Search

Actuotaphonomic experiments demonstrate how microbial mats prevent or delay destructive processes. The rate at which carcasses are covered is a key to their preservation. Because of the growth rate of microbial mats depends on environmental conditions, a set of experiments have been carried out emulating the Barremian environmental conditions, analysed for temperatures at 14°C and 26°C (cooler and warmer seasons respectively) and atmospheric pCO2 (1000 ppm). For this purpose, the microbial mats were grown in mesocosms within an environmental chamber. Variations in primary production were quantified by measuring changes in dissolved O2 concentration in the water. Zebrafish carcasses were laid on the mats, and their coverage rates were calculated from the daily surface area covered by the mat. The results showed that the fish was covered twice as fast at 26°C, in coincidence with the highest values for the gross primary production and community respiration of the microbial mats. Therefore, for these Barremian conditions, the early stages of carcasses preservation would take place most effectively during the warmer seasons as decomposing activity would release nutrients that would enhance, together with temperature, the growth of mats. [ABSTRACT FROM AUTHOR]

In this study, novel functional ZEO-complex gels were prepared using sodium alginate, inulin, grape seed extract (GSE), and Zanthoxylum bungeanum essential oil (ZEO) as the primary raw materials. The effect of the addition of inulin, GSE, and ZEO on water vapor permeability (WVP), tensile strength (TS), and elongation at break (EAB) of ZEO-complex polysaccharide gels was investigated. A comprehensive score (Y) for evaluating the characteristics of ZEO-complex polysaccharide gels was established by principal component analysis. MATLAB analysis and box-Behnken design describe each factor's four-dimensional and three-dimensional interactions. It was found that Y could reach the maximum value when the ZEO addition was at a moderate level (C = 2%). The optimum preparation process of ZEO-complex polysaccharide gels was as follows: the addition of inulin was at 0.84%, the addition of GSE was at 0.04%, and the addition of ZEO was at 2.0785%; in this way, the Y of ZEO-complex polysaccharide gels reached the maximum (0.82276). Optical scanning and X-ray diffraction tests confirmed that the prepared ZEO-complex gels have a smooth and continuous microstructure, good water insulation, and mechanical properties. The storage test results show that ZEO-complex polysaccharide gels could play a significant role in the storage and fresh-keeping of grass carp, and the physicochemical properties of complex polysaccharide gels were improved by adding ZEO. In addition, according to the correlation of fish index changes during storage, adding ZEO in complex polysaccharide gels was closely correlated with the changes in fish TBARS and TVB-N oxidation decay indices. In conclusion, the ZEO-complex polysaccharide gels prepared in this study had excellent water insulation, mechanical properties, and outstanding fresh-keeping effects on grass carp. [ABSTRACT FROM AUTHOR]

Summary: This study aimed to evaluate the effect of chitosan (CHI) combined electrolytic water (EW) cold sterilisation on muscle quality and myofibril proteins (MP) of large yellow croaker (Pseudosciaena crocea) during 12 days of refrigerated storage (4 °C). After the storage period, the sample of the EW + CHI group had the highest rate of hardness (36.68%), springiness (16.11%) among the control group without any treatment (CON), CHI group and EW group and similar tendencies were found in chewiness and cohesiveness. The MP content in the CON group decreased sharply from 80.35 mg g−1 to 57.90 mg g−1, in contrast to the EW + CHI group, which decreased from 81.65 mg g−1 initially to 80.83 mg g−1. The conformation of MP α‐helix and β‐sheet was retained to protect the secondary structure, and the exposure of aromatic amino acid residues was constrained to defend the tertiary structure in EW + CHI treatment which effectively delayed the degradation of MP. Based on these outcomes, EW + CHI treatment could significantly maintain the MP of large yellow croakers and prevent corruption during refrigerated storage. [ABSTRACT FROM AUTHOR]

A number of shelf life-promoting strategies have been adopted for fish and fisheries products. The in vitro preservative effect of Ag-nanoparticles synthesized using Launaea taraxacifolia leaves on Atlantic cod fish (Gadus morhua) was investigated. The treated (TRD) fish samples were dipped in 25% silver nanoparticles (AgNPs) preparation for 30 minutes and analyzed at four hours intervals for 24 hours. Samples were cut into Head (H), Trunk (TR), and Tail (TL) parts and evaluated for total heterotrophic bacterial counts (THBC) and total yeast counts (TYC) all expressed in log CFU/g. Untreated (UTD) served as control. The concentrations of silver in both treated and untreated fish samples were determined. Data were analyzed using descriptive statistics and ANOVA at a0.05. The treated samples recorded lower THBC values than the untreated: head (6.18±0.27 vs 6.55±0.65); trunk (6.22±0.11 vs 6.61±0.41) and tail (6.40±0.34 vs 6.57±0.83). The treated samples had lower TYC values than the untreated: head (6.34±0.58 vs 7.44±0.38), trunk (6.59±0.66 vs 7.05±0.46) and tail (6.47±0.30 vs 6.81±0.95). Both the treated and the untreated samples were dominated by Enterococcus spp. (569 vs 957) and Micrococcus spp. (13 vs 18). Bacillus spp. (36) was isolated only in the untreated sample. The silver concentrations were highest in untreated and treated trunk samples respectively (1.12 and 2.13µg/g), followed by head samples (0.58 and 1.41µg/g) while the tail samples had the least (0.27 and 0.29 µg/g). The Ag-nanoparticles synthesized from Launaea taraxacifolia leaves exhibited both antibacterial and antifungal activities and could be useful in preserving fish and fishery products. [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.)

In this study, novel functional ZEO-complex gels were prepared using sodium alginate, inulin, grape seed extract (GSE), and Zanthoxylum bungeanum essential oil (ZEO) as the primary raw materials. The effect of the addition of inulin, GSE, and ZEO on water vapor permeability (WVP), tensile strength (TS), and elongation at break (EAB) of ZEO-complex polysaccharide gels was investigated. A comprehensive score (Y) for evaluating the characteristics of ZEO-complex polysaccharide gels was established by principal component analysis. MATLAB analysis and box-Behnken design describe each factor’s four-dimensional and three-dimensional interactions. It was found that Y could reach the maximum value when the ZEO addition was at a moderate level (C = 2%). The optimum preparation process of ZEO-complex polysaccharide gels was as follows: the addition of inulin was at 0.84%, the addition of GSE was at 0.04%, and the addition of ZEO was at 2.0785%; in this way, the Y of ZEO-complex polysaccharide gels reached the maximum (0.82276). Optical scanning and X-ray diffraction tests confirmed that the prepared ZEO-complex gels have a smooth and continuous microstructure, good water insulation, and mechanical properties. The storage test results show that ZEO-complex polysaccharide gels could play a significant role in the storage and fresh-keeping of grass carp, and the physicochemical properties of complex polysaccharide gels were improved by adding ZEO. In addition, according to the correlation of fish index changes during storage, adding ZEO in complex polysaccharide gels was closely correlated with the changes in fish TBARS and TVB-N oxidation decay indices. In conclusion, the ZEO-complex polysaccharide gels prepared in this study had excellent water insulation, mechanical properties, and outstanding fresh-keeping effects on grass carp.

Fish, being a significant biological indicator in water, serves as a valuable food source once harvested. However, the high protein content in fish makes it an ideal medium for microorganisms, which can lead to spoilage. In areas without access to freezers or ice, preserving fish becomes a challenge. The objective of this study is to investigate the efficacy of Psidium guajava (guava) leaves as a natural preservation method for Pangasius pangasius fish. Key parameters, including gills, eye, texture, odor, and mucilage, were used to evaluate fish quality. Leaf methanolic extract was applied at doses of 0%, 20%, 40%, 60%, and 80%. Data were collected between 1 and 3 days after storage. Results showed that fish quality declined and began to deteriorate after 2 days of storage, particularly in the control treatment (0% extract). However, the fish samples treated with doses of 60% and 80% experienced relatively good quality over the course of 2 days. Although some spoilage occurred in these samples, they remained suitable for consumption. In contrast, fish samples treated with other doses exhibited complete spoilage and were no longer consumable. In conclusion, guava leaf extracts offer a promising alternative for fish preservation. [ABSTRACT FROM AUTHOR]

Fresh fish is a perishable food in which chemical (namely oxidation) and microbiological degradation result in undesirable odor. Non-processed fish (i.e., raw fish) is increasingly commercialized in packaging systems which are convenient for its retailing and/or which can promote an extension of its shelf-life. Compared to fish sent to its retail unpackaged, fish packaging results in a modification of the gaseous composition of the atmosphere surrounding it. These modifications of atmosphere composition may affect both chemical and microbiological degradation pathways of fish constituents and thereby the volatile organic compounds produced. In addition to monitoring Total Volatile Basic Nitrogen (TVB-N), which is a common indicator to estimate non-processed fish freshness, analytical techniques such as gas chromatography coupled to mass spectrometry or techniques referred to as "electronic nose" allow either the identification of the entire set of these volatile compounds (the volatilome) and/or to selectively monitor some of them, respectively. Interestingly, monitoring these volatile organic compounds along fish storage might allow the identification of early-stage markers of fish alteration. In this context, to provide relevant information for the identification of volatile markers of non-processed packaged fish quality evolution during its storage, the following items have been successively reviewed: (1) inner atmosphere gaseous composition and evolution as a function of fish packaging systems; (2) fish constituents degradation pathways and analytical methods to monitor fish degradation with a focus on volatilome analysis; and (3) the effect of different factors affecting fish preservation (temperature, inner atmosphere composition, application of hurdle technology) on volatilome composition. [ABSTRACT FROM AUTHOR]

The origin of fish smoking dates back to antiquity. It is thought that the process was started by hanging the fish product over a fire which was used to reduce the moisture content of the product. Further advancement was made traditionally by the erection of mud, bricks or corrugated iron angle bar. The gas smoking kiln has been developed using locally available materials in the study area towards improving the existing fish smoking kiln techniques. The objective of this work is to improve the quality of smoked fish in Kainji Lake Basin in Nigeria at minimum production cost. The preliminary test performance of the kiln has been conducted using Clarias gariepinus. The result obtained shows that the kiln is less labour intensive and can handle different sizes of fish faster with better appearance of the end product than the conventional smoking methods.

Copyright of Food Research & Development is the property of Food Research & Development 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.)

Archaeological evidence for the preparation of preserved fish is common. Preserving fish allowed stockpiling of temporary abundance of food created by good catches and seasonal plenty. In traditional societies, the majority of fish caught are preserved for later use rather than consumed fresh. Ethnographic information from southeast Arabia, and the wider region, for the storage of fish provides interesting details of the process. Archaeological evidence for fish storage is not usually the stored product itself, but distinctive species and element composition of preparation waste or post‐consumption refuse. Archaeologists rarely excavate a complete cache of preserved fish. This study presents data from a fish storage pit, capped with a mud seal, excavated at the Late Islamic site of Freiha (al‐Furayḥa) in Qatar. The contents of the pit were intact providing an opportunity to examine the practice of storing dried fish from the product itself and compare this evidence to ethnographic accounts. [ABSTRACT FROM AUTHOR]

Ice is commonly used to preserve fish, but ice crushers are not always available in rural and remote areas of Bangladesh. A low-cost hand-operated ice crusher machine was developed in the Department of Farm Power and Machinery at Bangladesh Agricultural University. The machine yielded a throughput capacity of 21.6 kg min-1 with an average loss of 13.1%. The average time to crush a 10.6 kg ice block was 21.6 seconds. The total deformation, strain energy, maximum shear stress, and structural error were estimated as 0.0046 mm, 0.0031 MJ, 28 MPa, and 0.0025 MJ, respectively, for a single spike of the crusher. The average revolution per minute of the crushing cylinder was 493.6, with a maximum value of 634.7, and the maximum vibration frequency was 10.7 Hz. The maximum noise level during crushing operation was 92.9 dB, which was within the acceptable range. The machine's ergonomic assessment after operation yielded a satisfactory result. On average, the operators' blood pressure (systolic and diastolic), pulse rate, and respiration rate were 138.4 and 74.2 mm (Hg), 105.4 per minute, and 20 per minute, respectively. The results of the performance evaluation indicate that the device appears to be a suitable input for marginal fish farmers with inadequate access to electricity. [Fundam Appl Agric 2022; 7(1.000): 60-74]

In this figure, anthocyanins and CQDs powders prepared from barley bran were applied to the film matrix. The anthocyanin film was used as the outer color developing film, and then the CQDs electrospinning blend was spun onto the outer film to obtain a bilayer film. Subsequently, the structure and properties of the bilayer film were measured. [Display omitted] • The bilayer film loaded with anthocyanins and CQDs was prepared successfully. • Excellent antioxidant and photodynamic antibacterial properties were discovered in the PSA @ PHC bilayer film. • The PSA@PHC30 film extended the shelf life of fish by 2 d for freshness monitoring. Anthocyanins and carbon quantum dots (CQDs) were produced from highland barley bran to lower the waste of the cereal. This study successfully prepared a polyvinyl alcohol/soy protein isolate/anthocyanin@ polyvinyl alcohol/chitosan quaternary ammonium salt/CQDs nanofiber smart double-layer film (PSA@PHC). We explored the functions of anthocyanin film (PSA) and CQDs nanofiber film (PHC) as the inner and outer layers through structural characterization and property determination. The results showed that as the CQDs in nanofiber film rose, the diameter of the nanofibers expanded by 42.82 ± 9.37 nm, the free radical scavenging ability of DPPH and ABTS was 77.95 ± 2.53 % and 93.15 ± 0.70 %, respectively. When exposed to a xenon lamp, the bilayer film's CQDs generated reactive oxygen species, enhancing the inhibition of S. aureus and E. coli by 67.70 ± 0.54 % and 29.90 ± 1.87 %, respectively. The potential applications for PSA@PHC smart active double-layer film in food packaging were highly promising due to its outstanding properties. In terms of its application to the preservation and freshness monitoring of Ictalurus punctatus fish, the double layer film could extend the shelf life for 2 d and enable effective monitoring. [ABSTRACT FROM AUTHOR]

Grass carp are highly perishable under the action of spoilage bacteria including Aeromonas rivipollensis , Pseudomonas putida , and Shewanella putrefaciens. However, the metabolic characteristics of the three bacteria in degrading fish proteins and small molecular nutrients are unclear. In this study, we used LC-MS/MS-based peptidomics and metabolomics to detect peptides and small molecular metabolites in grass carp flesh inoculated with the three bacteria. The peptidomic results showed that A. rivipollensis and S. putrefaciens induced an overall increase in the molecular weight of peptides in grass carp flesh. S. putrefaciens tended to hydrolyze peptide bonds composed of at least one hydrophobic amino acid whereas A. rivipollensis and P. putida preferred hydrolyzing Xaa-serine bonds. The metabolomic results showed that amino acid metabolism and nucleotide metabolism are among the most enriched pathways of differential metabolites. P. putida and S. putrefaciens were active in decomposing amino acids and nucleosides, respectively. Besides, lipid metabolism also plays an important role in grass carp spoilage, representing as the degradation from phosphatidylcholine to lysophosphatidylcholine by the three bacteria. To conclude, this study revealed distinct metabolic characteristics of the three bacteria in degrading proteins and small molecular metabolites, and thus contribute to the understanding of fish spoilage mechanisms. [Display omitted] • A.rivipollensis and S. putrefaciens induced overall increases in peptide MW in fish. • Cleavage sites of S. putrefaciens proteases were more diverse than other bacteria. • A.rivipollensis and P. putida preferred to break Xaa-serine bonds in fish proteins. • S.putrefaciens induced rapid degradations from nucleosides to purine bases. • Bacteria degraded phosphatidylcholine in grass carp flesh to lysophosphatidylcholine. [ABSTRACT FROM AUTHOR]

Bacillus cereus is a ubiquitous foodborne pathogen commonly found in various foods. Its ability to form spores, biofilms and diarrhoeal and/or emetic toxins further exacerbates the risk of food poisoning. Violacein is a tryptophan derivative with excellent antibacterial activity. However, the knowledge on the antibacterial action of violacein against B. cereus was lacking, and thus this study aimed to investigate the antibacterial activity and mechanism. The antibacterial results demonstrated that minimum inhibitory concentration and minimum bactericidal concentration of violacein were 3.125 mg/L and 12.50 mg/L, respectively. Violacein could effectively inhibit planktonic growth, spore germination and biofilm formation of B. cereus (P < 0.001). Meanwhile, violacein significantly downregulated the expression of toxin genes, including nheA (P < 0.05), nheB (P < 0.001), bceT (P < 0.01), cytK (P < 0.001), hblC (P < 0.001) and hblD (P < 0.001). Results of extracellular alkaline phosphatase, nucleotide and protein leakage assays and scanning and transmission electron microscopy observation tests showed violacein destroyed cell walls and membranes of B. cereus. In addition, 6.25 mg/kg of violacein could significantly inhibit B. cereus in grass carp fillets (P < 0.05). These results demonstrate that violacein has great potential as an effective natural antimicrobial preservative to control food contamination and poisoning events caused by B. cereus., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Fresh fish is a perishable food in which chemical (namely oxidation) and microbiological degradation result in undesirable odor. Non-processed fish (i.e., raw fish) is increasingly commercialized in packaging systems which are convenient for its retailing and/or which can promote an extension of its shelf-life. Compared to fish sent to its retail unpackaged, fish packaging results in a modification of the gaseous composition of the atmosphere surrounding it. These modifications of atmosphere composition may affect both chemical and microbiological degradation pathways of fish constituents and thereby the volatile organic compounds produced. In addition to monitoring Total Volatile Basic Nitrogen (TVB-N), which is a common indicator to estimate non-processed fish freshness, analytical techniques such as gas chromatography coupled to mass spectrometry or techniques referred to as “electronic nose” allow either the identification of the entire set of these volatile compounds (the volatilome) and/or to selectively monitor some of them, respectively. Interestingly, monitoring these volatile organic compounds along fish storage might allow the identification of early-stage markers of fish alteration. In this context, to provide relevant information for the identification of volatile markers of non-processed packaged fish quality evolution during its storage, the following items have been successively reviewed: (1) inner atmosphere gaseous composition and evolution as a function of fish packaging systems; (2) fish constituents degradation pathways and analytical methods to monitor fish degradation with a focus on volatilome analysis; and (3) the effect of different factors affecting fish preservation (temperature, inner atmosphere composition, application of hurdle technology) on volatilome composition.

Microbial spoilage of fish is attributed to quorum sensing (QS)-based activities. QS is a communication process between the cells in which microorganisms secrete and sense the specific chemicals (autoinductors, AIs) that regulate proteolysis, lipolysis, and biofilm formation. These activities change the organoleptic characteristics and reduce the safety of the products. Although the microbial community of fish is diverse and may consist of a range of bacterial strains, the deterioration of fish-based products is attributed to the growth and activity of Pseudomonas spp. This work summarizes recent advancements to assess the influence of QS mechanisms on seafood spoilage by Pseudomonas spp. The quorum sensing inhibition (QSI) in the context of fish preservation has also been discussed. Detailed recognition of this phenomenon is crucial in establishing effective strategies to prevent the premature deterioration of fish-based products. [ABSTRACT FROM AUTHOR]

This review aims to elucidate advanced nanostructures and explore their potential applications in enhancing the shelf life of fresh or processed seafood products. Biopolymer films, incorporating new nanomaterials, can serve as edible coatings to effectively preserve the quality of seafood. Nanotubes, nanogels, functionalized nanocrystals have demonstrated their efficacy in protecting fatty fish samples against oxidation, showcasing their practical utility with specific antimicrobial activities. Nanostructured lipid carriers, exemplified by nanoethosomes and nanophytosomes, are considered as viable alternatives to nanoemulsions. The combination of nanotechnological treatments with thermal thawing or nonthermal applications has been empirically proven to improve quality. Furthermore, the study highlights the existence of novel nanomaterials (nanoparticles embedded in ice, nanoprecipitates, 3D nanonetworks, nanosheets) awaiting exploration. It also emphasizes the mechanisms governing the existing nanomaterials, necessitating a more detailed investigation. In essence, this research not only sheds light on the existing potential of advanced or novel nanosytems but also underscores the need for a deeper understanding of their undiscovered counterparts and the mechanisms guiding their efficacy. [Display omitted] • Nanomaterial shape and size influence cell wall disruption functions. • New forms of nanoantimicrobials will be more effectively used in future. • Combination of nanomaterials are promising for synergistic effect on spoilage bacteria. • Improvement of nanomaterial properties with nonthermal methods enhance protection. • Lipid-based nanovehicles could be used as an ingredient in minced meat. [ABSTRACT FROM AUTHOR]

Two edible coatings (gelatin coating and ginger essential oil-gelatin coating) were prepared to maintain the flavor quality of fish fillets at two storage temperatures (4 °C and 25 °C). The effects of coating on fish fillets were evaluated by detecting the physical properties, microstructure, microbial properties, volatile flavor and taste flavor of fish. In the same coating method, fish fillets stored at 4 °C showed better effect than that at 25 °C on maintain water content, color and texture, however, fish fillets stored at 25 °C were closer to fresh fish in volatile flavor and taste flavor than that at 4 °C; whatever the storage temperature, coating could slow down the growth of fish microorganisms, maintain water content, color, texture, volatile flavor and taste flavor of fish fillets; GGC exhibited better effect on maintain flavor quality than GC.

As global biodiversity faces unprecedented threats, the conservation of genetic diversity has become a priority in preserving ecosystems and species. Fish genetic preservation, a critical component of aquatic biodiversity conservation, has seen significant advancements through cryobanking strategies. This communication provides an overview of the different cryobank strategies and discusses the practical applications and challenges of cryopreservation in fish genetic resources. For years, cryopreservation in fish production was primarily used for genetic resource storage, beginning in the 1990s. It became essential for breeding programs, especially with advancements in genomics and the selection for disease resistance. However, the application of cryopreservation was largely limited to off-site facilities until 2016, when IMV Technologies introduced production-based laboratories directly into fish hatcheries. This shift allowed cryopreservation to become a more integrated part of fish farming operations. Today, various organizational models for cryopreservation services exist worldwide. In the United States and Denmark, public institutes offer off-site cryopreservation services. In France, cooperatives provide similar support, while in Chile and Norway, private companies handle these services. IMV Technologies offers an innovative on-site service model, setting up laboratories within farms. This enables farmers to collect, freeze, and store sperm on-site, providing them with more flexibility and control over their genetic resources. These developments in cryobanking strategies highlight the need for significant European and national funding to expand and optimize cryobank infrastructure. Establishing and maintaining cryobanks requires substantial resources, and financial support is crucial to fully realize the potential of these technologies. Adequate funding would not only facilitate broader adoption of cryopreservation but also improve the management of genetic resources, ultimately contributing to the sustainability of fish populations. In conclusion, while significant progress has been made in fish genetic preservation, ongoing research and collaboration are essential to overcome existing barriers and ensure the long-term sustainability of aquatic genetic resources. This communication serves as a call to action for researchers, policymakers, and conservationists to prioritize and invest in the development of robust cryobank strategies as part of global efforts to safeguard our planet's aquatic heritage. [ABSTRACT FROM AUTHOR]

Active packaging has been recognized as an effective approach to extend the shelf life of food, but the rapid release of active substances limits the preservation effect. In this study, gallic acid (GA)-loaded ovalbumin (OVA)/chitosan (CS) nanoparticles with slow-release properties were prepared and embedded into the pectin matrix to refine the rapid release of GA in the pectin and elongate the shelf life of salmon fillets. Our results showed that GA could be released continuously from the OVA/CS nanoparticles. The pectin film incorporated with GA-loaded OVA/CS nanoparticles exhibited good light barrier and mechanical properties. The opacity value of the film reached 1.65 ± 0.06 UA/mm, and the tensile strength and elongation at break were 15.97 ± 1.55 MPa and 7.29 ± 0.42 %, respectively. In addition, the pectin film combined with GA-loaded OVA/CS nanoparticles showed improved antibacterial activity against two common biogenic amine-producing bacteria (Morganella morganii and Escherichia coli). Moreover, the nanocomposite film delayed salmon fillets' biogenic amine generation, and the shelf life was extended by 3 days compared with the control group. These promising properties supported using the GA-loaded OVA/CS nanoparticle-pectin films as preservation materials for fish. • Gallic acid-loaded ovalbumin/chitosan nanoparticles with sustained-release effect. • Nanocomposition film consisted of pectin and the nanoparticles was prepared. • The nanocomposition film endowed the salmon fillets with extended shelf-life. • The film delayed the growth of biogenic amines and amine-producing bacteria. [ABSTRACT FROM AUTHOR]

Given the growing emphasis on food safety, the need for functionalized packaging is becoming more prominent. Cinnamon essential oil (CEO)-based Pickering emulsions can impart excellent anti-bacterial and anti-oxidant activities to collagen films through slow-release actives, but the resultant films exhibit reduced water resistance and mechanical properties that may limit their application. In this study, oxidized mulberry extract (OME) was prepared by laccase oxidation and used as an enhancer to improve the physicochemical properties of CEO-based Pickering emulsion collagen films. The incorporation of OME enhanced the tensile strength (79.18–106.35 MPa) and water resistance (water vapor permeability, 2.82–2.30 × 10−11 (g·m−1·s−1·Pa−1); water sorption, 524.57%–201.28%) of the films. The films also exhibited superior light-blocking, antioxidant, and antibacterial activities as well as pH sensitivity. When the COL-PE/OME 4 film was used for fish preservation, a four-day extension of shelf life was observed and the film showed a visible color change (ΔE > 5) from red (day 0) to blackish-green (day 12) reflecting the degree of freshness of the stored fish. These findings indicate the potential of the functionalized collagen films for fish preservation and indicators of freshness. [Display omitted] • Oxidized mulberry extract (OME) was prepared using laccase oxidation. • OME was incorporated into Pickering emulsion-based collagen films. • The mechanical and barrier properties of films were improved after OME incorporation. • The films showed enhanced antibacterial/antioxidant activity and pH sensitivity. • The films have significant potential in fish preservation and indicating freshness. [ABSTRACT FROM AUTHOR]

The high susceptibility of harvested fresh fish to immediate deterioration has resulted in the fundamental need for fish preservation to maintain its nutritional quality, minimize changes in its physical appearance, taste and lengthen shelf life. The insecticide, pirimiphos methyl (actellic dust) has been utilized in the storage of dried products against insect infestation, thereby increasing their shelf life. This study investigated the effect of pirimiphos methyl on the proximate and mineral composition of Synodontis nigrita and Tilapia mariae in Jamieson River which were purchased from the fish landing site in Sapele Delta State, Nigeria. The fish samples were divided into three batches of fresh samples (batch I), oven – dried samples (batch II) and actellic dust treated samples (batch III). The proximate composition (moisture, protein, fat, ash, crude fibre, and carbohydrate) and mineral content (sodium, potassium, calcium, and magnesium) of the samples were determined using the AOAC standard methods. Results showed that actellic dust treatment greatly increased the protein (19.35 to 23.31%), fat (8.12% to 22.31%), and raw fibre content (0.69 to 8.03%) in S. nigrita and protein (7.09 to 25.46%), fat (5.13 to 11.70%), and raw fibre content (3.40 to 14.23%) in T. mariae. The mineral elements analyzed showed no well-defined order across the treatment levels with potassium being the most abundant mineral element in all fish samples. Actellic dust has been shown to improve the proximate composition and shelf life of both fish species studied, and its use as a fish preservative is therefore recommended.

Microbial spoilage of fish is attributed to quorum sensing (QS)-based activities. QS is a communication process between the cells in which microorganisms secrete and sense the specific chemicals (autoinductors, AIs) that regulate proteolysis, lipolysis, and biofilm formation. These activities change the organoleptic characteristics and reduce the safety of the products. Although the microbial community of fish is diverse and may consist of a range of bacterial strains, the deterioration of fish-based products is attributed to the growth and activity of Pseudomonas spp. This work summarizes recent advancements to assess the influence of QS mechanisms on seafood spoilage by Pseudomonas spp. The quorum sensing inhibition (QSI) in the context of fish preservation has also been discussed. Detailed recognition of this phenomenon is crucial in establishing effective strategies to prevent the premature deterioration of fish-based products.

Summary: Rivulidae comprises a family of fish largely distributed in Brazil that includes 201 species, of which 125 are considered endangered. This fact emphasizes the need for development of conservation strategies including studies on genetics and reproduction. In this paper, we describe aspects of biology and reproduction of the rivuliid species Hypsolebias sertanejo. We outline the reproductive behaviour of this species under laboratory conditions, analyze ploidy status by flow cytometry, describe reproductive behaviour and performance and test dry and wet incubation of eggs. Although H. sertanejo showed well known patterns of reproductive behaviour, we verified many peculiarities inherent to its reproductive biology. As expected, most individuals were diploid (87.71%), however 14.29% were considered mosaics. Although no sterility was observed within mosaics, infertility of these fish was not fully evaluated. Hatching rate of the eggs collected was very low following both dry and wet incubation (5.04 and 3.79%, respectively). These results provide interesting information regarding the reproductive success of this species, and suggest that chromosomal abnormalities described may reduce the survival of H. sertanejo under natural conditions, limiting the perpetuation of this species, and emphasizing the need for more preservation efforts, including artificial propagation and gene banking. [ABSTRACT FROM AUTHOR]

Glucose oxidase (GOx) with high enzyme activity at low temperature (4°C) is potentially useful for food preservation, especially for aquatic products preservation. A cold-active GOx with approximately 83% similarity to known protein sequences, was isolated from Penicillium sp. MX3343 and expressed in Pichia pastoris X33. Through high cell density fermentation, the yield of recombinant enzyme (named GOxP5) reached 458.6 U/mL. GOxP5 showed optimal activity at 30°C and pH 5.5, and was stable at a broad pH range from pH 2–6. Moreover, GOxP5 could maintain 72% maximum activity at 4°C, suggesting its application for the preservation of aquatic products at low-temperatures. Importantly, GOxP5 showed a good antimicrobial effect against common fish pathogenic bacteria (Listeria monocytogenes and Vibrio parahaemolyticus). Moreover, sensory, microbiological (total bacterial count), and physicochemical (total volatile basic nitrogen and pH) systematic analyses proved GOxP5 to be an excellent freshness preserving agent in the context of the grass carp. These favorable enzymatic properties of GOxP5 make it potentially useful in food biopreservation, and the effect was better compared to the commonly used chemical preservatives.

Glucose oxidase (GOx) with high enzyme activity at low temperature (4°C) is potentially useful for food preservation, especially for aquatic products preservation. A cold-active GOx with approximately 83% similarity to known protein sequences, was isolated from Penicillium sp. MX3343 and expressed in Pichia pastoris X33. Through high cell density fermentation, the yield of recombinant enzyme (named GOxP5) reached 458.6 U/mL. GOxP5 showed optimal activity at 30°C and pH 5.5, and was stable at a broad pH range from pH 2–6. Moreover, GOxP5 could maintain 72% maximum activity at 4°C, suggesting its application for the preservation of aquatic products at low-temperatures. Importantly, GOxP5 showed a good antimicrobial effect against common fish pathogenic bacteria (Listeria monocytogenes and Vibrio parahaemolyticus). Moreover, sensory, microbiological (total bacterial count), and physicochemical (total volatile basic nitrogen and pH) systematic analyses proved GOxP5 to be an excellent freshness preserving agent in the context of the grass carp. These favorable enzymatic properties of GOxP5 make it potentially useful in food biopreservation, and the effect was better compared to the commonly used chemical preservatives. [ABSTRACT FROM AUTHOR]

This study aimed to increase the antibacterial activity of chitosan-polylactic acid (PLA) composite film by adding nisin and ethylenediaminetetraacetic acid (EDTA). We evaluated the mechanical, physicochemical, and antibacterial properties of various PLA composite films, as well as the enhancement effect of PLA composite films with EDTA + nisin on the preservation of grouper fillets. Films of PLA alone, PLA plus chitosan (C5), PLA plus nisin + EDTA (EN2), and PLA plus chitosan plus nisin + EDTA (C5EN1 and C5EN2) were prepared. The addition of EDTA + nisin to the chitosan-PLA matrix significantly improved the antibacterial activity of the PLA composite film, with C5EN1 and C5EN2 films showing the highest antibacterial activity among the five films. Compared with the fish samples covered by C5, the counts of several microbial categories (i.e., mesophilic bacteria, psychrotrophic bacteria, coliforms, Aeromonas, Pseudomonas, and Vibrio) and total volatile basic nitrogen content in fish were significantly reduced in the samples covered by C5EN1. In addition, the counts of samples covered by C5EN1 or C5 were significantly lower compared to the uncovered and PLA film-covered samples.

Pepsin soluble collagen (PSC) was extracted from blue shark (Prionace glauca) skin and was used for chitosan–collagen composite coating to investigate coating effects on fresh red porgy (Pagrus major) fillet quality during storage at 4°C. Total volatile basic nitrogen (TVB‐N), thiobarbituric acid (TBA), pH, K value, drip loss, and sensory evaluation scores were measured as deterioration indexes. Results show that coating by 1% of chitosan solutions containing 0.0%–0.8% of PSC significantly improved most deterioration indexes. Coating by 1% of chitosan solution containing 0.8% of PSC yielded the best results for K value, drip loss, and sensory evaluation, although the other indexes show no clear PSC concentration dependence. These results indicate 1% of chitosan solution containing 0.8% of PSC as the best coating formulation examined in this study. Practical applications: Aquatic products have high contents of water and protein. Their qualities are likely to decline because of endogenous chemical and enzyme reactions, and also because of the role of spoilage and pathogenic microorganisms during storage. The edible collagen and chitosan coating suggested by this research is biodegradable, biocompatible, cost effective, and is able to meet the requirements for food quality and storage duration. Pepsin soluble collagen (PSC) is an aquatic product processing by‐product that makes the maximum use of resources. As described herein, a composite formulation comprising collagen and chitosan improves preservation effects of different types of coatings. A more high‐quality and effective edible coating formulation was obtained, thereby extending the red porgy fillet shelf life. [ABSTRACT FROM AUTHOR]

Fish and fishery products being highly perishable and readily susceptible to chemical and microbial deterioration leads to reduction in the quality, wastage and economic loss. Maintenance of high-quality fish, so calls for adequate, effective and affordable preservative techniques of these nutritious resources. In the present study, fish was treated with four different treatments namely Crude extract of green tea (GT1), Concentrated extract of green tea (GT2), Crude extract of Black tea (BT1) and Concentrated extract of black tea (BT2). Tea is a very good source of polyphenols including bioactive chemicals, flavonoids, and catechinsand their derivatives. The results of present research shodwed that highest (98.46±1.24 mg TAE g-1 dw) and lowest (49.60±1.95 mg TAE g-1dw) phenolic content were found in aqueous solutions of GT2 and BT1 respectively. Total phenolic content in water extracts has shown in the following order GT2>BT2>GT1>BT1. Among the various tea extract tested, GT2 exhibited greater antimicrobial activity followed by BT2, GT1 and BT1. [ABSTRACT FROM AUTHOR]

The marine products export substantially increased from 2,96,277 tons of worth Indian Rs. 3,501 crores in the year 1995-96 to 13,77,244 ton of Rs. 45,107 crores in the year 2017-18. Cephalopods were used to be treated often as part of discardable by-catch in India, but now they have an upgraded because of their export. The squid is an economically important cephalopod in India contributes nearly 7.3% share of total Indian marine products export. The Indian squid (Uroteuthis duvauceli) is the dominant species, contributes about 97% catch all over the country, where as other species represents are Sepioteuthis lessoniana and Doryteuthis sp. Among total squid landings almost 90% comes from the west coast of India. The annual landing of squid was 1,14,886 tons in 2016 and it was raised to 1,31,774 tons in proceeding year i.e. 2017. During year 1995-96 the export of frozen squid recorded 45,025 tons of Rs. 320 Cr whereas in the year 2017-18, it was increased to 1,00,845 tons of Rs. 2452 Cr. The squid has many advantages over fish, such as white flesh, high yield and very low fat content. The shelf life is a major problem of the captured squids; hence mostly they are used for fresh consumption by local population. However to maintain its quality and nutritional value several techniques of fish preservation need to be developed. [ABSTRACT FROM AUTHOR]

This research prepared chitosan–PLA plastic films by extrusion, analyzed the physical and mechanical properties and antibacterial activity of the fabricated plastic films, and used them to preserve grouper fillet. We added chitosan (220 kDa, 93% DD) in the weight ratio of 0.5–2% into the PLA to prepare the chitosan–PLA films. With the increasing chitosan dosage, both the water vapor transmission rate and moisture content of chitosan–PLA films increased. Among the three doses of chitosan (0.5%, 1%, and 2%) added to PLA, 0.5% chitosan–PLA film had the highest antibacterial activity. This plastic film had an inhibitory efficiency of over 95% against Escherichia coli, Pseudomonas fluorescens, and Staphylococcus aureus. The action of covering the fish fillet with 0.5% chitosan–PLA film significantly reduced several microbes’ counting (i.e., mesophiles, psychrophiles, coliforms, Pseudomonas, Aeromonas, and Vibrio) and total volatile basic nitrogen (TVBN) value in the grouper fillets stored at 4 °C. Thus, such action prolongs the fish fillets’ shelf life to up to at least nine days, and this 0.5% chitosan–PLA film shows promising potential for preserving refrigerated fish.

Abstract Nitric oxide (NO) and nitrogen (N 2) (0.4/99.6, v/v) were flushed in a modified atmosphere packaging (NO-MAP) to preserve tilapia fillets at 4 °C. Compared with vacuum packaged (VAP) samples, NO-MAP samples had higher redness values, lower rigor extent and less drip loss. After storage of 15 days, nitrate levels in the fillets were lower than that of the nitrate/nitrite processed foods like ham and below the China National Standard of the maximum permitted limit. In addition, NO-MAP was more effective in improving tilapia quality than NO euthanasia of live tilapia and saturated NO solution immersion of tilapia fillets. The results suggested that NO-MAP could be a potential novel MAP technique in storage of tilapia fillets to improve the product quality, extend the shelf-life and reduce food safety risks. This technique also has the potential to be used for other fresh fish or meat packaging and storage. Highlights • Nitric oxide-modified atmosphere packaging (NO-MAP) was used in tilapia fillets. • NO-MAP improved fillets quality causing higher redness values and longer shelf-life. • NO-MAP caused less nitrate after the storage thus reduced the food safety risks. • NO-MAP was more effective in improving fillets quality than other NO-based methods. [ABSTRACT FROM AUTHOR]

The high susceptibility of harvested fresh fish to immediate deterioration has resulted in the fundamental need for fish preservation to maintain its nutritional quality, minimize changes in its physical appearance, taste and lengthen shelf life. The insecticide, pirimiphos methyl (actellic dust) has been utilized in the storage of dried products against insect infestation, thereby increasing their shelf life. This study investigated the effect of pirimiphos methyl on the proximate and mineral composition of Synodontis nigrita and Tilapia mariae in Jamieson River which were purchased from the fish landing site in Sapele Delta State, Nigeria. The fish samples were divided into three batches of fresh samples (batch I), oven - dried samples (batch II) and actellic dust treated samples (batch III). The proximate composition (moisture, protein, fat, ash, crude fibre, and carbohydrate) and mineral content (sodium, potassium, calcium, and magnesium) of the samples were determined using the AOAC standard methods. Results showed that actellic dust treatment greatly increased the protein (19.35 to 23.31%), fat (8.12% to 22.31%), and raw fibre content (0.69 to 8.03%) in S. nigrita and protein (7.09 to 25.46%), fat (5.13 to 11.70%), and raw fibre content (3.40 to 14.23%) in T. mariae. The mineral elements analyzed showed no well-defined order across the treatment levels with potassium being the most abundant mineral element in all fish samples. Actellic dust has been shown to improve the proximate composition and shelf life of both fish species studied, and its use as a fish preservative is therefore recommended. [ABSTRACT FROM AUTHOR]

Cold acclimation has a tremendous impact on the survivability and the freshness of turbot when presented to consumers for sale. In the present study, to better understand the response of turbot to cold acclimation, physiological parameters determination, two-dimensional-based proteomic analysis and the expression of target genes by quantitative real-time PCR were analyzed. The results of physiological parameters indicated that the levels of glucose, ATP and cortisol, and the activities of lysozyme, catalase (CAT) and superoxide dismutase (SOD) were elevated. Moreover, the liver damage may be determined due to the increase of glutamic-oxalacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) in serum. Furthermore, a total of sixteen differentially accumulated proteins were identified, which are mainly involved in carbohydrate and energy metabolism. Based on these data, we concluded that turbot accelerate the glycogen hydrolysis in liver and muscle to increase the glucose level in serum and promote the energy metabolism, enhance innate immune and heighten the antioxidant capacity to respond to cold acclimation. Meanwhile, the cold acclimation can also cause adverse effect to the innate immune system and liver of turbot. These results are helpful in understanding the response of turbot to cold acclimation and in providing the theoretical base for applying fish cold acclimation in transport. [ABSTRACT FROM AUTHOR]

This manuscript evaluates the potential application of active nanocomposite films based on soy protein isolate (SPI)-montmorillonite (MMT)-clove essential oil (CEO) to the preservation of muscle fillets of bluefin tuna ( Thunnus thynnus ) during refrigerated storage, and furthermore analyzes whether the clay diffuses from the package to food. SPI films with: CEO (SPI-CEO), MMT (SPI-MMT), or both CEO and MMT (SPI-MMT-CEO), were prepared and used to cover tuna fillets during 17 days of storage at 2 °C. Polyethylene films were also used as control. Protein films nanoreinforced with 10 g MMT/100 g SPI and activated with CEO were able to decrease microbial growth (evaluated by TVBN and microorganism counts) and lipid autooxidation (evaluated according to the TBA index, FTIR and color parameters) of tuna fillets during the storage period studied. The presence of clay seemed to favor the release of the active principles of clove oil by prolonging its antimicrobial (especially effective to inhibit Pseudomonas spp.) and antioxidant activity over time without observing the diffusion of the clay's own metals (Si and Al) from the nanocomposite materials to the muscle of fish. These results are encouraging for the use of nanocomposite films in food packaging. [ABSTRACT FROM AUTHOR]

Pectin and starch crystals were modified by ethyl gallate and octadecyl-trimethoxysilane, respectively, followed by using acylated pectin (AP) and alkylated starch crystals (ASCs) as bioactive reagents and hydrophobic enhancers to improve the physiochemical properties of gelatin-based films and evaluate their coating preservation effects on golden pomfret. The properties of AP and ASC were investigated by Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–vis), proton-nuclear magnetic resonance (1H NMR) and X-ray diffraction (XRD). The ethyl-gallate-modified pectin/gelatin (AP/G) containing 3 % ASC (AP/G/ASC-3 %) was shown to have the maximum tensile strength and Young's modulus of all the tested composite films. The AP/G containing 10 % ASC exhibited a water contact angle higher than 94°, coupled with a significant improvement in UV-shielding efficiency. FTIR and SEM analysis of the AP/G/ASC-3 % film indicated that the molecular interactions in the composite film components were noncovalent linkages, including hydrogen bonds, hydrophobic interactions, and electrostatic interactions, contributing to homogeneous and smooth microstructures. Additionally, the solutions of AP/G and AP/G/ASC composite films presented obvious antioxidant and antibacterial activities against Escherichia coli and Staphylococcus aureus. Furthermore, the AP/G and AP/G/ASC active coatings could effectively inhibit lipid oxidation and improve the textural acceptability of golden pomfret (Trachinotus blochii) fillets during 4 °C storage. • Alkylated starch crystal (ASC) and acylated pectin (AP) were synthesized as enhancers. • ASC and AP enhanced comprehensive properties of gelatin (G)-based composite film. • Gold pomfret shelf life was effectively prolonged via ASC/AP/G coating. [ABSTRACT FROM AUTHOR]

Cuttlefish and squid ink are generally discarded as wastes during their processing. Melanin free ink (MFI) of squid is reported to possess bio-functional properties. This investigation was aimed to study the MFI of cuttlefish (Sepia prabahari) as an antioxidant to increase the stability of chilled fatty fish. Melanin from the cuttlefish ink was removed after dilution with distilled water (1:1) by ultra centrifugation to obtain MFI. The yield of MFI from cuttlefish ink after 1:1 dilution was estimated as 70% and the protein content of the MFI extract was 2.3±0.2mg/ml. The in-vitro antioxidative assay performed showed that the MFI had a DPPH radical scavenging activity of 20.12% at 40μg/ml of protein concentration and metal chelating activity of 22.82% at 5μg/ml of protein concentration. Although the in-vitro antioxidative activity expressed by MFI was quite low, the same was used to assess the in-vivo antioxidant assay in minced sardine meat model system. The result showed that the maximum TBARS value obtained was 2.26mg malonaldehyde/kg for the MFI treated sample and 12.93 mg malonaldehyde/kg for the control. This study thus indicated that lipid oxidation was retarded by MFI of the cuttlefish and could serve as a natural antioxidant to preserve fatty fishes during chilled storage. [ABSTRACT FROM AUTHOR]

Today, extending the shelf-life of fish, while retaining the organoleptic properties of the product, is still a challenge. To compare the effectiveness of conventional and hyperbaric cold storage in preserving fish quality, we stored Cape hake loins at 5 °C, both at atmospheric pressure and at 50 MPa. After 7 days of storage, microbial counts and total volatile basic-nitrogen content in conventionally refrigerated samples exceeded the limits recommended for consumption. By contrast, hyperbaric cold storage maintained these parameters unaltered, although it produced drip losses close to 5% and increased the shear resistance and whiteness of the raw samples by 44% and 9%, respectively. Nevertheless, after cooking, weight losses were less than half of those of the control loins and whiteness differences disappeared. Consequently, the sensorial analysis could only find moderate differences between the samples before and after hyperbaric storage. These results clearly prove that hyperbaric cold storage was more efficient than conventional refrigeration for the preservation of hake loins. Industrial relevance Hyperbaric cold storage opens interesting new doors for the fish-processing industry. Thus, it could be employed in different sections of the cold chain: on board, immediately after caught; at the food industry, during processing; on ship or trunk transport for long-distance markets; at school or hospital kitchens; at restaurants; or even at home. The increased cost resulting from hyperbaric storage should be overcome by an extended shelf life of a high-quality product. [ABSTRACT FROM AUTHOR]

The gelatin (GL) based film with high antioxidative and antibacterial activity and emulsifier-free was developed. The tensile strength (TS) and elongation at break (EAB) of gelatin films could be improved by adding TEMPO-oxidized cellulose nanofibers (TCNFs). When the content of epigallocatechin gallate (EGCG) and carvacrol (CAR) reached 20 mg and 500 mg, the EAB of the composite film was 61.25%, which was much higher than that of gelatin film (28.73%). EGCG and CAR could improve UV barrier performance of GL/TCNFs films. GL/TCNFs/20EGCG/500CAR film allowed DPPH· and ABTS+ free radical scavenging rates to reach 92.6% and 90.6%, and the diameters of inhibition zones of E. coli and S. aureus were 22.28 mm and 42.58 mm, which showed that EGCG and CAR had synergistic effects. In the coating preservation of sea bass fillets, it also showed excellent inhibition of bacterial proliferation including Pseudomonas aeruginosa , H 2 S-producing bacteria as well as yeast and mold. TVB-N and TBA of control group were 15.21 mg/100g and 0.353 mg MDA/kg respectively on day 6, while lower values of 5.41 mg/100g and 0.124 mg MDA/kg respectively were recorded for GL/TCNFs/EGCG/500CAR group at the end of storage. All these results indicated that GL/TCNFs/EGCG/CAR film has potential application in fish preservation and is an environmentally friendly active food packaging system. • TCNFs could give a huge boost to the mechanical behavior of gelatin films. • GL/TCNFs/EGCG/CAR film was homogeneous without emulsifying agents. • EGCG and CAR greatly enhanced the antioxidative and antimicrobial effect of films with synergy. • GL/TCNFs/EGCG/CAR coating showed excellent inhibition of fat oxidation and microbial growth. [ABSTRACT FROM AUTHOR]

Hydrogels have become promising materials for food packaging due to their unique microstructure. However, hydrogel materials suitable for seafood preservation have rarely been reported. In this study, a tamarind polysaccharide-polyvinyl alcohol hydrogel with the ability to maintain seafood freshness was prepared and characterized. The hydrogel possesses quick self-healing, good tissue fitting, and freezing tolerance capability. Moreover, a peeling force of only 0.1 N between the hydrogel and the fillet tissue confirmed the non-stick properties. The FTIR characteristic peak at 1600 cm−1 and 1450 cm−1 proved the ester bond-based chemical cross-linking of the hydrogel. Release profiles at pH 6.0 to 8.0 verified the pH-responsive release of quorum-quenching (QQ) enzymes over 120 h, which enabled the hydrogel to achieve biofilm and protease inhibitory activities. In vivo spoilage tests showed that the shelf life of hydrogel-coated red snapper fillets was extended by >3 days. These results illustrate the potential of the prepared hydrogel as functional packaging for seafood preservation. [Display omitted] [ABSTRACT FROM AUTHOR]