The Effects of Sodium Alginate on Quality of Rainbow Trout (Oncorhynchus mykiss) Fillets Stored at 4 ± 2°C

Edible coating is a novel food packaging technology for controlling the growth of spoilage bacteria and chemical changes in ready-to-eat food products. Fresh fish are highly perishable foodstuffs and are very susceptible to spoilage. A sodium alginate coating was used to maintain the quality of rainbow trout fillets in chilled storage over a period of 20 days. Fillet samples were coated with an aqueous solution of 3% sodium alginate and then stored at chilled temperature (4 ± 2°C). The control and coated samples were analyzed periodically (every 5 days) for microbial (aerobic plate count and psychrotrophic count), chemical (total volatile basic nitrogen, thiobarbituric acid, peroxide value), and sensory characteristics. The results indicated that the sodium alginate coating helped protect the quality characteristics of treated fresh fish fillets and prolonged the shelf life during chilled storage of rainbow trout fillets.     

Effects of Black Cumin Oil (Nigella sativa) on Sensory,Chemical and Microbiological Properties of Rainbow Trout During 23 Days of Storage at 2 ± 1°C

In the present study, black cumin oil in the rates of 0.00 % (the control), 0.10 %, 0.40 %, 0.70 %, 1.00 % and 1.30% was added to rainbow trout feed for 144 days. After the feeding process, trout were harvested and stored at 2 ± 1°C in ice, and changes in chemical, microbiological, and sensory parameters were examined periodically. According to sensory analyses, black cumin oil used in fish meat did not cause a perceptible sensory change for all groups. Chemical analyses showed that the addition of black cumin oil to fish feed led to higher total volatile basic nitrogen content in the fish flesh. During the storage period, the highest peroxide values were observed in the groups with 1.0% and 1.3% black cumin oil added, and the lowest were in the groups with 0.0% and 0.1% added oil. The highest microbial count value was observed in the control group.     

Biochemical and Microbiological Assessment of Crucifix Crab (Charybdis feriatus) Stored at 4°C

Charybdis feriatus is a highly prized crab in the local and international markets of East Asian countries. In local markets, crabs are sold live, iced, or refrigerated at 2°C – 4°C. The present study was carried out to determine the shelf life of whole crab stored at 4°C for 192 h using a set of biochemical, microbiological, and sensorial parameters. Biochemical indicators such as the total volatile base nitrogen (TVB-N) and trimethylamine nitrogen (TMA-N) increased significantly during storage and within an acceptable limit up to 144 h. Regarding the biogenic amines, cadaverine and spermidine increased significantly (p < 0.05) during the storage period. Among them, cadaverine could be proposed as a useful spoilage indicator for this crab species. The mesophilic and psychotropic bacterial count exceeded the limit of acceptance after 144 h of storage. Sensory attributes were gradually diminished with the storage time. Sensory scores were found to correlate well with both mesophiles and psychrotrophs. Based on the results of this study, the meat quality of Charybdis feriatus can be maintained up to 144 h when properly stored at a temperature of 4°C ± 1°C.     

Characterization of the Microflora of Lightly Salted Lumpfish (Cyclopterus lumpus) Roe Stored at 5 ° C

Abstract

Numeric taxonomy analysis of 70 lactic acid bacteria (LAB) and 30 Enterobacteriaceae from lightly salted lumpfish roe, showed that Enterobacteriaceae formed three subgroups: Morganella morganii presumptive Serratia liquefaciens and Serratia plymuthica. LAB formed three subgroups of presumptive Lactococcus spp. and Carnobacterium spp. Production of off-odors and volatile sulfur compounds by twelve selected strains and three Vibrio spp. of identical origin in pasteurized roe, and of three Enterobacteriaceae in sterile fresh roe, was examined. Morganella morganii produced off-odors and volatile sulfur compounds in both pasteurized and fresh roe. One Serratia liquefaciens produced strong off-odors but no volatile sulfur compounds in fresh roe.     

Effect of High Pressure Processing on the Quality and Endogenous Enzyme Activities of Grass Carp (Ctenopharyngodon idellus) Fillets Stored at 4ºC

ABSTRACT

This study assessed effects of high pressure processing on physicochemical quality and endogenous enzyme activities of grass carp fillets stored at 4 ºC for 21-day storage. Fresh fillets were vacuum-packed and subjected to high pressure processing (0.1, 200, 300, 400, 500, and 600 MPa at room temperature for 15 min). Results showed that high pressure processing significantly delayed microbial growth, and reduced total volatile basic nitrogen (TVB-N) and thiobarbituric acid reactive substances (TBARS) levels of grass carp fillets, especially for the 600 MPa group. On the 21st day, the corresponding increases of 6%, 35%, 45%, 43%, and 53% in hardness were observed for 200 MPa, 300 MPa, 400 MPa, 500 MPa, and 600 MPa samples compared with control samples, respectively. In addition, enzyme activities in different groups decreased during storage. Among them, calpain, and myofibril-bound serine proteinases (MBSP) activities were immediately reduced after high pressure treatments, while the activities of collagenase, cathepsin B, and cathepsin D were significantly (P < 0.05) inhibited when the pressure exceeded 400 MPa. However, the pressure treatments activated cathepsin L initially, and then the activity gradually decreased in treated samples. Generally, high pressure processing reduced activities of most of the endogenous enzymes and improved the quality and extended the shelf life by at least 4 ~ 6 days of refrigerated grass carp fillets.     

Effects of Natural and Artificial Colorants on Hot Smoked Garfish—Belone belone (Linnaeus, 1761)—Stored at 4 ± 1ºC

In this study, the effects of natural and artificial colorants on the shelf life of hot smoked garfish were investigated in terms of its chemical, microbiological, and sensory quality. Turmeric and Sunset Yellow FCF were used as the natural and artificial colorants, respectively. The amount of total volatile basic nitrogen (TVB-N) and thiobarbituric acid (TBA), counts of total mesophilic aerobic bacteria, total psychrophilic aerobic bacteria, total yeast and molds increased during the storage (p < 0.05). The results showed that turmeric and Sunset Yellow FCF had a significant effect on pH value and salt content of hot smoked garfish samples during storage (p < 0.05). According to the sensory analysis results, the shelf life of hot smoked garfish stored at 4 ± 1ºC was determined as 17 days.     

The Relationship Between Electric Impedance and Quality Parameters of Ungutted and Gutted Common Carp (Cyprinus carpio) Stored at 4°C

In order to understand the relationship between electric conductivity and quality parameters of common carp during storage, the electric impedances in the frequencies ranging from 1 to 20 kHz, total viable count (TVC), total volatile basic nitrogen (TVB-N), and K values of gutted and ungutted common carp were determined during 4°C storage. The result showed that the change ratio of electric impedance (Q value) of both gutted and ungutted common carp decreased with increasing storage time, while TVC, TVB-N, and K values increased gradually. There was a good correlation between Q values and TVC, TVB-N, and K values of gutted and ungutted common carp, and their correlation coefficients were 0.952, 0.965, 0.928, and 0.956, 0.975, and 0.938, respectively. This result demonstrated that Q value is valid to predict some quality parameters of common carp during 4°C storage.     

The Effect of Whey Protein Isolate Coating Enriched with Thyme Essential Oils on Trout Quality at Refrigerated Storage (4 ± 2°C)

ABSTRACT

The present study evaluated the effect of whey protein isolate (WPI) coating enriched with thyme essential oil (EO; 3, 5, and 7%, v/v) on whole trout chemical and microbial quality during refrigerated storage at 4 ± 2°C. As a result of this study, the addition of thyme essential oil to WPI coatings enhanced quality significantly better than that of the control and WPI coating without thyme essential oil during refrigerated storage, and this effect increased with an increase in the thyme EO concentration in WPI coating.     

Relationship between Lipid Oxidation,Protein Function Properties,and Freshness Changes of Salt-Treated Blunt-Snout Bream (Megalobrama amblycephala) Fillets Stored at 4°C

The aim of this study was to investigate the relationship between lipid oxidation, protein function properties, and freshness changes of blunt-snout bream (Megalobrama amblycephala) fillets treated with 2% and 4% salt during storage at 4°C. Salting with 2% and 4% salt could delay quality deterioration and protein denaturation, thus improving sensory attributes to some extent. But, 4% salt promoted lipid oxidation of blunt-snout bream fillets. There is a significant correlation (p < 0.05) between freshness indexes and lipid oxidation or protein function properties (total SH content, Ca²⁺-ATPase activity). Salting with 2% salt is an ideal treatment to control the quality of blunt-snout bream fillets stored at 4°C.     

Effect of Chitosan and Garlic Essential Oil on Microbiological and Biochemical Changes that Affect Quality in Grass Carp (Ctenopharyngodon idellus) Fillets During Storage at 4°C

Solutions of chitosan (2%, w/v), garlic essential oil (5%, v/v), and their combination (2%, w/v chitosan +5%, v/v garlic essential oil) were applied to the surface of grass carp fillets. Subsequently, sensory, microbiological analyses (total viable count (TVC), Pseudomonas spp., Aeromonas spp., and H₂S-producing bacteria), and physicochemical changes (total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substances (TBARS), and centrifugation loss) of grass carp fillets were evaluated over a 16-day storage at 4 ± 1°C. The treated samples resulted in significantly (p < 0.05) higher overall acceptance scores than the control from day 8. The TVC of grass carp fillets was reduced from the initial level (4.0 log CFU/g) to 2–3 log CFU/g when the fillets were treated with either garlic essential oil or chitosan solution. After 4 days of storage, the Pseudomonas spp. counts in the chitosan-treated samples were significantly lower (p < 0.05) than the counts in control and samples treated with garlic essential oil. A lag phase of 6 days for the counts of H₂S-producing bacteria of fish fillets that were treated with chitosan or the combination solution was observed. The combination of chitosan with garlic essential oil did not show synergistic effects, although it displayed a higher degree of antimicrobial efficacy with respect to the spoiled bacteria. However, the combination of chitosan with garlic essential oil was the most effective at inhibiting the formation of TVB-N. Samples that were treated with garlic essential oil displayed the highest TBARS levels on days 4 and 6 (p < 0.05).     

Quality Changes and Shelf Life of Cultured and Wild Hot-Smoked Mediterranean Horse Mackerel (Trachurus mediterraneus) at Refrigerated (4 ± 1°C) Conditions

ABSTRACT

Mariculturing of horse mackerel is not known in the world. Additionally, limited studies exist on quality changes of smoked horse mackerel at refrigerated temperatures. Therefore, in this study, between 1+ and 2-year-old wild and cultured horse mackerels were hot smoked and stored at refrigerated conditions. Chemical, microbiological, and sensory analyses were performed weekly to investigate quality changes and to determine the shelf stability of the products. The results of thiobarbituric acid, trimethylamine, and total bacteria counts were obtained within the acceptable levels. Although the counts of histamine-forming bacteria increased significantly (p < 0.05) during storage, histamine values were well below the permitted limits set by Food and Drug Administration and European Union (EU). Sensory results showed that both storage groups had 3 weeks of shelf life. Total volatile basic nitrogen values supported sensory results. Therefore, the results indicate that culturing of horse mackerel did not alter the quality during storage at 4 ± 1°C.     

Relationship Between Water Migration and Quality Changes of Yellowfin Tuna (Thunnus albacares) During Storage at 0°C and 4°C by LF-NMR

This study investigated postmortem changes of yellowfin tuna (Thunnus albacares) and water migration upon storage at 0°C and 4°C as determined by low-field nuclear magnetic resonance (LF-NMR ¹H). It clearly showed that with increasing storage time, sensory scores and physical evaluations (hardness, chewiness), proton density of the water, and moisture content decreased, while total volatile basic nitrogen (TVB-N), K value, aerobic plate counts (APCs), and psychrotrophic bacterial counts increased. The results of LF-NMR showed that T₂₁ (trapped water) had extremely significant correlations with sensory evaluation, texture profile analysis, TVB-N, K value, APC, and psychrotrophic bacteria (p < 0.01) and established multiple linear regression. It was concluded that the LF-NMR was an important technique to evaluate storage time and temperature of yellowfin tuna’s quality in terms of water migration during low-temperature storage.     

The Effect of Prior Frozen Storage (−20°C) on the Quality of Oven-Baked Sardines (Sardina pilchardus)

ABSTRACT

The effect of frozen storage for 3, 30, 60, 90, and 120 days on the quality of sardines baked for 15, 30, and 45 min was studied. The combination of frozen storage with the baking time in linear reduction of yield and moisture led to less juicy products, as well as significant changes in proteins and lipids. A linear increase of C16:0 followed by a linear reduction of C22:6ω-3 was detected due to frozen storage, indicating lipid oxidation. This was also confirmed by the C22:6ω-3/C16:0 and C20:5ω-3/ C16:0 ratios, which were reduced by 36.8 and 32.7%, respectively. The fatty acid profiles of sardine samples were not significantly altered due to oven-baking. A gradual reduction of eicosapentaenoic acid + docosahexaenoic acid (EPA + DHA) of the baked products was observed mainly due to frozen storage. Cholesterol and squalene content increased with increasing the time of baking. A gradual decrease of cholesterol and squalene was observed due to frozen storage.     

Effect of Thermal Microbial Inactivation and Washing on Quality Properties of Fish Sausage During Cold Storage (4°C)

The effect of microbial inactivation and washing process on physicochemical and sensory quality of pasteurized fish sausage during cold storage (4°C) was evaluated. Mince was obtained after the grinding; washed mince (WM) was obtained by single washing of mince; and surimi was obtained after three washing and dewatering cycles. Texture profile analysis results demonstrated that textural characteristics of pasteurized fish sausages remain stable during storage period (p > 0.05). Color analysis showed that Hunter L* had an increasing trend, and a* and b* had a decreasing trend over time (p < 0.05). Thus, it is possible to inactivate all microorganisms in pasteurized fish sausage without any undesirable effect on physicochemical and sensory quality.     

Inhibition of Melanosis,Microbial and Quality Changes of White Shrimp (Penaues vannameii) via Effect of Key Lime Juice and Vacuum Packaging at 2 ± 1ºC

This study aimed to investigate the effects of key lime juice (KL) in combination with vacuum packaging (VP) or air storage (SB) on the quality changes of white shrimp stored at 2 ± 1ºC. The quality was assessed using microbiological analysis, color measurement, pH, and total volatile base nitrogen (TVBN). Treatment with KL exhibited inhibitory activity on the growth of spoilage microflora. KL in combination with VP revealed a lower bacterial count in the range of 4.37–4.91 log CFU gˉ¹ on day 12 of storage as compared to other treatments. VP + KL and VP samples could inhibit melanosis. In addition, lower TVBN content was obtained in VP + KL (5.33 mg N/100 g), followed by VP (6.03 mg N/100 g) samples on day 12 of storage (p < 0.05). VP in combination with KL had the lowest loss of quality changes for the white shrimp. Therefore, VP + KL could be used as an alternative preservative method to extend the shelf life for white shrimp.     

High Drift Rate Effects of Propanil and Basis Gold on the Plankton Communities and Water Quality of a Prestocking Sunshine Bass,Morone chrysops × M. saxatilis,Fry Pond

ABSTRACT

Mesocosm-testing of aerially applied herbicides propanil and Basis Gold (86.8% atrazine) and indicated high drift rates (10–20% of field rates) resulted in adverse impacts on aquaculture production-pond phytoplankton, zooplankton, and critical water-quality variables. Effects on fry pond phytoplankton, zooplankton, and water quality from these herbicides were evaluated at 30% of field application rates, equal to the worst-case scenario from drift to these smaller ponds with consequent higher concentrations. The study was conducted in 12 outdoor pool mesocosms of 500 L volume, filled with pond water from an adjacent 0.1 ha pond fertilized and prepared as recommended for sunshine bass, Morone chrysops × M. saxatilis, fry stocking. Plankton and water quality samples were taken just prior to herbicide application (day 0) and on days 1,2,3,4-zooplankton only, and on day 7 after application. Field application rates for Basis Gold and propanil were 0.8 kg active ingredient and 1.80 kg/ha, respectively. Significant changes from control treatment values were found for several parameters in both herbicide treatments. Following application on June 20, net primary productivity was significantly depressed on day 1 in the propanil treatments, but increased on days 2 and 3. Morning dissolved oxygen (DO) was lower on days 1–3, but not to critical levels. Also, in the presence of propanil, pH and consequently UIA were lower from day 1 to 3. Basis Gold reduced morning DO on days 2 and 3, but not net primary productivity. Nitrite-N, however, was significantly higher on day 1. Phytoplankton total numbers, and the cyanobacterium Chroococcus sp. which dominated, were reduced by propanil on days 1 -3; and similarly affected by Basis Gold on days 2 and 3. Numbers of green algae, Scenedesmus sp. and Coelastrum sp., and diatoms were, however, stimulated by propanil and diatoms by Basis Gold. Zooplankton were little affected by either herbicide. Thus, high levels of drift from propanil and Basis Gold should not result in negative impacts on fry production.     

Study of Chemical Composition and Efficacy of Different Extracts of Iranian Propolis on the Microbiological and Sensory Parameters of Minced Cyprinus carpio Meat at 4°C Storage

This study has evaluated the effects of different concentrations of the water and ethanolic extracts of Iranian propolis (WEP and EEP) on the microbiological and sensory parameters of minced common carp meat that was stored at 4°C for 9 days. The chemical compounds of the extracts were identified by gas chromatography–mass spectroscopy (GC-MS) analysis. The results revealed that WEP and EEP extracts were efficient against the spoilage microorganisms, including total plate counts (TPCs), psychrotrophic populations (PTCs), lactic acid bacteria (LAB), and even Staphylococcus aureus. There was a significant difference in the bacteria growth between samples treated with WEP or EEP and the control sample during storage. Inhibitory effects were, respectively, 7% EEP > 5% EEP > 3% EEP > 7% WEP > 5% WEP > 3% WEP. In all treatments, PTC counts were higher than 7 log CFU/g after 6 days as well as TPC, LAB, and S. aureus populations after 9 days. Overall, the results show that EEP and WEP have good antimicrobial activity due to high phenolic and flavonoid compounds, including caffeic acid, tectochrysin, aceacetin, chrysin, pinostrobin, pinobanksin-3-acetate, galangin-3-methyl ester, and pinocembrin chalcone. Sensory evaluation shows very slight improvement in sensory properties (color, odor, texture, and overall acceptability) of the treated samples with the different extracts of Iranian propolis.     

Effects of Cottonseed and Alfalfa Meals as Fertilizers on Production of Palmetto Bass (Morone saxatilis × M. chrysops) Fingerlings in Plastic-Lined Ponds

Effects of cottonseed meal versus alfalfa meal fertilization on water quality, zooplankton density, and production of phase I palmetto bass, Morone saxatilis × M. chrysops, were compared in plastic-lined ponds. Cottonseed meal promoted better (P < 0.05) water quality, timing of high zooplankton density development, and growth and yield of palmetto bass. Cost of cottonseed meal toward fish production was $0.75/kg of fish, while that of alfalfa meal was $1.74/kg of fish.     

Effect of Chitosan-Gelatin Composite and Bi-Layer Coating Combined with Pomegranate Peel Extract on Quality Properties of Belanger’s Croaker (Johnius Belangerii) Stored in Refrigerator

The aim of this study was to evaluate the effects of chitosan-gelatin coating with two different methods (composite and bi-layer) in combination with pomegranate peel extract (PPE) on the microbiological (mesophilic bacteria, psychrotrophic bacteria, and Enterobacteriaceae) and chemical (total volatile bases-nitrogen (TVB-N), pH, thiobarbituric acid (TBA), and free fatty acid (FFA)) properties of Belanger’s croaker (Johnius belangerii) fillets during refrigerated storage (4 ± 1°C). In this study, composite coating (CC), bilayer coating (BC), CC+PPE, and BC+PPE led to 6.88, 7.00, 6.52, and 6.32 log₁₀ CFU/g reduction in mesophilic bacteria, 6.67, 7.02, 5.35, and 4.21 log₁₀ CFU/g in PTC and 2.99, 2.71, 2.37, and 2.41 log₁₀ CFU/g, compared with control sample for 16 days storage time, respectively. Chitosan-gelatin coating enriched with PPE has retarding effects on spoilage of fish samples, thus extending the shelf life during refrigerated storage. The quality characteristics of croaker treated with chitosan-gelatin coating combined with PPE were better than those treated by chitosan-gelatin coating or PPE alone during the storage, exhibiting that there is a synergistic effect between chitosan-gelatin coating and PPE. The bi-layer coating was better than one composite coating in combination with PPE in reducing lipid oxidation of fillets.     

Quality Indices of Cooked Southern King Crab (Lithodes santolla Molina, 1782) Meat During Storage at 0 and −20°C

ABSTRACT

The aim of this work was to determine the changes in quality of cooked southern king crab (Lithodes santolla) meat during storage at 0°C for 5 and 10 days and ?20°C for 10, 30, 60, and 90 days. Chemical indices varied from the initial to the final storage time in refrigerated and frozen samples as follows: TVB-N, 15.8–29.2 and 15.8–23.2 mg/100 g; TMA, 0.0–8.3 and 0.0–1.2 mg/100 g; formaldehyde, 0.5–8.6 and 0.5–3.7 mg/kg; indole, 3.3–20.7 and 3.3–6.6 µg/100 g; lactic acid, 16.4–39.1 and 16.4–16.6 mg/100 g; and P ratio, 0–28.4 and 0–5.2%, respectively. The total nucleotide content rendered 6.77 µmol/g, with adenosine monophosphate (AMP) the main component. The nucleotide indices varied in refrigerated and frozen samples as follows: K, 7.37–27.5 and 7.37–10.3%; Ki, 58.3–86.5 and 58.3–82.7%; H, 30.2–54.9 and 30.2–38.0%; G, 19.4–57.8 and 19.4–15.8%; P, 17.2–42.3 and 17.2–14.7%; and Fr, 41.6–13.4 and 41.6–17.3%, respectively. Biogenic amines found at both storage temperatures were spermine, spermidine, tyramine, and agmatine. Spermine may be considered as a potential freshness index for refrigerated samples and spermidine for frozen storage. The tyramine level should be monitored. During the storage period tested, none of the chemical indices studied exceeded the legal limits.