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1.
Cod (Gadus morhua) was stored at eight temperatures (?10 to ?80°C) for 1 to 18 months, after which quality indicators were measured—including drip loss, water holding capacity, low field NMR spin-spin relaxation, color, amount of thiobarbituric acid reactive substances, and sarcoplasmic reticulum Ca2+-ATPase and lysosomal Cathepsin D activities. Results from samples stored up to 12 months showed no significant differences between ?30°C and lower temperatures. The NMR measurements, however, indicated some changes in the water distribution of samples stored at ?30°C for 12 or more months compared to storage at ?40°C or lower.  相似文献   

2.
This work is focused on the effect of using whitening agents (WA) during a process followed by frozen storage (4 months at ?18°C) on the whiteness, quality parameters, and mechanical properties of sardine surimi. The whiteness of surimi exhibited a significant improvement when whitening agents (calcium carbonate and peroxide hydrogen) were used (48.75 to 60.24). Dynamic rheological measurement showed that storage moduli, G′, was considerably higher than loss moduli, G″, for both surimi with WA and control; however, the highest viscoelastic moduli were found in the treated surimi. In addition, the microstructure of surimi with WA showed more compact matrix and higher water holding capacity. On the other hand, most tested indexes showed quality losses throughout the frozen storage in both samples. Proteins underwent denaturation as indicated by the reduction in band intensities, especially myosin heavy chain (MHC) bands. Peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) measurements showed that lipid oxidation took place during storage; however, the degree of lipid oxidation was not relevant. Therefore, it was proved that the addition of whitening agents had a marked effect on the production of surimi with better functional attributes including whiteness, water holding capacity, and mechanical properties.  相似文献   

3.
ABSTRACT

The effects of a short chilled storage period before freezing, frozen storage temperature, and freezing rate on lipid oxidation of bluefin tuna (Thunnus thynnus) meat during frozen storage were investigated. After 12-months storage, all samples had increased in peroxide value though they were less at the lower temperatures (?45 and ?60°C). Peroxide values in all samples stored at ?20°C increased after 3 months storage, particularly those processed and stored 51 h after harvest. The lowest increase in peroxide value occurred in the samples frozen rapidly 3 h after harvest. Vitamin E levels decreased faster during frozen storage at ?20°C. There were no apparent differences in levels of triacylglycerides nor in n-3 fatty acid levels between treatments, storage periods, and storage temperatures. After 12-months storage, headspace oxidative volatiles were highest in samples stored at ?20°C and lowest in those stored at ?60°C. Lipid oxidation in tuna meat stored at ?45°C is similar to that at ?60°C, and rapid freezing rather than slow freezing should be used.  相似文献   

4.
This study compares how CO2 narcosis and thermal shock affect the physicochemical aspects of Nile tilapia fillets held frozen (?18°C) for up to 6 months. The characteristics of tilapia fillets subjected to CO2 narcosis were those of higher lightness and whiteness and lower redness. The hardness values of fillets of tilapia subjected to thermal shock were lower than those subjected to CO2 narcosis. During frozen storage to both treatments, the drip loss, denaturation of myosin, and lipid oxidation increased, while fillet water holding capacity and hardness decreased. The physicochemical properties of frozen fillets of tilapia stunned by CO2 narcosis were considered more desirable; therefore, the method can be a potential replacement to thermal shock.  相似文献   

5.
The aim of this study was to investigate the effects of freezing and frozen storage on protein functionality and texture of squid (Loligo vulgaris), octopus (Octopus vulgaris), and cuttlefish (Sepia officinalis) muscles. Squid, octopus, and cuttlefish samples were cut into pieces of 4 × 4 cm. These pieces were packed in polyethylene bags. The bags were frozen in a blast freezer at ?45°C until the thermal center reached ?18°C. Frozen samples were stored in a deep freezer at ?18°C for 30 days. After freezing and during frozen storage, total soluble protein and water holding capacity decreased and total free amino acid and cooking loss increased in all cephalopod muscles. According to instrumental texture analysis results, freezing and frozen storage affected textural characteristics of squid and cuttlefish but not of octopus. Sensory hardness and chewiness values of all cephalopods increased after freezing, but elasticity values did not change. There were no significant differences between storage days in hardness values of squid and octopus. However, significant differences in hardness values of cuttlefish were observed between the 1st day of storage and the last day.  相似文献   

6.
The effect of single and double freezing at ?20°C on fresh and aged red hake with two different holding times of the thawed fillets between the first and second freezing treatments was determined. In addition, twice-frozen fresh red hake was treated with two antioxidation systems to assess their effectiveness in reducing lipid oxidation. Fresh, untreated red hake at 0 time was used for comparison. Significant dimethylamine (DMA) production occurred with all frozen samples, and the differences were not marked after 7-month storage. With a storage time of 3 months, however, there were differences between the treatments in both the fresh and aged samples with the once-frozen sample producing the least DMA, the twice-frozen sample with the 24-h holding time between freezings the most, and the twice-frozen sample with a 6-h holding time between freezings giving intermediate values. All samples showed a greater than 50% loss in protein solubility as determined by lithium chloride extraction after 3 months of storage, and the protein solubility declined further when samples were tested at 7 months. Samples with the best (once-frozen fresh) and worst (twice-frozen with 24-h holding time between freezings of 5-day aged muscle) treatments had the highest thiobarbituric acid-reactive substances (TBARS) values. Both antioxidant treatments were effective in reducing TBARS development.  相似文献   

7.
Quality changes of vacuum-packed Atlantic mackerel (Scomber scombrus) fillets during 12 months’ frozen storage at ?27°C and 9 days’ chilled storage at +4°C were evaluated. Freezing at ?27°C preserved the long chain n-3 polyunsaturated fatty acids (LC n-3 PUFAs), both in light and dark muscle, vitamin D, and the low molecular weight metabolites (LMW) (studied by high resolution nuclear magnetic resonance spectroscopy, HR NMR). Protein oxidation took place, especially between 1 and 7 months, decreasing water holding capacity and protein extractability. During chilled storage, no lipid or protein oxidation was observed, but lipolysis increased, and several LMW metabolites relevant for sensory and nutritional quality degraded into non-favorable compounds. The content of biogenic amines was high at day 9 (e.g., 18 mg histamine/100 g), jeopardizing safety. Preservation of mackerel fillets by freezing at ?27°C is thus a better option compared to prolonged chilled storage at +4°C; the quality was well preserved for 12 months’ frozen storage.  相似文献   

8.
The aim of this study was to determine the textural and sensory properties of fish sausage which were prepared from refrigerated and frozen rainbow trout (Onchorynchus mykiss) and stored for 14 days at 0?4 °C. These two groups of sausages were compared for texture, physical, and sensory properties by carrying out texture profile analysis (TPA), shear test, water holding capacity (WHC), cook loss, color, and sensory analyses. According to TPA and shear test, sausages prepared from frozen fillets exhibited a texture significantly (p < 0.05) weaker than those prepared from refrigerated fillets, but no difference in overall liking was observed.  相似文献   

9.
This study aimed to evaluate the contribution of protein oxidation to the changes in the water-holding capacity (WHC) and texture of bighead carp (Aristichthys nobilis) fillets under chilled and partial frozen storage (4°C and ?3°C). The results indicated that less protein oxidation occurred to fillets at ?3°C than at 4°C, which was reflected by the higher value of salt-soluble protein contents (SSP), total sulfhydryl content (SH), Ca2+-ATPase activity, lower water-soluble protein contents (WSP), total disulfide content (SS), and surface hydrophobicity (So-ANS). However, the fillets had better WHC and texture at 4°C, as well as lower drip loss and higher centrifugal loss, hardness, and springiness. A significant linear relationship existed between protein oxidation parameters with WHC and texture characteristics for fillets under both types of storage, but the process of freezing and then thawing, instead of protein oxidation, was the main factor affecting the texture and WHC of fillets at ?3°C.  相似文献   

10.
This study evaluated the physicochemical changes in Nile tilapia (n = 82, 373.71 ± 61.91 g) refrigerated for up to 92 h and in the frozen fillets. The tilapias were captured with nets, slaughtered by ice and water shock (1:1) in a temperature of approximately 2°C for 30 min, and stored refrigerated at 4°C in polystyrene boxes containing ice. The fish were filleted, and filets were weighed and frozen. The drip loss and protein were determined after 23 days of frozen storage. After 4 h of storage, all fish were in full rigor mortis. The pH of the muscles decreased for up to 45 h of the storage period. The fillets obtained from tilapia stored for more than 72 h lost more weight and protein. Thus, the filleting or processing of tilapia should be done before 72 h of cold storage, since deterioration of the fish starts to occur after this period.  相似文献   

11.
Atlantic mackerel was stored at refrigeration or frozen temperatures under vacuum or in air with various treatments to determine lipid hydrolysis and oxidation in the fish muscle. Lipid oxidation in the fish minces occurred continually as long as the samples were exposed to air independent of hydrolytic activity which was deactivated or retarded by cooking the sample or by lowering the storage temperature (-40°C). Lipid oxidation was observed not only in the free fatty acids, but also in the triacylglycerides and the phospholipids extracted from mackerel mince.  相似文献   

12.
The effectiveness of milk protein concentrate (MPC) and caffeic acid in controlling lipid oxidation and texture changes in 6-month frozen stored sardine mince was investigated using two different concentrations of caffeic acid (200 and 400 ppm) with and without MPC (4%). The extent of lipid oxidation was monitored by measuring thiobarbituric acid reactive substances (TBARS) while changes in the texture of mince due to frozen storage were assessed using Texture Analyzer (TA.XT Plus) and sensory analysis. Cooking loss upon frozen storage was also determined. The addition of MPC and/or caffeic acid significantly reduced lipid oxidation throughout the storage period. However, neither added benefit nor synergistic effect in retarding lipid oxidation was shown by caffeic acid. MPC not only retarded lipid oxidation but also moderated texture hardening, cooking loss, and moistness during frozen storage. No improvement by caffeic acid alone and no significant differences in sensory firmness and moistness between MPC-added mince with and without caffeic acid indicate that caffeic acid did not play any role in texture and moisture control. This study suggests that lipid oxidation and texture of frozen sardine mince can be better controlled by using MPC alone.  相似文献   

13.
The effects of storage temperature and time on raw pink salmon by-products were evaluated in relation to the fishmeal produced. Chemical analyses were performed on the raw and processed by‐products at two temperatures. Total volatile base nitrogen values indicated substantial spoilage by day 2 at 15.4 ± 1.4°C and day 6 at 6.0 ± 0.8°C. For most biogenic amines in raw by-products stored at 15.4°C, there were many significant differences from the fresh by-products by day 2. For by-products stored at 6.0°C, significant changes in biogenic amine were evident by day 2 and continued to increase. The thiobarbituric acid reactive substances (TBARS) values of the raw material stored at 15.4°C started showing significant changes from fresh on day 3 and at 6.0°C on day 4. The lipid oxidation (TBARS) was significantly different from fresh by day 2. Biogenic amines in fishmeals suggested some changes occurred between day 0 and day 3 at 15.4°C and by day 7 at 6.0°C.  相似文献   

14.
The technological effect of antioxidant dietary fiber (AODF) from Fucus vesiculosus added to minced horse mackerel (Trachurus trachurus) during frozen storage was tested. Fish mince (FM) samples supplemented with 1 and 2% AODF were compared to AODF-free control. Dietary analysis, antioxidant capacity, total polyphenols content, ferric-reducing antioxidant power (FRAP assay), and free radical scavenging activity (by ABTS assay), water binding capacity, water holding ability, cooking yield, and sensory analyses were carried out just after freezing and during frozen storage. Samples with 1 and 2% of AODF added had lower lipid oxidation than those without AODF, and the total drip (thaw + cooking) was reduced after 3 months of frozen storage. Fish samples supplemented with 1% AODF did not have a different flavor from the control. Samples supplemented with 2% AODF had a different flavor from the control, but this did not impair palatability.  相似文献   

15.
ABSTRACT

Ovalipes trimaculatus is a crab recognized as a new resource with fishing value to obtain frozen products. Pasteurization conditions of meat crab at temperatures below 85ºC (60, 72, and 82ºC) were established to achieve better quality attributes in the frozen product. The lethality curves of Staphylococcus aureus and Listeria monocytogenes were measured, and the decimal reduction times (D) and Z values were determined. Heat transfer during the pasteurization process of pouches containing crab meat was simulated using a computational code in finite elements, and the mathematical model was experimentally validated. Thermal histories were coupled to the microbial lethality kinetics of the most heat resistant pathogen microorganism in order to establish pasteurization times necessary for the process system design. The predicted pasteurization conditions were microbiologically validated. The pouches were frozen under industrial conditions and stored at ?22ºC for 1 year. The influence of the type of packaging (vacuum and nonvacuum plastic pouches) on physicochemical and sensory quality parameters of frozen crab meat (color, exudate, lipid oxidation, water holding capacity, and overall acceptability) were analyzed observing better performance under vacuum conditions.  相似文献   

16.
ABSTRACT

This work focuses on the effect of a washing process followed by frozen storage (3 months; ?18°C) on the quality of minced pangas muscle. A previous washing step has led to a positive effect on fish quality according to marked decreases in expressible moisture (28%), volatile amines (25.7%), free fatty acids (24.5%), and thiobarbituric acid reactive substances (29%). However, such indexes showed quality loss throughout the frozen storage. Amongst quality indexes, special attention should be given to the expressible moisture value and the water holding capacity, as being closely related to the gel-forming ability in order to obtain surimi-type commercial products.  相似文献   

17.
The kinetics of astaxanthin degradation and lipid oxidation in shrimp oil from hepatopancreas of Pacific white shrimp (Litopenaeus vannamei) as affected by storage temperature were studied. When shrimp oil was incubated at different temperatures (4, 30, 45 and 60 °C) for 16 h, the rate constants (k) of astaxanthin degradation and lipid oxidation in shrimp oil increased with increasing temperatures (p < 0.05). Thus, astaxanthin degradation and lipid oxidation in shrimp oil were augmented at high temperature. When shrimp oils with different storage conditions (illumination, oxygen availability and temperature) were stored for up to 40 days, astaxanthin contents in all samples decreased throughout storage (p < 0.05). All factors were able to enhance astaxanthin degradation during 40 days of storage. With increasing storage time, the progressive formation of primary and secondary oxidation products were found in all samples as evidenced by the increases in both peroxide values (PV) and thiobarbituric acid reactive substances (TBARS) (p < 0.05). Light, air and temperatures therefore had the marked effect on astaxanthin degradation and lipid oxidation in shrimp oils during the extended storage.  相似文献   

18.
Changes in quality parameters including pH, water activity, texture, and lipid oxidation were studied in pasteurized chum salmon (Oncorhynchus keta) ikura samples packaged using two films with different oxygen transmission rates (OTR) (40 and 62 cm3·m?2·day?1; F-40 and F-62), during 60 days storage at 4°C. No significant differences in pH and water activity (aw) were observed between ikura packaged using two different films with different OTR (P > 0.05). However, compared to the first day of study, water activity decreased significantly in ikura (P < 0.05). Ikura thiobarbituric reactive substance (TBARS) in the pouches significantly increased during the storage at 4°C (P < 0.05). Both pouches showed similar trends in TBARS until day 29, while after day 29, ikura packaged in F-62 (OTR = 62 cm3·m?2·day?1) showed a significant increase in TBARS compared to F-40 with less OTR (P < 0.05). The texture of ikura became softer compared to the first day; however, no significant difference was observed between the ikura samples in two pouches (P < 0.05). The quality changes of ikura measured during storage indicate that packaging ikura in a lower OTR film would provide greater quality retention than one with higher OTR.  相似文献   

19.
This study examined how muscle metabolic organization varied during an annual cycle in which rainbow trout (Oncorhynchus mykiss) were held in outdoor holding ponds in which they were exposed to natural changes in temperature (range 0.2 to 15.6°C) and photoperiod. We examined the activities of glycolytic and mitochondrial enzymes in red and white muscle to evaluate whether trout enhance their capacity for lipid and carbohydrate oxidation during cold-acclimization. When assayed at habitat temperature, the enzyme activities generally increased in spring to reach a maximum in summer followed by a decrease in the fall. This led to significantly higher activities at warm than cold periods for all enzymes measured in red muscle and all but one in white muscle. The activities at 10°C provided little evidence for compensatory adjustments of aerobic capacity. Particularly in red muscle, enzyme levels at 10°C were generally lower during cold than warm periods. The variation of enzyme activities throughout the cycle was not due to changes in protein concentration, as the same responses were observed when activities were expressed per g wet mass or per mg protein. Although the aerobic capacity did not increase with cold-acclimatization, the relative capacity for lipid oxidation was higher in winter than in summer trout. In contrast, the relative capacity for aerobic glycolysis was higher in summer than in winter trout. Thus, the metabolic capacities of trout muscle undergo seasonal reorganization.  相似文献   

20.
The main aim of the present work was to evaluate the effect of dietary butylated-hydroxytoulene (BHT as an antioxidant) and dietary lipid level on flesh lipid quality of Beluga sturgeon during frozen storage. An initial 135-day feeding trial evaluated practical-type diets containing 0 or 250 mg BHT kg?1 with two lipid levels (12 and 24% diet on dry matter basis) in a factorial arrangement. Fillet samples were analyzed fresh or after storage at ?18 ± 1°C for 12 months. Dietary antioxidant supplementation had no significant effect on fat content and fatty acid composition in the studied fish muscle, but increasing the lipid concentration in the feed increased muscle lipid concentration. Lipid oxidation in fish muscle is related to increasing lipid concentration in the feed. In addition, oxidation was reduced for fish fed BHT. Results showed that dietary BHT supplementation can slow down the level of lipid oxidation in Beluga sturgeon muscles during frozen storage, but it had a direct relationship with dietary lipid level.  相似文献   

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