechanism of protein oxidation in aquatic products, focusing on its effects on the quality, such as colour, texture, WHC and summarises the current research progress of aquatic products quality control on this basis to provide theoretical reference for future research. [ABSTRACT FROM AUTHOR]

Summary: This research aimed to evaluate the influence of different high‐intensity ultrasound (HIU) levels (control: 0; low: 276.36; moderate: 422.67; and high: 747.79 W cm−2) and stored in aerobic conditions for 7 days at 4 ± 1 °C on instrumental colour, metmyoglobin reducing activity (MRA), oxidative stability and texture of Longissimus lumborum (LL) from Nellore (Bos indicus) cattle. HIU moderate level samples exhibited higher (P < 0.05) lipid and protein oxidation, whereas high level showed higher MRA than control, low and moderate level counterparts. An increase (P < 0.05) of hue angle, MRA, lipid, and protein oxidation during refrigerated storage. Overall, the HIU levels did not influence pH, colour, texture, lipid, and protein oxidation, whereas HIU high level (HIU‐HL) improved the MRA contributing to beef colour stability. [ABSTRACT FROM AUTHOR]

This study focuses on the behavior of volatile organic compounds in beef after irradiation with 1 MeV accelerated electrons with doses ranging from 0.25 kGy to 5 kGy to find reliable dose-dependent markers that could be used for establishing an effective dose range for beef irradiation. GC/MS analysis revealed that immediately after irradiation, the chemical yield and accumulation rate of lipid oxidation-derived aldehydes was higher than that of protein oxidation-derived aldehydes. The nonlinear dose-dependent relationship of the concentration of volatile organic compounds was explained using a mathematical model based on the simultaneous occurrence of two competing processes: decomposition of volatile compounds due to direct and indirect action of accelerated electrons, and accumulation of volatile compounds due to decomposition of other compounds and biomacromolecules. A four-day monitoring of the beef samples stored at 4 °C showed that lipid oxidation-derived aldehydes, protein oxidation-derived aldehydes and alkanes as well as alcohol ethanol as an indicator of bacterial activity were dose-dependent markers of biochemical processes occurring in the irradiated beef samples during storage: oxidative processes during direct and indirect action of irradiation, oxidation due to the action of reactive oxygen species, which are always present in the product during storage, and microbial–enzymatic processes. According to the mathematical model of the change in the concentrations of lipid oxidation-derived aldehydes over time in the beef samples irradiated with different doses, it was found that doses ranging from 0.25 kGy to 1 kGy proved to be most effective for beef irradiation with accelerated electrons, since this dose range decreases the bacterial content without considerable irreversible changes in chemical composition of chilled beef during storage. [ABSTRACT FROM AUTHOR]

Protein kinase D (PKD) enzymes play important roles in regulating myocardial contraction, hypertrophy, and remodeling. One of the proteins phosphorylated by PKD is titin, which is involved in myofilament function. In this study, we aimed to investigate the role of PKD in cardiomyocyte function under conditions of oxidative stress. To do this, we used mice with a cardiomyocyte-specific knock-out of Prkd1, which encodes PKD1 (Prkd1loxP/loxP; αMHC-Cre; PKD1 cKO), as well as wild type littermate controls (Prkd1loxP/loxP; WT). We isolated permeabilized cardiomyocytes from PKD1 cKO mice and found that they exhibited increased passive stiffness (Fpassive), which was associated with increased oxidation of titin, but showed no change in titin ubiquitination. Additionally, the PKD1 cKO mice showed increased myofilament calcium (Ca2+) sensitivity (pCa50) and reduced maximum Ca2+-activated tension. These changes were accompanied by increased oxidation and reduced phosphorylation of the small myofilament protein cardiac myosin binding protein C (cMyBPC), as well as altered phosphorylation levels at different phosphosites in troponin I (TnI). The increased Fpassive and pCa50, and the reduced maximum Ca2+-activated tension were reversed when we treated the isolated permeabilized cardiomyocytes with reduced glutathione (GSH). This indicated that myofilament protein oxidation contributes to cardiomyocyte dysfunction. Furthermore, the PKD1 cKO mice exhibited increased oxidative stress and increased expression of pro-inflammatory markers interleukin (IL)-6, IL-18, and tumor necrosis factor alpha (TNF-α). Both oxidative stress and inflammation contributed to an increase in microtubule-associated protein 1 light chain 3 (LC3)-II levels and heat shock response by inhibiting the mammalian target of rapamycin (mTOR) in the PKD1 cKO mouse myocytes. These findings revealed a previously unknown role for PKD1 in regulating diastolic passive properties, myofilament Ca2+ sensitivity, and maximum Ca2+-activated tension under conditions of oxidative stress. Finally, we emphasized the importance of PKD1 in maintaining the balance of oxidative stress and inflammation in the context of autophagy, as well as cardiomyocyte function. [ABSTRACT FROM AUTHOR]

In addition to microbial spoilage and lipid peroxidation, protein oxidation is increasingly recognized as a major cause for quality deterioration of muscle-based foods. Although protein oxidation in muscle-based foods has attracted tremendous interest in the past decade, specific oxidative pathways and underlying mechanisms of protein oxidation in aquatic products remain largely unexplored. The present review covers the aspects of the origin and site-specific nature of protein oxidation, progress on the characterization of protein oxidation, oxidized proteins in aquatic products, and impact of protein oxidation on protein functionalities. Compared to meat protein oxidation, aquatic proteins demonstrate a less extent of oxidation on aromatic amino acids and are more susceptible to be indirectly oxidized by lipid peroxidation products. Different from traditional measurement of protein carbonyls and thiols, proteomics-based strategy better characterizes the targeted oxidation sites within proteins. The future trends using more robust and accurate targeted proteomics, such as parallel reaction monitoring strategy, to characterize protein oxidation in aquatic products are also given. [ABSTRACT FROM AUTHOR]

To investigate the effects of different thawing media such as plasma activated water (PAW), slightly acidic electrolytic water (SAEW), and 3% NaCl solution on the quality of jumbo squid, the frozen samples were thawed in the three abovementioned media at 4 °C, The effects of different thawing media on water retention, protein oxidation and structure of jumbo squid were analyzed, Results showed that PAW as thawing medium significantly improved the water- holding capacity of sample (P<0.01), and the cooking loss rate was 28.67%, which was significantly lower than that of the other three groups, Compared with other treatment groups, samples treated with PAW had the lowest carbonyl and dityrosine content and the highest sulfhydryl content, indicating a good inhibition of protein oxidation. The results of turbidity, endogenous fluorescence and UV spectra analysis showed that the PAW treatment group could reduce the degree of protein denaturation and maintain structural stability. Taken together, the PAW treatment had the best effect on water retention and autoxidation of jumbo squid. [ABSTRACT FROM AUTHOR]