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1.
The effect of Ultraviolet radiation type C (UV-C) radiation (0.100 ± 0.010 J/cm2) on shelf life of Arapaima gigas fillets stored at 4 ± 1°C for 18 days was investigated. The samples were analyzed for total aerobic mesophilic bacteria (TAMB) counts; total aerobic psychrotrophic bacteria (TAPB) counts; Enterobacteriaceae; purge loss; pH; lipid oxidation; total volatile bases (TVB-N); ammonia; biogenic amines (BAs); and L*, a*, and b* values. UV-C radiation increased (< 0.05) the generation time of all bacterial groups evaluated, increasing the shelf life by 2 days. UV-C-treated fillets showed lower (< 0.05) L* values, purge loss, pH, TVB-N, ammonia, and BAs levels than their control counterparts throughout the storage period. Moreover, UV-C treatment did not result (P > 0.05) in detrimental effects on lipid oxidation or a* and b* values. UV-C at 0.100 J/cm2 demonstrated a good potential for use in A. gigas fillets and, therefore, it could be applied at industrial scale.  相似文献   

2.
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.  相似文献   

3.
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.  相似文献   

4.
The aim of the present study was to assess the physicochemical and microbiological changes during sun drying of salted wolf herring (Chirocentrus dorab) and coastal trevally (Carangoides coeruleopinnatus). For that purpose, the pH value, moisture, sodium chloride (NaCl) content, total volatile base nitrogen (TVB-N), histamine, cadaverine, putrescine, tryptamine, tyramine, spermine, and spermidine, as well as total aerobic mesophilic count, amine forming bacteria, total coliforms, Staphylococcus spp., and Bacillus spp., were determined. The initial pH value was 6.4 and increased during the salt drying process to 6.9 in both cases. The initial moisture, salt, and TVB-N levels of C. dorab and C. coeruleopinnatus were 64.3 and 60.3%, 2.55 and 2.70%, and 22.8 and 16.2 mg/100 g, respectively. At the end of drying, moisture decreased to 31.3 and 35.6%, respectively; salt increased to 13.71 and 16.04%; and TVB-N increased to 35.9 and 33.13 mg/100 g, respectively. Regarding total aerobic mesophilic count, amine forming bacteria, total coliforms, Staphylococcus spp., and Bacillus spp., a statistically significant (P < 0.05) reduction of the population was observed in both cases. Regarding the biogenic amine forming bacteria, Morganella morganii and Klebsiella pneumoniae were isolated from C. dorab; Bacillus cereus, Staphylococcus xylosus, and Providencia rettgeri were isolated from C. coeruleopinnatus. During sun drying, the amount of histamine, cadaverine, putrescine, and tryptamine was reduced; spermine was detected in C. dorab only during the first day, whereas spermidine was not detected. This reduction may be attributed to the presence of biogenic amine decomposing bacteria. However, further research is necessary in order to verify in situ this capacity and exploit potential applications for fish and fishery products.  相似文献   

5.
Changes in the content of biogenic amines (BA; e.g., putrescine, tyramine, and histamine) and the mesophilic and psychrotrophic bacterial counts of tiger-tooth croaker (Otolithes ruber) were monitored during ice storage for 18 days. BA and bacterial loads gradually increased (p < 0.05) with storage time. On the first day of storage, no amines were detected, and no histamine was detected up to 6 days. The best linear regressions between BA and bacterial counts were found between putrescine and psychrotrophic bacteria. Furthermore, it was found that psychrotrophs were the dominant microorganisms during storage and showed significant (p < 0.05) differences with storage time. The initial concentration of putrescine was 1.27 μg g?1 and reached 18.8 μg g?1 when the psychrotrophic bacterial load was over 108 CFU g?1. The results suggest that the level of putrescine is a suitable indicator of freshness for O. ruber, and the shelf life of O. ruber stored in ice as determined by BA content and microbiological data was 10 days.  相似文献   

6.
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   


7.
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   

8.
Chitosan coating and plastic wrap coating were investigated for their effects on the quality of grass carp fillets stored at 4 ± 1ºC for a period of 20 days. The fillets were divided into groups of untreated (Control), wrapped with sterile preservative film (PE), and chitosan-treated (1, 2, and 2.5% w/v corresponding to CH1, CH2, and CH2.5, respectively). The final result demonstrated that chitosan coating has positive effects on the microbial inhibition of total volatile count (TVC), lactic acid bacteria (LAB), Enterobacteriaceae, Pseudomonas, H2S-producing bacteria (including Shewanella putrefaciens), and Staphylococcus. With regard to the results of biogenic amines (BAs), putrescine (PUT) and histamine (HIS) were the major amines, and their concentration was significantly (p < 0.05) higher in Control and PE than in chitosan-coated fillets at the end of storage. The final concentration in Control, PE, CH1, CH2, and CH2.5 was 143.7, 160.1, 83.0, 59.4, and 44.2 mg/kg for PUT and 228.0, 57.1, 4.1 3.2, and 2.9 for HIS, respectively. Chitosan coating was found to inhibit the increase of total volatile base nitrogen (TVB-N), microbial population, and total BAs and prolong the shelf life of grass carp fillets. However, sterile plastic wrap coating had little positive effect on maintaining the quality of grass carp fillets during refrigerated storage.  相似文献   

9.
The effect of spraying microbial transglutaminase (MTGase) at various levels (1, 4, 7, and 10 units/gram) on the quality of mackerel (Scomber scombrus) fillets was investigated during refrigerated storage. The results of pH and the total volatile base nitrogen (TVB-N) revealed that 7 µ/g MTGase treatment met the best results regarding fish quality. The oxidation was hindered by increasing MTGase concentration, and the lowest totox value was recorded in the fillets treated with 10 µ MTGase. The progress in the total free amino acids was suppressed with the addition of MTGase, and the most effective concentration was found to be 7 µ/g MTGase treatment. Moreover, this concentration was the most promising in inhibition of the total mesophilic aerobic bacteria, the total psychrophilic aerobic bacteria, coliform, and yeast-mold. Panelists preferred the samples treated with 7 µ/g MTGase in terms of odor, texture, and appearance. The addition of MTGase straightened the fish muscle and helped preserve its initial texture. It is important to use the proper concentration of MTGase instead of high concentrations.  相似文献   

10.
The aim of this study was to investigate the quality changes of pasteurized soup prepared from smoked trout trimmings during 8 months of refrigerated storage at 3°C. Thiobarbituric acid (TBA, mg malonaldehyde/kg), total volatile content (TVB-N, mg N/100 g), total aerobic mesophilic plate count, pH value, color measurement, and sensory evaluation were used to determine quality changes. After 8 months of storage, TBA values reached 0.83 ± 0.09 mg malonaldehyde/kg. Despite a marked increase in the TBA value at Month 8, the soup was still of acceptable quality. The TVB-N value was close to the European Commission limit on fresh fish at Month 4, and further increase was not significant (p > 0.05). Total aerobic mesophilic count reached a maximum value of 4.15 ± 0.23 log cfu/g at Month 2 with 3.20 ± 0.02 log cfu/g at Month 8. The soup had an overall acceptability score of 7.16 ± 0.68 (“like moderately” on a 1- to 9-point hedonic scale). Results suggest that smoked trout trimmings can be used to maximize the value of co-products by producing a ready-to-eat soup.  相似文献   

11.
ABSTRACT

In the present study, the effect of fish gelatin coating (FG; 4%, w/v) containing oregano (Origanum vulgare L.) essential oil (OEO; 1.2% w/v) on shelf-life extension of rainbow trout (Oncorhynchus mykiss) fillet stored under refrigerated storage (4 ± 1ºC) was investigated. The control and the treated fish samples were analyzed periodically for chemical (pH; total volatile basic nitrogen, TVB-N; peroxide value, PV; thiobarbituric acid, TBA) and microbiological (total viable count, TVC; psychrotrophic count) characteristics. The FG + OEO treatment produced significantly lower (p < 0.05) TVB-N values as compared to control and FG-coated samples after Day 6 and until the end of the storage period. The TBA values remained low and were found to fluctuate during storage. Results showed that TVC exceeded 6 log CFU g?1 on Day 8 of storage for control and FG-coated samples and Day 12 for samples coated with FG + OEO. The reduction of 1.05 and 0.83 log CFU g?1 of psychrotrophic counts was achieved by FG + OEO coating in trout fillet (p < 0.05) as compared with control and FG-coated samples, respectively. Therefore, the incorporation of OEO into FG coating may be a promising method of maintaining the storage quality of the rainbow trout fillet stored at refrigerated temperature.  相似文献   

12.
The microbiological quality of 18 commercially available in Spain ready-to-eat fish products containing Engraulidae was evaluated through application of the corresponding ISO procedures for total mesophilic aerobic microbial counts, detection and enumeration of enterobacteria, and detection of Staphylococcus spp. All isolates were identified to the species level using two different biochemical methods: the API® test and the Biolog® identification system. The most commonly occurring contaminants found were Enterobacteriaceae—such as Citrobacter freundii and other Citrobacter species, Enterobacter cloacae, Cronobacter sakazakii, Hafnia alvei, Pantoea, Proteus ssp., and Escherichia coli. The presence of such opportunistic pathogens and contaminant microflora was confirmed in 61% of the foods sampled.  相似文献   

13.
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 (< 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.  相似文献   

14.
为比较日本鲭和大黄鱼肌肉中微生物和代谢功能的变化及其与鱼肉腐败特性之间的关系,本研究检测了2种鱼在冷藏过程中的理化指标和菌落总数的变化,利用Illumina Miseq测序技术分析细菌群落变化,并利用皮尔森相关性分析检验微生物与鱼肉腐败及组胺产生相关性,结合功能预测分析细菌群落组成与代谢功能之间的关系。结果显示,冷藏期间日本鲭和大黄鱼的pH、挥发性盐基氮、组胺、菌落总数等均呈上升趋势,且日本鲭上升较快;冷藏末期2种鱼TVB-N值和组胺含量分别达到76.34、59.98和59.92、3.11 mg/100 g;日本鲭肌肉中细菌丰富度和多样性先增加后减少,大黄鱼则整体呈下降趋势;2种鱼肌肉中的优势腐败菌均为希瓦氏菌属;日本鲭体内与TVB-N产生相关的菌共12种,其中10种与组胺产生具有显著相关性;大黄鱼体内与TVB-N产生相关的菌共7种,但未检测出与组胺产生具有相关性的细菌;冷藏过程中氨基酸代谢和碳水化合物代谢为最主要的代谢通路,日本鲭样品组氨酸、精氨酸、脯氨酸等氨基酸代谢相关基因和丁酸丁酯代谢、丙酸酯代谢及丙酮酸代谢丰度均显著高于同一时期的大黄鱼,本实验从微生物代谢水平解释了日本鲭比大黄鱼更易腐败的原因,为不同水产品腐败特性的研究提供新思路。  相似文献   

15.
ABSTRACT

The objective of this study was to determine the microbiological quality of farmed giant freshwater prawn (Macrobrachium rosenbergii) collected from four freshwater farms located in Kerala (India). Microbiological counts on whole, deheaded, and deheaded and deveined prawn as well as on head and intestine were determined. Average counts (log10 cfu g?1) on whole prawn were 6.9 (total mesophilic counts (TPC) at 37°C) and 4.1 (psychrotrophic count at 7°C). The results indicated that the aerobic counts were within the acceptable limit. The levels of enterococci and faecal coliforms in farmed M. rosenbergii were high. There was an increase in the numbers of enterococci and Staphylococcus aureus after deheading. The major groups of bacteria comprising the flora of M. rosenbergii were Aeromonadaceae, Enterobacteriaceae and Pseudomonas. Farmed M. rosenbergii carried pathogenic bacteria such as Enterococcus spp., S. aureus, Aeromonas hydrophila, A. veronii biovar sobria and Clostridium perfringens. The results of the study suggest adoption of good farming and post harvest practices to improve the microbiological quality of farmed freshwater prawn.  相似文献   

16.
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 (< 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 (< 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 (< 0.05).  相似文献   

17.
ABSTRACT

This study analyzes microbiological changes in whole, ungutted farmed gilthead sea bream (Sparus aurata) stored for an 18-day period in ice using traditional methods for mesophilic aerobic bacteria, psychrotrophic, Pseudomonas spp., Aeromonas spp., Shewanella putrefaciens, Enterobacteriaceae, sulphide-reducing Clostridium (Clostridia), and Photobacterium phosphoreum in muscle, skin, and gills, evaluating their seasonal differentiation. Two different statistical models were used to analyze microbiological growth. Simultaneously, physicochemical parameters such as the temperature, pH, biological oxygen demand (BOD), total dissolved solids, salinity, ammonia nitrogen, and total phosphorus content of growing waters were analyzed. The results showed that by the end of the storage time, specific spoilage bacteria (SSB) such as Pseudomonas spp., Aeromonas spp., and S. putrefaciens as H2S-producing bacteria were dominant in sea bream harvested in temperate water in the Canary Islands. Muscle tissue had the least contamination, followed by skin and gills. The values of the analyzed seawater parameters were constant during the four seasons, except that the temperature showed a small difference between winter and summer. Seasonal effects were observed among the fish analyzed, suggesting that the lower levels of contamination detected in winter may have been due to the slight difference observed in water temperature in that season.  相似文献   

18.
Fish and fish products are characterized for having a short shelf life. Nonthermal processing techniques such as high hydrostatic pressure (HHP) have increasingly been employed to extend shelf life of food products. The aim of this study was to evaluate changes on flesh physicochemical spoilage parameters (pH, total volatile bases (TVB-N), trimethylamine (TMA), thiobarbituric acid (TBA), and color) of palm ruff (Seriolella violacea) fillets in pre- and post-rigor conditions, subjected to two different HHP conditions: 450 MPa and 550 MPa, for 3 and 4 min each. Unpressurized and pressurized fillets were kept in chilled storage (4 ± 1°C) for 26 days to assess the effect of HHP on shelf life. pH and TBA values increased after HHP treatment and with storage time for both unpressurized and pressurized samples. This is attributable to pressure-induced lipid oxidation. Lightness (L*) values increased with pressure, where fish fillets had a cooked appearance. TMA and TVB-N values decreased after HHP treatment compared to the unpressurized samples, showing that HHP treatment is an efficient method to maintain the quality of palm ruff fillets. There was no clear difference between pre- and post-rigor in the parameters evaluated.  相似文献   

19.
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.  相似文献   

20.
Postmortem changes in blue shrimp (Litopenaeus stylirostris) muscle were studied on the basis of biochemical, chemical, physical, and microbiological changes during an 18 day storage period at 0°C. Adenosine 5′-triphosphate (ATP) content, breakdown products, K-value, pH, trimethylamine nitrogen (TMA-N), total volatile basic nitrogen (TVB-N), water holding capacity (WHC), color, and texture (shear force) changes were examined. Also, total mesophilic and psychrophilic bacterial counts were measured. K-value increased linearly (r2 = 0.98) from an initial value of 1.37 ± 0.59 to 59.42 ± 6.05% at Day 18. Spoilage indicators TVB-N and TMA-N increased from 29.56 ± 1.33 and 0.69 ± 0.25 to 39.04 and 2.04 ± 0.59 mg of N/100 g at Day 18, respectively; meanwhile, the total viable counts of mesophilic and psychrophilic bacteria increased from 3.48 ± 0.44 and 2.61 ± 0.29 log CFU/g to 6.27 ± 0.21 and 7.14 ± 0.39 log CFU/g, respectively, which indicated spoilage at the end of the storage period. The pH, texture, WHC, and color were affected (p < 0.05) during the storage period. Overall, results indicate that blue shrimp muscle quality was maintained for 12 days of storage in ice.  相似文献   

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