Constraints on the superconducting order parameter in Sr2RuO4 from oxygen-17 nuclear magnetic resonance.

Phases of matter are usually identified through spontaneous symmetry breaking, especially regarding unconventional superconductivity and the interactions from which it originates. In that context, the superconducting state of the quasi-two-dimensional and strongly correlated perovskite Sr2RuO4 is considered to be the only solid-state analogue to the superfluid 3He-A phase1,2, with an odd-parity order parameter that is unidirectional in spin space for all electron momenta and breaks time-reversal symmetry. This characterization was recently called into question by a search for an expected 'split' transition in a Sr2RuO4 crystal under in-plane uniaxial pressure, which failed to find any such evidence; instead, a dramatic rise and a peak in a single-transition temperature were observed3,4. Here we use nuclear magnetic resonance (NMR) spectroscopy of oxygen-17, which is directly sensitive to the order parameter via hyperfine coupling to the electronic spin degrees of freedom, to probe the nature of superconductivity in Sr2RuO4 and its evolution under strain. A reduction of the Knight shift is observed for all strain values and at temperatures below the critical temperature, consistent with a drop in spin polarization in the superconducting state. In unstrained samples, our results contradict a body of previous NMR work reporting no change in the Knight shift5 and the most prevalent theoretical interpretation of the order parameter as a chiral p-wave state. Sr2RuO4 is an extremely clean layered perovskite and its superconductivity emerges from a strongly correlated Fermi liquid, and our work imposes tight constraints on the order parameter symmetry of this archetypal system.

Experimental evidence of ß-relaxation and its structural origin in ZIF-62 glass.

Intrinsic relaxation processes determine the crucial properties of glass, yet their underlying mechanisms are far from well understood. The brand-new glass-forming metal-organic frameworks (MOFs) provide desirable opportunities for looking inside glass relaxation, especially the secondary ß-relaxation phenomenon and mechanism. For a representative zeolitic imidazolate framework-62 (ZIF-62) glass, reliable and fine powder mechanical spectroscopy was performed based on home-made mountings combined with a commercial dynamical mechanical analyzer. For the first time, ß-relaxation was observed in a MOF glass besides the primary α-relaxation. The pronounced ß-relaxation was well demonstrated by a number of characteristics including an excess wing and the full width at half maximum (W) of the α-relaxation peaks, which deviated from the time-temperature superposition. The stretched exponent ß of ZIF-62 glass is 0.71 in the supercooled region. The W of ZIF-62 glass is the maximum among all known glassy materials. The structural origin of α- and ß-relaxation can be attributed to an increase of density, as observed using nuclear magnetic resonance (NMR). A general linear and broad correlation of fragility and stretched exponent ß with W of the α-relaxation peaks was established. When compared with traditional glass-formers, the resulting principles indicate a shared origin for the stretched exponent ß, W, and ß-relaxation in the case of ZIF-62 glass. The presented findings offer an effective new method to explore the glass/liquid transition of MOF glasses, which helps to obtain a deeper insight into the hierarchical relaxation dynamics of the glass transition.

Recent advances in the application of microalgae and its derivatives for preservation, quality improvement, and shelf-life extension of seafood.

Seafood is a highly perishable food product due to microbiological, chemical, and enzymatic reactions, which are the principal causes of their rapid quality deterioration. Therefore, ever-increasing consumers' demand for high-quality seafood along with a negative perception of synthetic preservatives creates opportunities for natural preservatives such as microalgae extracts. They are potential alternatives to reduce microbial growth, increase oxidative stability, and protect the sensorial properties of seafood. Research has shown that the inclusion of microalgae extracts into the aquatic animal's diet could enhance their meat quality and increase production. This review focuses on the direct application of various microalgae extracts as seafood preservative, and their functional properties in seafood, such as antioxidant and antimicrobial activities. Besides, the potential nutritional application of microalgae extracts as an alternative in aqua-feed and their impact on seafood quality (indirect application) are also presented. The safety aspects and regulatory issues of products from microalgae are highlighted.

Recent advances on characterization of protein oxidation in aquatic products: A comprehensive review.

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.

Spoilage-related microbiota in fish and crustaceans during storage: Research progress and future trends.

Fish and crustaceans are highly perishable due to microbial growth and metabolism. Recent studies found that the spoilage process of fish and crustaceans is highly related to their microbiota composition. Microbiota of fish and crustaceans changes dramatically during storage and can be influenced by many factors (e.g., aquaculture environment, handling process, storage temperature, and various quality control techniques). Among them, many quality control techniques have exhibited efficient effects on inhibiting spoilage bacteria, regulating microbiota composition, and retarding quality deterioration. In this article, we elucidate the relationship between microbiota composition and fish/crustacean spoilage, demonstrate influencing factors of fish/crustaceans microbiota, and review various quality control techniques (especially plant-derived preservatives) including their preservative effects on microbiota and quality of fish and crustaceans. Besides, present and future trends of various detective methods used in microbiota analysis are also compared in this review, so as to provide guides for future microbiota studies. To conclude, novel preservation techniques (especially plant-derived preservatives) and hurdle technologies are expected to achieve comprehensive inhibitory effects on spoilage bacteria. Efficient delivery systems are promising in improving the compatibility of plant-derived preservatives with fish/crustaceans and enhancing their preservative effects. Besides, spoilage mechanisms of fishery products that involve complex metabolisms and microbial interactions need to be further elucidated, by using omics technologies like metagenomics, metatranscriptomics, and metabolomics.

Asian carp: A threat to American lakes, a feast on Chinese tables.

Asian carp, which are widely distributed in Asia and Europe, are nutritious and popular with consumers. In China, Asian carp is a tasty dish and has been consumed for thousands of years. However, they are considered aggressive invasive species that threaten rivers, lakes, and indigenous species in the United States. Asian carp have proliferated greatly in the water basin of the Mississippi River and its tributaries, and they have caused severe ecological problems over the past 20 years. In recent years, several state governments along the Mississippi River have implemented assistance programs to eliminate invasive Asian carp, but these did not alleviate the threat. We conducted a survey to understand consumers' attitudes toward Asian carp in the United States, and related reports were reviewed to explore the possibility of Asian carp as food fish on American tables. Emphasis is placed on the farming history, functional characteristics, consumption preferences, and successful utilization methods for Asian carp in China. In addition, suggestions and possible utilization methods were proposed to improve the negative impression of Asian carp in the United States. Further research is needed to take full advantage of this huge excellent source of food or health supplements. This review provides ideas and directions for the use of Asian carp in the United States. We believe that through effective cooperation between China and the United States, the negative aspects of Asian carp in the United States could be diminished, and a mutually beneficial situation could be achieved.

Purification and characterization of antioxidant peptides from yak (Bos grunniens) bone hydrolysates and evaluation of cellular antioxidant activity.

In this study, papain and alcalase were used to generate antioxidant peptides from yak bone protein. The antioxidant activities of hydrolysates in vitro were evaluated by 2,2'-azinobios-(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging activity, total reducing power, ferrous ion chelating ability and hydroxyl radical scavenging activity. The hydrolysates generated by alcalase possessed the best antioxidant activity among unhydrolyzed protein and samples treated by papain, but the antioxidant activity decreased after simulated gastrointestinal digestion in vitro. The products of simulated gastrointestinal digestion were separated by ultrafiltration and high performance liquid chromatography, and the amino acid sequences of peptides were identified by mass spectrometry. The digestion sites within peptides were predicted by a bioinformatics strategy, and ten peptides were selected for synthesis. Among 10 synthetic peptides, Gly-Phe-Hyp-Gly-Ala-Asp-Gly-Val-Ala, Gly-Gly-Pro-Gln-Gly-Pro-Arg and Gly-Ser-Gln-Gly-Ser-Gln-Gly-Pro-Ala possessed strong antioxidant activities, among which Gly-Phe-Hyp-Gly-Ala-Asp-Gly-Val-Ala had a significant cytoprotective effect in Caco-2 cells under oxidative stress induced by H2O2, which reduced the formation of reactive oxygen species and malondialdehyde, and improved the activity of antioxidant enzymes in cells. These results showed that yak bone peptides exhibited strong antioxidant activity and have a potential value as a new type of natural antioxidant.

Rectangular illumination method using LED arrays for machine vision.

Machine vision image quality is significantly affected by illumination. Uniform illumination of a rectangular target surface requires a function for evaluating the illumination system. In this study, based on an LED array light source illuminance model, such an evaluation function was established. Further, the influence of the light source's structure on illumination was analyzed using a single-factor analysis method to determine the boundary conditions, and it was then solved using a genetic algorithm to finalize the structural design. An experimental platform was built to measure the illuminance uniformity. The experimental results were consistent with the numerical results, verifying the effectiveness and feasibility of the proposed illumination method. Thus, this research provides a theoretical reference for the illumination of a rectangular target surface for vision-based detection.

Effects of phytic acid and lysozyme on microbial composition and quality of grass carp (Ctenopharyngodon idellus) fillets stored at 4 °C.

This study investigated the effect of phytic acid and lysozyme on the microbial composition and quality of grass carp (Ctenopharyngodon idellus) fillets stored at 4 °C. The control, 0.5 mg/mL lysozyme-treated fillets (T1), 0.5 mg/mL phytic acid-treated fillets (T2) and 0.25 mg/mL lysozyme + 0.25 mg/mL phytic acid-treated fillets (T3) were evaluated based on sensory assessment, biogenic amines, ATP-related compounds, total volatile basic nitrogen (TVB-N), and total viable counts (TVC). Changes in microbial composition were analyzed using high-throughput sequencing. Results showed that phytic acid and lysozyme treatment delayed the decrease in sensory scores, reduced the rate of degradation of IMP to Hx, inhibited the growth of microorganisms, and attenuated the increase in TVB-N and putrescine. Phytic acid exhibited better preservation effects than lysozyme and their combination was more effective than using either alone. High-throughput sequencing showed that Acinetobacter and Kocuria were the predominant bacteria in fresh grass carp, but Pseudomonas rose rapidly with storage time; Pseudomonas, Shewanella, and Aeromonas constituted the main spoilage bacteria of grass carp fillets. Lysozyme treatment significantly reduced the proportion of Shewanella and Acinetobacter, and phytic acid and the combination of phytic acid and lysozyme significantly reduced the proportion of Pseudomonas in spoiled grass carp fillets.

TMT-based proteomic analysis of the fish-borne spoiler Pseudomonas psychrophila subjected to chitosan oligosaccharides in fish juice system.

P. psychrophila is implicated in fish spoilage especially under cold storage. In the present study, tandem mass tag (TMT) quantitative proteomic analysis was performed to clarify the molecular mechanism for the inhibitory effect of chitosan oligosaccharides (COS) against P. psychrophila in fish juice system. The MIC and MBC of the COS against P. psychrophila were 6 and 8 mg/mL, respectively. Compared with the untreated control, a total of 370 proteins (163 up-regulated and 207 down-regulated) were identified as differentially expressed proteins (DEPs, >1.5-fold or < 0.67-fold, P < 0.05) in P. psychrophila when exposed to 6 mg/mL COS. Bioinformatics analysis indicated that the DEPs were mainly involved in the cell wall/membrane, cell motility, and electron-transport chain; DNA replication, RNA transcription and translation, posttranslational modifications of proteins; TCA cycle, and the transport and metabolism of amino acid, carbohydrate, and ion. The scanning electron microscope (SEM) and fourier-transform infrared spectroscopy (FT-IR) analysis further validated that cell structure especially the cell wall/membrane was damaged after COS treatment. The results in this study presented an important step toward understanding the response of P. psychrophila cells to COS at the proteome level.

Assessment of bacterial contributions to the biochemical changes of chill-stored blunt snout bream (Megalobrama amblycephala) fillets: Protein degradation and volatile organic compounds accumulation.

In this study, we evaluated the contributions of three bacteria (Pseudomonas versuta, Shewanella putrefaciens, and Aeromonas sobria) to the proteolysis, biogenic amines formation, volatile organic compounds accumulation, lipid oxidation, nucleotide catabolism, discoloration, and water migration of bream flesh during chilled storage. The results showed that P. versuta exhibited hydrolyzing activity against sarcoplasmic proteins, and all three strains could degrade myofibrillar proteins, specifically actin. The highest producer of putrescine was S. putrefaciens, which reached a maximum level 5.05 mg/kg after 14 days. Compared with the A. sobria group, hypoxanthine riboside degraded faster in samples inoculated with P. versuta or S. putrefaciens, A. sobria, P. versuta, and S. putrefaciens were responsible for the production of alcohol and aldehydes, whereas only S. putrefaciens produced thiophene and partial esters. Fish flesh inoculated with P. versuta, S. putrefaciens, and A. sobria presented slight green, yellow, and pink discoloration, respectively.

Effect of grape seed extract on quality and microbiota community of container-cultured snakehead (Channa argus) fillets during chilled storage.

Herein, the effects of grape seed extract (GSE) on the microflora and biochemical changes of container cultured snakehead (Channa argus) fillets during 11 days of chilled storage were investigated. The sensory analysis, the total number of viable colonies, the total amount of volatile basic nitrogen, and k-value analysis revealed that GSE retarded the deterioration of snakehead fillets. The degradation of inosine 5'-monophosphate and the accumulation of inosine and hypoxanthine in the GSE group were slower than these in the control group. Moreover, GSE treatment effectively decreased the accumulation of putrescine, cadaverine, and histamine. Illumina-MiSeq high throughput sequencing results showed that GSE inhibited the growth of Aeromonas on snakehead fillets. Based on the microbial enumeration, sensory analysis, and k-value, GSE prolonged the shelf life of fillets for 3 days, suggesting its potential for snakehead fillets preservation.

Competing magnetic orders in the superconducting state of heavy-fermion CeRhIn5.

Applied pressure drives the heavy-fermion antiferromagnet CeRhIn5 toward a quantum critical point that becomes hidden by a dome of unconventional superconductivity. Magnetic fields suppress this superconducting dome, unveiling the quantum phase transition of local character. Here, we show that [Formula: see text] magnetic substitution at the Ce site in CeRhIn5, either by Nd or Gd, induces a zero-field magnetic instability inside the superconducting state. This magnetic state not only should have a different ordering vector than the high-field local-moment magnetic state, but it also competes with the latter, suggesting that a spin-density-wave phase is stabilized in zero field by Nd and Gd impurities, similarly to the case of Ce0.95Nd0.05CoIn5 Supported by model calculations, we attribute this spin-density wave instability to a magnetic-impurity-driven condensation of the spin excitons that form inside the unconventional superconducting state.

Effects of pomegranate peel extract on quality and microbiota composition of bighead carp (Aristichthys nobilis) fillets during chilled storage.

This study aimed to investigate effects of aqueous pomegranate peel extract (APPE) and ethanolic pomegranate peel extract (EPPE) on microbiota and changes in quality of bighead carp (Aristichthys nobilis) fillets stored at 4 °C. The results showed that pomegranate peel extract (PPE, which includes both APPE and EPPE) retarded the deterioration of sensory quality and flesh color, inhibited the growth of spoilage bacteria, and attenuated the production of biogenic amines, total volatile basic nitrogen (TVB-N), and the degradation of ATP-related compounds. Moreover, EPPE performed better in color attributes and biogenic amines, but APPE was more effective in retarding the increase of TVB-N and K-value. High-throughput sequencing results showed that microbial composition of all samples became less diverse as storage time increased. For the control group, Acinetobacter was predominant in the middle-period of storage, while Pseudomonas, Aeromonas, and Shewanella became predominant at the end of storage. Additionally, PPE decreased the relative abundance of Acinetobacter in the middle-period of storage, and thus changed the microbial composition. Based on our assessments of quality and microbial analysis, PPE prolonged the shelf-life of bighead carp fillets for about 2 days, and it has the potential to become a promising preservative in aquatic products.

Biochemical changes induced by dominant bacteria in chill-stored silver carp (Hypophthalmichthys molitrix) and GC-IMS identification of volatile organic compounds.

To evaluate the spoilage potential of dominant bacteria (Aeromonas allosaccharophila, Pseudomonas psychrophila, and Shewanella putrefaciens) isolated from spoiled silver carp (Hypophthalmichthys molitrix) fillets, biochemical changes including protein degradation, trichloroacetic acid (TCA)-soluble peptides, total volatile basic nitrogen (TVB-N), biogenic amines, nucleotide catabolism, and volatile organic compounds were examined in single-species inoculated silver carp flesh for 14 days at 4 °C. P. psychrophila exhibited the strongest proteolytic activity, which resulted in the highest concentrations of TCA-soluble peptides and TVB-N. S. putrefaciens was responsible for the production of putrescine and cadaverine and led to the fastest degradation of hypoxanthine riboside (HxR). At the end of storage, P. psychrophila was the main producer of ketones, especially the C7-C9 ketones, while sulfur compounds were released primarily by S. putrefaciens. Moreover, 1-propanol, butanone, 2-hexanone, methyl isobutyl ketone, dimethyl sulfide, and dimethyl disulfide increased gradually with storage time, suggesting their potential as spoilage markers for freshness/spoilage monitoring. P. psychrophila possessed the strongest spoilage potential in the fish matrix, followed by S. putrefaciens, whereas A. allosaccharophila showed a very low spoilage potential. In conclusion, P. psychrophila and S. putrefaciens were identified as the specific spoilage organisms (SSOs) of silver carp, suggesting that preservation researchers should focus on these two spoilage contributors in future studies. This research contributes to a deeper understanding of silver carp spoilage and to the development of methods and tools to improve fish quality management.

Effect of ε-polylysine and ice storage on microbiota composition and quality of Pacific white shrimp (Litopenaeus vannamei) stored at 0 °C.

This study evaluated the effects of ε-Polylysine and ice storage on microbiota composition and quality attributes of Pacific white shrimp stored at 0 °C. The sensorial shelf-life of control, 0.1% ε-Polylysine treated group, and ice stored group were 5, 8, and 7 days, respectively. Microbiota composition was explored by the Illumina-MiSeq high throughput sequencing targeting of 16S rRNA genes. At the time of sensory rejection, Pseudoalteromonas, followed by Candidatus Bacilloplama and Psychromonas, were the dominant microbiota in spoiled control samples on day 5. However, 0.1% ε-Polylysine inhibited the growth of Pseudoalteromonas and Psychromonas. Consequently, Candidatus Bacilloplama followed by Aliivibrio became the dominant microbiota in the ε-Polylysine treated group on day 8. Meanwhile, Aliivibrio, followed by Moritella and Pseudoalteromonas were the dominant microbiota in ice stored samples on day 7. Furthermore, due to the modulating effect of ε-Polylysine and ice storage on microbiota, chemical changes of the treated groups were slower, which was reflected as lower concentrations of total volatile basic nitrogen, putrescine, cadaverine, and hypoxanthine, and higher contents of inosine 5'-monophosphate and hypoxanthine riboside at the end of storage. In conclusion, ε-Polylysine and ice storage altered the microbiota composition and delayed quality deterioration of Pacific white shrimp.

Effects of collagen peptides intake on skin ageing and platelet release in chronologically aged mice revealed by cytokine array analysis.

Action mechanisms underlying various biological activities of collagen peptides (CPs) remained to be elucidated. Cytokines may play an important role in mediating these health benefits of CPs. This study aimed to systemically examine the cytokines in skin and blood regulated by CPs intake. Thirteen-month-old female Kunming mice were administered with CPs for 2 months (0 or 400 mg/kg bodyweight/day). The cytokines in skin and plasma were analysed using a 53-cytokine array and corresponding ELISA kits. In skin, CPs intake significantly down-regulated placenta growth factor (PIGF-2), insulin-like growth factor (IGF)-binding protein (IGFBP) -2 and IGFBP-3, and up-regulated platelet factor 4 (PF4), serpin E1 and transforming growth factor (TGF)-ß1 . CPs treatment also increased the type I collagen mRNA and protein levels and improved the aged skin collagen fibres. In plasma, nine cytokines were significantly down-regulated by CPs intake compared to the model group: fibroblast growth factor (FGF)-2, heparin-binding (HB) epidermal growth factor (EGF)-like growth factor (HB-EGF), hepatocyte growth factor (HGF), platelet-derived growth factor (PDGF)-AB/BB, vascular endothelial growth factor (VEGF), chemokine (C-X-C motif) ligand 1 (KC), matrix metalloproteinase (MMP)-9, interleukin (IL)-1α and IL-10; 2 cytokines were significantly up-regulated, including TGF-ß1 and serpin F1. Furthermore, CPs intake significantly decreased the level of platelet release indicators in the plasma and washed platelets, including PF4, granule membrane protein (GMP)-140, ß-thromboglobulin and serotonin. These results provide a mechanism underlying anti-skin ageing by CPs intake and highlight potential application of CPs as a healthcare supplement to combat cancer and cardiovascular disease by inhibiting platelet release.

Tuning the Pairing Interaction in a d-Wave Superconductor by Paramagnons Injected through Interfaces.

Unconventional superconductivity and magnetism are intertwined on a microscopic level in a wide class of materials. A new approach to this most fundamental and hotly debated issue focuses on the role of interactions between superconducting electrons and bosonic fluctuations at the interface between adjacent layers in heterostructures. Here we fabricate hybrid superlattices consisting of alternating atomic layers of the heavy-fermion superconductor CeCoIn_{5} and antiferromagnetic (AFM) metal CeRhIn_{5}, in which the AFM order can be suppressed by applying pressure. We find that the superconducting and AFM states coexist in spatially separated layers, but their mutual coupling via the interface significantly modifies the superconducting properties. An analysis of upper critical fields reveals that, upon suppressing the AFM order by applied pressure, the force binding superconducting electron pairs acquires an extreme strong-coupling nature. This demonstrates that superconducting pairing can be tuned nontrivially by magnetic fluctuations (paramagnons) injected through the interface.

Changes in microbial communities and quality attributes of white muscle and dark muscle from common carp (Cyprinus carpio) during chilled and freeze-chilled storage.

This study investigated sensory scores, quality attributes and microbial communities in white muscle and dark muscle of common carp (Cyprinus carpio) during chilled (4 °C) and freeze-chilled (-20 °C for 4 weeks prior to 4 °C) storage. Compared to the samples at the end of storage, fresh samples and frozen-thawed samples on day 0 showed greater bacterial diversity and more differences in microbiota. Initially, Aeromonas was the prevalent genus in fresh white muscle and dark muscle. As time progressed, Aeromonas followed by Pseudomonas predominated in white muscle, while Aeromonas, Pseudomonas, and Lactococcus dominated in dark muscle. Paenibacillus was identified as the largest population in frozen-thawed samples of both muscle types, but Pseudomonas increased dramatically to become dominant in the two spoiled samples. Volatile organic compounds (VOCs) of carp muscle consisted mainly of aldehydes and alcohols, and the percentage of ketones in both muscle types increased considerably after storage. Moreover, dark muscle showed more kinds of VOCs, and a slower rate of quality deterioration than white muscle. Based on sensory assessment, the shelf-life of white muscle and dark muscle of common carp for chilled storage was 8 days and 10 days, respectively, as well as 8 days together for freeze-chilled storage.

Monitoring bacterial communities in ε-Polylysine-treated bighead carp (Aristichthys nobilis) fillets using culture-dependent and culture-independent techniques.

The present study investigated the effect of ε-Polylysine on bacterial communities, sensorial, and chemical properties [total volatile basic nitrogen (TVB-N), biogenic amines, and breakdown products of adenosine triphosphate] of bighead carp (Aristichthys nobilis) fillets stored at 4 ±â€¯1 °C. Bacterial communities were explored by the culture-dependent method and the high-throughput sequencing targeting on 16S rRNA genes. The results showed that the major genera in spoiled control samples were Aeromonas, Pseudomonas, Shewanella, and Acinetobacter. ε-Polylysine inhibited the growth of Pseudomonas, Shewanella, and Acinetobacter. Consequently, Aeromonas and Janthinobacterium were dominant in spoiled treated samples. The sensorial shelf-life of the control and treated groups were 8 days and 10 days, respectively. Furthermore, due to the inhibitory effect of ε-Polylysine on bacteria, chemical changes of the treated group were slower, reflecting as lower concentrations of TVB-N, putrescine, cadaverine, and hypoxanthine, and higher contents of inosine 5'-monophosphate and hypoxanthine riboside at the end of storage. In conclusion, ε-Polylysine altered the bacterial communities and delayed quality deterioration of bighead carp fillets during chilled storage.