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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]

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]

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]

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]

Controlled release of curcumin by a pH-sensitive carrier provides long-term preservation, which extends the shelf lives of fish. FTIR, XRD, 1H NMR, zeta potential, swelling ratio, and TG analyses indicated that a pH-sensitive starch-based carrier with a narrow pH-sensitivity range (pH 6–7) was fabricated from the carboxymethyl starch grafted with methacrylic acid and then cross-linked with β-cyclodextrin to achieve dual functionality. FTIR, XRD, and fluorescence spectroscopy revealed that the mechanism by which curcumin was encapsulated in the starch-based carriers involved hydrophobic interactions and intermolecular hydrogen bonding. The encapsulated curcumin showed improved stability, higher antioxidant activity, antibacterial activity, and biocompatibility. The pH, TVB-N, TVC, and drip loss tests confirmed that the use of the carrier-curcumin complex at a concentration of 10 mg/mL for the preservation of yellow catfish extended the shelf life for 2–4 days during cold storage and improved the storage quality of the resulting fillets. This work provides a dual functionality strategy for constructing a pH-sensitive starch-based carrier to deliver curcumin and offers a promising choice for fish preservation.Graphical Abstract: Controlled release of curcumin by a pH-sensitive carrier provides long-term preservation, which extends the shelf lives of fish. FTIR, XRD, 1H NMR, zeta potential, swelling ratio, and TG analyses indicated that a pH-sensitive starch-based carrier with a narrow pH-sensitivity range (pH 6–7) was fabricated from the carboxymethyl starch grafted with methacrylic acid and then cross-linked with β-cyclodextrin to achieve dual functionality. FTIR, XRD, and fluorescence spectroscopy revealed that the mechanism by which curcumin was encapsulated in the starch-based carriers involved hydrophobic interactions and intermolecular hydrogen bonding. The encapsulated curcumin showed improved stability, higher antioxidant activity, antibacterial activity, and biocompatibility. The pH, TVB-N, TVC, and drip loss tests confirmed that the use of the carrier-curcumin complex at a concentration of 10 mg/mL for the preservation of yellow catfish extended the shelf life for 2–4 days during cold storage and improved the storage quality of the resulting fillets. This work provides a dual functionality strategy for constructing a pH-sensitive starch-based carrier to deliver curcumin and offers a promising choice for fish preservation. [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]

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]

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]

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]

By-products of a native fruit of the Argentina northwest have been valorized for the extraction of both pectin and bioactive extracts with the aim of developing antioxidant films with potential application as food packaging materials. Initially, the composition and antioxidant properties of polyphenol-rich, anthocyanin-rich, and pectin extracts obtained from the seed and peel of Solanum betaceum (chilto) red fruits were characterized. Based on their higher antioxidant properties, peel extracts were selected as active compounds and incorporated in a film-forming matrix based on the pectin extract. Dry films were evaluated concerning their morphological, optical, thermal, mechanical, and water barrier properties. The developed antioxidant films were directly applied on salmon fillets, effectively improving their shelf-life and reducing lipid and protein oxidation during 10 days of storage at 4 °C. It was also found that the films containing peel-polyphenolic extract were the most promising, in agreement with their better barrier properties. [Display omitted] • Pectin, anthocyanin and polyphenol enriched extracts from red chilto were characterized. • Samples with the highest content of phenolic compounds were those obtained from chilto peel. • Antioxidant pectin based films were obtained from the peel of S. betaceum fruits. • Active films showed remarkable antioxidant properties to protect salmon fillets. [ABSTRACT FROM AUTHOR]

The aim of the present study was to evaluate antioxidative activities of the encapsulated and unencapsulated bitter orange peel extract on the shelf-life of the common carp fillets during 16 days of refrigerated storage. Common carp fillets were treated with bitter orange peel extract (0.5 and 1% w/w), liposomal encapsulated bitter orange peel extract (0.5 and 1% w/w) and beta-hydroxytoluene (BHT, 100 and 200 ppm); their quality changes in terms of total volatile basic nitrogen (TVB-N), free fatty acid (FFA) peroxide value (PV), thiobarbituric acid (TBA) and sensory characteristics were investigated. Results showed that the encapsulated and pure extract and BHT could reduce chemical deterioration and lipid oxidation in the fillets compared to the control, as reflected with lower TVBN, FFA, PV and TBA values. Furthermore, common carp fillets treated with high concentration (1%) of the encapsulated bitter orange peel extract showed the lowest amount of lipid oxidation during the storage period compared with the others without any undesirable changes in sensorial attributes. [ABSTRACT FROM AUTHOR]

Wet weight is one of the most common biological descriptors collected for fisheries research. Freezing is frequently used to preserve fish prior to processing in a lab, and wet weights are often collected for thawed fish. Freezing may affect the wet weight of fish and result in biased values for weight based metrics. Our objectives were to determine the effects of three frozen storage methods, size class of fish, and duration of storage on the changes in wet weight of emerald shiner ( Notropis atherinoides ) and rudd ( Scardinius erythrophthalmus ), and how failure to account for changes in wet weight affects percent dry weight estimates. Two size classes of emerald shiner and three size classes of rudd were collected from the upper Niagara River, New York. Fish were weighed immediately after being euthanized and then glazed with water, frozen in water, or vacuum-sealed and stored at −25 °C for 3 or 6 months. After measuring post-thaw wet weight, fish were dried to a constant weight and percent dry weight was calculated based on prestorage wet weight and post-thaw wet weight. Then, we compared species specific prestorage wet weights to post-thaw wet weights for each storage method. Analysis of variance was used to investigate the effects of storage method, size class, and duration stored on wet weights of each species. Prestorage and post-thaw percent dry weights were compared to illustrate the effects of frozen storage on a commonly used weight-based metric. Emerald shiner and rudd wet weights differed from initial weights for all storage methods. Percent change in wet weight of emerald shiner was affected by interactions among storage method, size class, and duration stored, while percent change in wet weight of rudd was affected by the interaction between fish size class and storage method. Overall, storage method and size class had the greatest effects on changes in wet weight following frozen storage. Post-thaw wet weight increased from initial wet weight for fish frozen in water and decreased for vacuum-sealed and glazed fish, and smaller fish generally experienced greater changes than larger fish of the same species. Percent dry weight estimates based on post-thaw wet weights differed proportionally by −10.6–29.8% from estimates based on prestorage wet weights. Frozen storage can substantially affect weight based metrics such as percent dry weight and should be accounted for if weight is not measured prior to freezing. [ABSTRACT FROM AUTHOR]

The effect of fennel extract on the quality of silver carp ( Hypophthalmicthys molitrix) fillets, and the possible efficacy of liposomal encapsulation in the improvement of its antimicrobial and antioxidant activity during chilled storage (4 + 1°C) of the fillets were examined over a period of 15 days. Silver carp fillets were treated with pure fennel extract (0.3% and 0.5% w/v) and liposomal encapsulated fennel extract (0.3% and 0.5% w/v), and their quality changes in terms of total volatile basic nitrogen ( TVB-N), peroxide value ( PV), thiobarbituric acid ( TBA), microbial counts, and sensory properties were investigated. Fennel extract could retard the deterioration of silver carp fillets, as reflected in lower TVB-N, PV and TBA value. Moreover, the efficacy of fennel extract was improved when it was encapsulated into liposome. Silver carp fillets treated with the encapsulated fennel extract showed the lowest amount of lipid oxidation and microbial deterioration during the storage period compared with the control and pure extract treatments. Sensory evaluation revealed that shelf life of silver carp fillet was longest for samples treated with encapsulated fennel extract at 0.5% (15 days), as compared to the control (6 days) ( P < 0.05). [ABSTRACT FROM AUTHOR]

The aims of this study were to characterize an enterococci bacteriocinogenic strain and to evaluate its antimicrobial activity regarding its potential use for fish preservation. The bacterium, isolated from Odontesthes platensis in the Patagonian region of Argentine was identified as Enterococcus mundtii by means of biochemical test and 16S rDNA gene phylogenetic analyses. Furthermore, the gene that codifies mundticin KS was detected by PCR techniques. The bacteriocin was able to inhibit Gram positive and negative bacteria. In particular at pH 5.50, it was able to control the growth of fish bacterial flora. Construction of isobolograms and value of fractional inhibitory concentrations index showed that its use together with chitosan and sodium lactate (SL) exerted a synergic action on the inhibition of Listeria innocua , Shewanella putrefaciens and the psychrophilic flora isolated from fish. The use of the mentioned mixture of antimicrobials promoted strong changes on L. innocua and S. putrefaciens cellular components as shown by differential scanning calorimetry. Results suggest that the combination of the bacteriocin with chitosan and SL would be useful to reduce the amount of antimicrobials added to foods and to prevent the growth of spoilage bacteria and pathogenic microorganisms, such as Listeria monocytogenes . [ABSTRACT FROM AUTHOR]

Effect of sodium alginate coating enriched with horsemint essential oil ( HEO) on the quality of bighead carp ( Aristichthys nobilis) fillets at refrigeration temperature (4 ± 1°C) was studied. Bighead carp fillets were coated with neat sodium alginate ( SA) and sodium alginate containing 0.5 and 1% v/v of HEO and their quality changes in terms of total volatile basic nitrogen ( TVB-N), peroxide value ( PV), thiobarbituric acid ( TBA), and microbial counts were investigated. SA coating enriched with the essential oil could reduce the spoilage of the fillets and extend their shelf-life. Samples treated with SA-containing HEO showed significantly ( P < 0.05) lower TVB-N content and lipid oxidation, as reflected by lower PV, FFA and TBA values during the storage period compared with the SA and control. The treatment also reduced the degree of microbial deterioration of the fillets (about 1.5 log10 CFU/g) more efficiently than the SA. [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. [ABSTRACT FROM AUTHOR]

Aims: To study the diversity of Shewanella population in Sparus aurata fish harvested in the Aegean Sea, as well as to elucidate the influence of fish storage conditions on the selection in Shewanella strains. Methods and Results: A total of 108 strains of Shewanella spp. were isolated from Sparus aurata during storage under various conditions. Conventional phenotypic analysis along with sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) of whole cell proteins and 16S rRNA sequence analysis were used for the characterization of the strains. Numerical analysis of whole cell protein profiles showed that the isolates were separated into two distinct clusters A and B with 47% similarity. Cluster B was further subdivided into two subclusters B1 and B2 with 70% similarity. One strain could not be assigned to any of these groups. The different ability of isolates to utilize deoxycholate,d-saccharate,d-glucuronate,n-acetyl-glycosamine,d-maltose, gluconate and citrate, as well as the different type of metabolism on the Hugh and Leifson medium distinguished the different Shewanella biogroups, as these were defined by the SDS-PAGE analysis. Representative strains from the three biogroups were further investigated by 16S rRNA sequence analysis and showed more than 99·4% similarity. Conclusions: Significant similarities between the isolates and the type strains of S. baltica, S. putrefaciens and S. oneidensis at both phenotypic and molecular level signalize that the new isolates are closely related with the above Shewanella species, but do not provide a clear evidence to which of these species they belong. Significance and Impact of the Study: The lack of information about the diversity of Shewanella population in Sparus aurata fish originated from Mediterranean Sea could be confronted using conventional phenotypic techniques, SDS-PAGE analysis of whole cell proteins and 16S rRNA sequencing. [ABSTRACT FROM AUTHOR]

Quality deterioration of Nile perch iced 0, 3 and 6 h after landing was monitored to determine the effect of delayed icing on stability during storage on ice. Free fatty acids, volatile nitrogen bases and mesophilic microbial counts increased during the pre-icing duration. Delayed icing also increased the rate of lipolysis, degradation of nitrogenous compounds and growth of mesophilic microbes during subsequent storage on ice and reduced the time required for development of off odours. Psychrotrophic plate counts were, however, not affected by pre-icing duration. It was concluded that spoilage of Nile perch stored on ice is hastened by delay to ice and that mesophiles play a more important role in the spoilage of Nile perch, even when stored on ice. [Copyright &y& Elsevier]

The effects of the deacetylation degree (DD) and preparation methods for chitosan on antimicrobial activity were evaluated. Chemically prepared chitin (CH-chitin) and microbiologically prepared chitin (MO-chitin) were obtained from shrimp shells. The CH-chitin and MO-chitin were further chemically deacetylated to obtain various chitosan products of which their DD ranged from low (47–53%) through medium DD (74–76%) to high (95–98%). In addition, MO-chitin was deacetylated also by various proteases. The antimicrobial activities of these products were evaluated in medium with pH 6.0. Neither the CH-chitin, MO-chitin nor protease-deacetylated chitinous products showed any antimicrobial activity. For chitosan, antimicrobial activity increased with increasing DD, and was stronger against bacteria than against fungi. The minimal lethal concentrations (MLC) of chitosan with a high DD against Bacillus cereus , Escherichia coli , Listeria monocytogenes , Pseudomonas aeruginosa , Shigella dysenteriae , Staphylococcus aureus , Vibrio cholerae , and V. parahaemolyticus were all in the range of 50–200 p.p.m., whereas the MLC against Candida albicans and Fusarium oxysporum were 200 p.p.m. and 500 p.p.m., respectively. No antifungal activity was found at 2000 p.p.m. against Aspergillus fumigatus or A. parasiticus . Pretreatment of fish fillets (Oncorhynchus nereka ) with 1% chitosan solution (high DD) for 3 h retarded the increase in the volatile basic nitrogen content, as well as the counts for mesophiles, psychrotrophs, coliforms, Aeromonas spp ., and Vibrio spp. The shelf life was consequently extended from 5 days to 9 days. [ABSTRACT FROM AUTHOR]

Poly(hexamethylene biguanide) hydrochloride (PHMB) loaded poly(vinyl alcohol) (PVA) fibrous films were produced via electrospinning as active food packaging material. Fourier transform infrared spectroscopy analysis confirmed that PHMB has been incorporated into the PVA fibers and scanning electron microscopy analysis indicated that the fibrous films were successfully prepared. The thermal stability and antibacterial activity of PVA/PHMB fibrous films were tested. The application of fibrous films on the preservation of Japanese sea bass (Lateolabrax japonicus) during cold storage at 4 °C was investigated. Compared with the control sample, PHMB loaded PVA fibrous films effectively lowered the total viable count, inhibited Pseudomonas spp. and H 2 S-producing bacteria, as well as delayed the production of total volatile basic nitrogen. The results revealed that PVA/PHMB fibrous films had a positive effect on maintaining quality and extending the shelf life of sea bass. • Fibrous films loaded with antibacterial agent were prepared by electrospinning. • The fibrous films had excellent antibacterial properties. • The shelf life of Japanese sea bass fillets was extended by the fibrous films. [ABSTRACT FROM AUTHOR]

• Cyclolaudenol was the major constituent of the green propolis extract. • Brazilian green propolis showed great potencial for fish bilayer coating. • Antibacterial and antioxidant activity of propolis aid in the conservation of fish fillets. • The sodium alginate bilayer coating showed high sensorial acceptance. Fish deterioration imposes great economic losses and serious human health hazards. The objective of this work was to evaluate the effect of a sodium alginate bilayer coating incorporated to the green propolis extract in shelf-life, physical–chemical properties, microbiological properties and sensory acceptance of Colossoma macropomum fillets. Additionally, the chemical composition, along with the antioxidant and antibacterial activities of Brazilian green propolis extract (GPE) were investigated. GPE showed promising antioxidant and antibacterial activities. Twenty-seven metabolites were identified by gas chromatography (GC–MS), which mainly comprised terpenoids (52.14%). Cyclolaudenol was the major constituent of the GPE and it is described for the first time in green propolis extracts. C. macropomum fillets treated with the sodium alginate bilayer coating showed high sensory acceptance, reduced microbial deterioration and extended shelf-life (up to 11 days) during cold storage. Taken together, these results show that GPE can be a great alternative of a natural preservative for fish coating. [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 FROM AUTHOR]