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1.
The effects of chemical treatments on color change of yellow discolored catfish fillets during both refrigerated and frozen storage were investigated in this work. For the refrigerated storage (4°C), the effects of concentration of sodium bisulfite on reducing the yellow discoloration were studied. Compared to the untreated fillets, sodium bisulfite treatments with concentrations ranging from 0.75 to 1.50% could evidently reduce the yellowness and increase the brightness of the fillets after 7 days refrigerated storage. Since no notable improvement was observed when increasing the concentration of sodium bisulfite beyond 1.0%, the concentration range of 0.75–1.0% is recommended in this work. For the frozen storage (?20°C), the effects of sodium bisulfite and sodium bicarbonate treatments were investigated. Both 1.0% sodium bisulfite and 0.5% sodium bicarbonate treatments made the fillets slightly less yellow and less red. The 1.0% sodium bisulfite treatment also made the fillets slightly brighter. These effects were similar to those under refrigerated storage, but the changes in color were much less. The color changes were related to the degradation of carotenoids in the discolored fillets. The low temperature of frozen storage significantly limited the reaction rates and suppressed the color change processes.  相似文献   

2.
This study was designed to determine if treatment with low dose X‐ray irradiation changes microbial quality (microbial load), safety (Listeria monocytogenes incidence), and sensory characteristics (aroma, appearance, and texture) of fresh aquacultured Channel catfish (Ictalurus punctatus) fillets during refrigerated storage. Fillets were treated to 0, 0.5, 1.0, and 1.5 kGy using an X‐ray irradiator and stored at 3°C for 17 days. Fillet aerobic plate count (APC), psychrotrophic plate count (PPC), total coliform count (TCC), and L. monocytogenes incidence were measured every 4 days during storage. A Difference-From-Control test was used to measure aroma, appearance, and texture. Fillet microbial counts were significantly different (p < 0.05) with time, irradiation dose, and the interaction of these two treatments. As expected, APC, PPC, and TCC increased as storage time increased. Overall L. monocytogenes incidence was 40%, 27%, 0%, and 7% at 0, 0.5, 1.0, and 1.5 kGy, respectively. Aroma of irradiated and non‐irradiated catfish fillets was significantly different, with greater aroma differences recorded as storage time increased due to progressional spoilage of the untreated controls. However, there were no significant aroma differences noted among the different irradiation doses. Neither appearance nor texture was significantly different between any treatments throughout testing. This study indicated that exposure to low dose X-ray irradiation improved the microbial quality and safety of fresh catfish fillets without affecting sensory acceptability at time of purchase.  相似文献   

3.
Catfish fillets with yellow coloration have become a prevalent problem for the catfish industry. This problem is due to the unacceptability in the market because the shift in fillet color is considered of lower quality by the consumers. To help the catfish industry better understand the yellow coloration of catfish fillet, a digital photography measurement method was developed to evaluate the yellowness. Sixty catfish fillets with a range of degrees of visible yellowness were taken directly from the processing line. The fillets were photographed in a light box with a digital camera. The photos were calibrated with the X-Rite ColorChecker standardized color target. CIELAB readings of the fillet photos were recorded, and the b* value was used to indicate the yellowness of catfish fillets. The xanthophyll levels of fillets were analyzed with high performance liquid chromatography. The actual xanthophyll level in catfish fillet was calculated as the sum of lutein, zeaxanthin, and alloxanthin. A linear correlation was found between the LAB b* values and xanthophyll levels of the 60 catfish fillets.  相似文献   

4.
A study was conducted to determine the clearance time of yellow pigments lutein and zeaxanthin in channel catfish at various temperatures. Fish of initial weight of 13.4 g were stocked into flow‐through aquaria and fed daily with a pigment‐enhanced diet for 11 wk when yellow color became visible in the flesh. All fish were then transferred into tanks in three recirculating systems that were assigned one of the three temperatures (10, 20, and 30 C). During the pigment clearance period, fish were fed a control diet without added pigments daily to satiation for 12 wk. Every 4 wk, fish from three randomly chosen tanks per temperature were euthanized and fillets were analyzed for yellow color intensity (Commission Internationale de I’Eclairage [CIE] b*) and lutein and zeaxanthin concentrations. The b* values of fillets of fish reared at 20 and 30 C decreased linearly as time progressed. There was no significant linear regression of b* value against time for fish raised at 10 C. The rate of pigment clearance was similar for fish reared at 20 and 30 C. Results demonstrate that about 8 wk were needed for catfish to “purge” most of yellow pigment at warm temperatures (20 and 30 C). A longer period of time (> 12 wk) was required at 10 C.  相似文献   

5.
Listeria monocytogenes presents a serious threat to consumer safety because it is resistant to various food storage techniques, including reduced or modified atmosphere packaging, refrigerated storage, and increased salt concentration. Edible coatings incorporated with natural antimicrobials have been suggested to control pathogenic and spoilage bacteria on a variety of meat products. In this study, edible zein‐based coatings incorporated with nisin and lemongrass essential oil (LGEO; 8%) were evaluated for antibacterial action against L. monocytogenes and spoilage organisms on fresh, cultured hybrid striped bass, Morone saxatilis × Morone chrysops, under two storage conditions (refrigerated or frozen) and two packaging types (polyvinyl chloride [PVC] and vacuum packing) over time. Corn‐zein‐based edible coatings were found to be an effective carrier for nisin and LGEO. Fillets coated with nisin showed the largest decrease in L. monocytogenes cell counts in both PVC and vacuum‐packaged samples in both refrigerated and frozen product, while fillets coated with LGEO showed intermediate inhibition of L. monocytogenes cell counts, with the strongest LGEO antibacterial effect being found in frozen product regardless of packaging. Both nisin and LGEO treatments were most effective in PVC‐packaged fillets compared to vacuum‐packaged fillets, but the difference in bacterial loads between packaging methods was minor. Bacterial loads on refrigerated product tended to increase slightly after 5‐d storage regardless of coating treatment or packaging, whereas bacterial loads on frozen product remained stable or decreased with time up to 60 d regardless of coating treatment or packaging. Data from the present study indicate that application of edible coatings incorporated with essential oils not only promotes food product safety but also may satisfy the preferences of consumers.  相似文献   

6.
The aim of the present study was to determine the effects of natural antioxidant extract isolated from the shells of giant red shrimp (Aristaeomorpha foliacea) on the changes in fatty acid profile of anchovy (Engraulis encrasicolus) during refrigerated storage (2.7°C). Total antioxidant activity of shell extract was determined as 45.84%, total phenolic compound as 17.87 mg/100 g shell, and total carotenoid content in shell as 20.31 mg/100 g shell. Total saturated fatty acid (SFA), monounsaturated fatty acid (MUFA), and polyunsaturated fatty acid (PUFA) contents in the control group and the group with 0.1% shell extract addition were found to be affected by the duration of storage (p < 0.05). A percentage increase was determined in MUFA content, while decreases were observed in PUFA content. No statistically significant change was detected in SFA, MUFA, and PUFA contents of groups with added butylated hydroxytoluene (BHT) and 0.5% of shell extract (p > 0.05). It was concluded that the extract isolated from shrimp shells could be used during the cold storage of fish fillets instead of synthetic antioxidants.  相似文献   

7.
Consumer uncertainty of irradiated food products has slowed implementation of food irradiation, even though it has been proven as a safe and effective technology. For acceptance, irradiated products should not be distinguishable from alternatively processed products. The present research was designed to determine if X-ray irradiation treatment results in changes in selected quality parameters (color, texture, and oxidation) of fresh aquacultured channel catfish fillets. Fillets (Ictalurus punctatus) were treated to 0, 0.5, 1.0, and 1.5 kGy using an X-ray irradiator and stored at 3°C for 17 days. Periodically during storage, samples were removed and instrumentally measured for color, texture, and oxidation (thiobarbituric acid reactive substances). Color, texture, and oxidation did not change (p > 0.05) over time or with irradiation dose. Results indicated that low-dose X-ray treated raw catfish fillets were not distinguishable from untreated controls.  相似文献   

8.
Fillets of channel catfish, Ictalurus punctatus, from three geographic areas, fillets of hybrid catfish (♀ I. punctatus × ♂ blue catfish, Ictalurus furcatus) from one of the areas, water samples from the culture ponds, and feed samples were subjected to elemental analysis by inductive‐coupled plasma atomic emission spectrometry (ICP‐AES). The fillets were low in concentrations of several elements, and ICP‐AES could consistently detect only 11 elements. In addition, the composition of the fillets was not greatly influenced by water chemistry or feed composition. Nevertheless, both canonical discriminant analysis and K‐nearest‐neighbor analysis were reliable in separating the fillets to geographic area of origin and separating hybrid from channel catfish fillets based on elemental composition. Although this study suggests that multielement analysis and pattern recognition techniques have potential for validating the geographic origin of catfish fillets, much more work is needed to perfect the technique .  相似文献   

9.
Rainbow trout were pigmented with diets containing synthetic astaxanthin, canthaxanthin, or dried krill meal to 6 mg carotenoid/Kg (wwb) flesh. Vacuum packaged frozen fillets were held at -18°C, -28°C or -80°C for 90 d, 180 d, or 90 d, thawed, and refrozen for an additional 90 d. Tristimulus color (L*,a*,b*), carotenoid concentration, fatty acid composition and TBARS were measured for raw and cooked fillets. We observed no change in pigment content or in a* values after 180 d frozen storage or following a thaw/refreeze cycle compared to fresh fish, even though a higher a* values were seen in fillets from fish fed synthetic astaxanthin or canthaxanthin after 90 d frozen storage suggesting that care should be used when interpreting tristimulus color values for grading programs.  相似文献   

10.
This study was conducted to determine effects of dietary Fe levels on growth performance, hepatic lipid metabolism and antioxidant response for juvenile yellow catfish Pelteobagrus fulvidraco. Yellow catfish were fed six isonitrogenous and isolipidic diets containing Fe levels of 16.20, 34.80, 54.50, 76.44, 100.42 and 118.25 mg/kg for 8 weeks. Weight gain (WG) and specific growth rate (SGR) increased with dietary Fe levels from 16.20 to 54.50 mg/kg diet and then plateaued over the level. Feed conversion rate (FCR) was highest and protein efficiency rate (PER) was lowest for fish fed the lowest Fe levels of diet. Fe contents in whole body and liver increased with increasing dietary Fe levels. Hepatic lipid content was lowest, but mRNA levels of carnitine palmitoyltransferase (CPT‐1) and peroxisome proliferator‐activated receptor α (PPARα) were highest for fish fed 54.50 mg Fe/kg diet. Fish fed adequate dietary Fe levels reduced hepatic malondialdehyde (MDA) level and increased activities of antioxidant enzymes Superoxide dismutase (SOD), Catalase (CAT) and GS. Based on the broken‐line regression analysis of WG against dietary Fe levels, optimal dietary Fe requirement for yellow catfish was 55.73 mg Fe/kg diets. Fe‐induced changes in MDA levels and antioxidant enzymatic activities paralleled with the change in hepatic lipid content, suggesting the potential relationship between oxidative stress and hepatic lipid accumulation in yellow catfish.  相似文献   

11.
Yellow catfish Pelteobagrus fulvidraco (Richardson) is a commercially important fish generally distributed in Southeast Asian countries. The well‐known aetiological agent of enteric septicaemia of catfish, Edwardsiella ictaluri, was isolated from diseased yellow catfish P. fulvidraco (Richardson) reared at two commercial fisheries in China. The economic losses due to the high mortalities (about 50%) caused by this bacterium have been increasing annually. The affected fish presented two different, typical symptoms: pale gills, slight exophthalmia and a ‘hole in the head’, and haemorrhage on the opercula, in the skin under the jaw, creating a ‘hole under the jaw’. These diseases were found frequently in cultured yellow catfish throughout China. The isolates from both outbreaks were all Gram negative, facultatively anaerobic and short rod. Morphological and biochemical tests and phylogenetic analysis based on the 16S rDNA sequences all strongly indicated that these yellow catfish isolates were highly identical to the known E. ictaluri. In addition, the isolates possessed the typical plasmid profile of E. ictaluri. Experimental infection assays were conducted and pathogenicity (by an intraperitoneal injection) was demonstrated in yellow catfish and channel catfish Ictalurus punctatus. The results showed that yellow catfish isolates were quite conservative phenotypically and genetically, and were able to cause two different, typical symptoms in this fish under unknown conditions and mechanism.  相似文献   

12.
The effect of gamma irradiation (0, 1.8, and 3.3 kGy) on the microbiological, chemical, and color characteristics of marinated (7% acetic acid and 10% NaCl) and vacuum-packed anchovy fillets was analyzed during 20 months of refrigerated storage (4 ± 1°C). Acidity, pH, water activity (aw), total volatile basic nitrogen (TVBN), lipid oxidation, and color parameters were determined. Mesophilic and psychrotrophic bacteria, sulphite-reducing clostridia, total and fecal coliforms, Staphylococcus spp., yeasts, and molds were investigated. Gamma irradiation reduced the initial mesophilic bacterial counts and inhibited mesophils growth during 20 months. As a result, the production of TVBN during storage was lower in irradiated samples than in control. Also, lipid oxidation was lower in irradiated samples than in nonirradiated. The color of anchovy fillets was not affected by the irradiation treatment. Even if nonirradiated anchovy fillets presented a high stability in comparison with the traditional product (in flasks with vegetable oil and spices), gamma irradiation improved the microbiological and chemical quality of anchovy fillet marinades without inducing changes on its characteristic color for 20 months.  相似文献   

13.
To investigate the biopreservative effectiveness of pediocin ACCEL on refrigerated seafoods, fresh fish fillets were immersed in various concentrations of pediocin ACCEL and then stored at either 4° or 0°C. Samples treated with nisin were used as a positive control. The aerobic plate counts (APC) of samples with bacteriocins were <2.0 log10cfu/g (log cfu/g) after 2 days storage at 0°C, except that with 1500 IU/mL of pediocin ACCEL. The APC of samples with nisin were >2.0 log cfu/g after 2 days storage, while those with pediocin ACCEL occurred after 1 day storage at 4°C. In refrigerated seafoods, pediocin ACCEL and nisin suppressed the growth of inoculated Listeria monocytogenes during 2- and 1-week storage at 4°C, respectively. Compared with nisin, the pediocin ACCEL was considered to be more effective on the suppression of L. monocytogenes growth in refrigerated seafoods during 2-week storage at 4°C.  相似文献   

14.
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15.
The deceptive marketing of imported basa, Pangasius bocourti (Sauvage), fillets as catfish has resulted in serious economic losses to the channel catfish, Ictalurus punctatus (Rafinesque), industry in the US. The similar appearance of channel catfish and basa fillets created a need for a rapid method to differentiate uncooked, cooked and/or marinated channel catfish fillets from basa fillets and other fish products. A monoclonal antibody (MAb) specific for a 36.8 kDa channel catfish fillet protein was produced and characterized by an indirect enzyme‐linked immunoabsorbent assay (ELISA) and Western blotting. This MAb was used to develop an indirect ELISA specific for a fillet protein unique to fish of the genus Ictalurus. Using this ELISA, 100% of raw and cooked channel catfish fillets were correctly identified and differentiated from other fish in a single‐blind study. These results show that the indirect ELISA using MAbs specific for unique Ictalurus sp. fillet proteins is a rapid and sensitive method for the identification of raw and cooked catfish fillets.  相似文献   

16.
Channel catfish, Ictalurus punctatus, 88.4 ± 2.6 g/fish, were fed a basal diet amended with 4% of three processed menhaden, Brevoortia tyrannus, oils. These were compared with basal diets amended with 4% corn oil or 4% canola oil. Three replicate aquaria of nine fish each were fed assigned diets twice daily. At 6 wk, fish were group weighed, fillets were collected for sensory evaluation, fatty acid analysis by gas chromatography (GC). In a second study, catfish, 118.8 ± 3.2 g/fish, were stocked into fifteen 0.04‐ha earthen ponds and fed once daily for 16 wk one of four diets containing 2 or 4% of either catfish offal oil or refined (RF) menhaden oil. At harvest, fillets were saved for sensory evaluation and fatty acid analysis. Results showed no significant (P > 0.05) differences among treatments for aquarium study and pond study variables such as weight gain, fillet proximate analysis, or pond production. GC analysis showed that levels of omega‐3 (n‐3) highly unsaturated fatty acids (HUFA) in fillet lipid were significantly (P < 0.05) elevated for fish fed menhaden oil diets. Sensory evaluation revealed that fillets from fish fed RF menhaden oil had satisfactory flavor and could be a source of n‐3 HUFA for humans.  相似文献   

17.
Salmonella and Listeria monocytogenes (LM) are occasional contaminants on raw fish. Catfish fillets were artificially contaminated with LM and Salmonella, dipped in a 1.5 % (30 min) trisodium phosphate solution (TSP), and cryogenically frozen. After 3 months frozen storage, Salmonella (2 log), but not LM, was inactivated on the fillets treated with the dip. This indicates that TSP dip followed by cryogenic freezing can be used to control Salmonella, but not LM, on catfish fillets.  相似文献   

18.
A study was conducted to evaluate effects of various carotenoids on skin and fillet coloration and fillet carotenoid concentration in channel catfish, Ictalurus punctatus. For 12 wk, juvenile catfish were fed one of six experimental diets containing no supplemental carotenoid or 100 mg/kg of one of following carotenoid additions: β‐carotene (BCA), lutein (LUT), zeaxanthin (ZEA), canthaxanthin (CAN), and astaxanthin (AST). Visual yellow color intensity score was highest for fish fed LUT, followed by ZEA, AST, and CAN, and lowest for fish fed basal and BCA diets. Skin and tissue Commission Internationale de I’Eclairage yellowness value was the highest in fish fed LUT, followed by fish fed ZEA, AST, and CAN, and lowest for fish fed basal and BCA diets. Fish accumulated the supplemental carotenoids in muscle tissues, but concentrations of different carotenoids in the tissue varied greatly. Approximately 30% of the LUT added was converted to echineone; no conversion was observed among other supplemental carotenoids. Results from the present study indicate that channel catfish can accumulate yellow pigments LUT and ZEA and red or pink pigments CAN and AST in the flesh, resulting in yellow coloration. The yellow pigment BCA does not appear to deposit in skin or flesh at levels sufficient to alter the coloration.  相似文献   

19.
The objective of this study was to determine the effects of various agglomerated phosphate blends on the quality of vacuum-tumbled catfish fillets. Catfish fillets were tumbled with a brine solution at 15% over initial, raw weight prior to tray-packing and storage at 4°C for 10 days. Fillets were evaluated for protein exudate, tumbling yield, color, pH, cooking loss, tenderness, purge loss, and shelf life. A specific blend of agglomerated sodium phosphates (AGSP) that contains mono-, tri-, and polyphosphates had significantly less protein (p < 0.05) exudate and significantly higher pH (p < 0.05) than other treatments. All phosphate treatments significantly increased (p < 0.05) tenderness and significantly decreased (p < 0.05) purge loss, but agglomerated phosphate blends significantly decreased (p < 0.05) cooking loss and yellowness. Psychrotrophic plate counts for all phosphate treatments were similar to the control at each storage time. All phosphate treatments improved the yield and quality of catfish fillets, but the use of AGSP may optimize quality attributes.  相似文献   

20.
The preservative effect of refrigerated and vacuum-packed sea bass (Dicentrarchus labrax) fillets inoculated with four mixtures of lactic acid bacteria (LAB) (Lactococcus lactis, Lactobacillus plantarum, and Carnobacterium piscicola) and incorporated with citrus essential oil (CEO) was evaluated on the basis of microbiological and biochemical analysis.

Initially, sea bass fillets showed high nutritional quality. During refrigerated storage, lipid contents did not show a significant decrease in any fish fillets; meanwhile, important proteolysis was observed in untreated control. In addition, results indicated that both CEO and LAB strains exhibited antimicrobial activity against spoilage, pathogenic, and fungi flora. Moreover, the total volatile bases (TVB-N) values were higher in control fillets, and the lowest TVB-N values were observed in Control CEO and C3 + CEO (30.47 ± 0.00 and 32.29 ± 1.12 mg TVB-N/100 g, respectively). Also, the levels of biogenic amines increased in all fillets without exceeding the upper limit of acceptability except for untreated control (sum of about 1396.63 ppm). Furthermore, this combined treatment ameliorated the muscle liquid-holding capacity, which improves technological properties.

Overall, this treatment may open new promising opportunities for the biopreservation of fish products by enhancing the period of storage of refrigerated and vacuum-packed sea bass fillets.  相似文献   


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