Preparation of Chitosan/Rosemary Extract Nanoparticles and their Application for Inhibiting Lipid Oxidation in Grass Carp (Ctenopharyngodon idellus) during Cold Storage

This study investigated a preparation of chitosan/rosemary extract nanoparticles (CS/RE-NPs) based on the principle of ionic gelation and their application for inhibiting grass carp lipid oxidation. CS/RE-NPs were found to have a rosemary extract (RE) encapsulation efficacy of 40.33%, average particle size of 199.90 nm, and zeta-potential of 35.60 mV. Structural analysis using UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM) indicated that the RE s were well incorporated into the CS-NPs. Treatment of the CS/RE-NPs inhibited lipid oxidation of the grass carp during cold storage, and the peroxide value (PV), thiobarbituric acid-reactive substance (TBARS) value, and lipoxygenase (LOX) activity of the CS/RE-NP-treated samples were lower than those of RE and CS-NP-treated samples, respectively. CS/RE-NP-treated samples also slowed the growth of bacteria, enhanced the organoleptic quality, and prolonged the shelf life of grass carp. This study suggested that CS/RE-NPs can be used as an antioxidant delivery system to inhibit lipid oxidation and improve food quality.     

Influence of Previous Washing Process and Storage Time on Chemical Composition and Sensory Quality of Thai Pangas (Pangasius sutchi) Minced Muscle During Frozen Storage

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.     

Influence of Dietary Lipid and Protein Sources on the Sensory Quality of Organic Rainbow Trout (Oncorhynchus mykiss) After Ice Storage

The influence of dietary protein and lipid sources on the quality of organic rainbow trout (Oncorhynchus mykiss) was studied. The protein and oil sources were fishmeal, fish oil, and organic vegetable protein and oils. Sensory profiling was performed during 3 to 14 days of ice storage along with lipid analyses of the fillet. Overall, the results showed that the sensory characteristics of the trout were affected in different ways during ice storage. The source of lipid seemed to affect the sensory quality at the beginning of the storage period, while the protein source seemed to have a more pronounced impact at the end of the storage period.     

Control of Lipid Oxidation and Texture Changes in Frozen Sardine Mince by Combined Use of Milk Protein Concentrate and Caffeic Acid

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.     

Effects of Whitening Agents and Frozen Storage on the Quality of Sardine (Sardina pilchardus) Surimi: Physicochemical and Mechanical Properties

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.     

Evaluation and Optimization of Chemical Treatments for Reducing Yellow Discoloration of Channel Catfish (Ictalurus punctatus) Fillets During Cold Storage

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.     

Coloration Characteristics of Mechanically Processed Channel Catfish (Ictalurus punctatus) Fillets Held in Refrigerated Storage for Seven Days

Abstract

A project was initiated to investigate coloration (L*, a*, b*; Commission Internationale de l'Eclairage 1976) characteristics of mechanically processed channel catfish (Ictalurus punctatus) fillets. Experienced personnel were evaluated in their efficacy of visual organization of fillets into four distinct yellowness (b*) coloration categories. There was a significant (P < 0.001) difference in yellowness only between the two extreme categories, suggesting the need for development of physical coloration standards.

Coloration was measured at six sites per fillet ≤24 h post processing and after seven day refrigerated (4°–5°C) storage. There was a significant (P < 0.001) increase in overall lightness (L*) from 58.9 ± 5.2 to 60.1 ± 2.3. There was a significant (P < 0.001) increase in the overall mean yellowness (b*) value from 0.8 ± 3.2 to 1.9 ± 3.8. Most individual fillet sites exhibited a significant increase in yellowness.     

The Influence of Cooking Parameters and Chilled Storage Time on Quality of Sous-Vide Atlantic Mackerel (Scomber scombrus)

The aim of the present study was to evaluate the effects of various sous-vide time–temperature regimes and their interactions on quality parameters of Atlantic mackerel (Scomber scombrus) during chilled storage. The mackerel ?llets were exposed to sous-vide treatment at 60, 75, and 90°C for 10, 15, and 20 min and further stored for 1, 3, and 7 days at 4 ± 1°C before analysis. Changes in pH, water content and cook loss, amount of water- and salt-soluble proteins, texture, and color parameters, as well as accumulation of lipid oxidation products in sous-vide-cooked mackerel were assessed. Sous-vide cooking time and temperature had the lowest contribution to the formation of primary and secondary products of lipid oxidation, as well as increase in yellowness of the fish flesh due to their accumulation; whereas duration of chilled storage led to a significant increase in oxidation and yellowness (p < 0.05). Duration of chilled storage also affected structural and textural properties of the fish muscle, leading to a decreased cook loss. At the same time, sous-vide cooking decreased the firmness of the fish muscle. Duration of chilled storage was found to have the highest significant effect (p < 0.001) on all physicochemical characteristics of sous-vide-cooked mackerel.     

Influence of the Dietary Addition of Butylated-Hydroxytoluene and Lipid Level on the Flesh Lipid Quality of Beluga Sturgeon (Huso huso) During Frozen Storage

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.     

Improvement of Cold and Thermally Induced Gelation of Giant Squid (Dosidicus gigas) Surimi

Depending on the season of capture, giant squid (Dosidicus gigas) surimi processed by isoelectric precipitation presents low gel strength. Addition of microbial transglutaminase (MTGase) and application of high isostatic pressure (300 MPa) to improve physicochemical properties were assayed for purposes of making “suwari” gels and heated gels for use in restructured products which have a raw or cooked appearance. The physicochemical properties of both pressurized and unpressurized gels induced by application of 30°C/1 h improved when MTGase was added. In contrast, addition of MTGase was less effective in gels subsequently heated at 90°C/30 min after 30°C/1 h. High pressure treatment for 30 min at 300 MPa and 15°C helped to produce gels with better mechanical and water binding properties, whether treated for 30°C/1 h only or for 30°C/1 h plus 30-min heat treatment at 90°C. High pressure treatment also reduced lightness.     

Lipid Oxidation and Omega-3 Fatty Acid Retention in Salmon and Mackerel Nuggets During Frozen Storage

The extent of lipid oxidation and retention of omega (ω)-3 fatty acids in milk protein concentrate (MPC)-added mackerel and salmon mince and nuggets during 4-months frozen storage were investigated in order to develop high ω-3 seafood products. Mechanically deboned fish mince formulated with MPC and other ingredients was formed into batter-breaded nuggets with or without par-frying. The addition of MPC at 4% resulted in significantly lower thiobarbituric acid reactive substances (TBARS) values and helped retain significantly (p < 0.05) higher amounts of docosahexaenoic acid (DHA) in both salmon and mackerel mince and eicosapentaenoic acid (EPA) in the mackerel mince. There were no significant differences in peroxide values (PV) and TBARS values between nugget products with and without par-frying. EPA and DHA were retained less in par-fried than raw nuggets probably due to oil leaching and thermal degradation during frying. The reductions of EPA and DHA in salmon were 67% and 53% for raw and 57% and 39% for par-fried nuggets, while in mackerel they were 63% and 73% for raw and 57% and 56% for par-fried nuggets, respectively. Results suggest that although MPC provided some protection against lipid oxidation, additional measures are needed to improve retention of ω-3 fatty acids in mince-based seafood products during frozen storage.     

Changes in Protein Oxidation,Water-Holding Capacity,and Texture of Bighead Carp (Aristichthys Nobilis) Fillets Under Chilled and Partial Frozen Storage

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.     

Lipolysis and Lipid Oxidation during Processing of Chinese Traditional Dry-Cured White Amur Bream (Parabramis pekinensis)

Lipolysis and lipid oxidation of intramuscular lipids during the dry-curing process of white amur bream (Parabramis pekinensis) were studied. All lipolytic enzyme activities decreased (p < 0.05) at the end of the process. The lipoxygenase activity increased during wet-salting (p < 0.05) and then decreased until the end of the process (p < 0.05). The daily variation of free fatty acids was correlated with those of the peroxide value (r = 0.976, p < 0.01) and thiobarbituric acid-reactive substances (r = 0.922, p < 0.01), respectively. These results suggest that lipolysis promotes lipid oxidation during the processing of dry-cured fish.     

Influence of Varying Dietary Protein Content at Three Lipid Concentrations on Growth Characteristics of Juvenile Swordtails (Xiphophorus helleri Heckel 1848)

Three protein levels (30%, 38% and 45%) at three different dietary lipid concentrations (6%, 8% and 12%) were used to formulate nine different diets that were fed for 60 days to 6–8 weeks old juvenile swordtails (Xiphophorus helleri). It would appear that a diet of at least 45% protein at a 6% lipid concentration is needed for the best specific growth rate (1.27% per day) and feed conversion ratio (2.50) at this specific growth phase in X. helleri. No ‘protein sparing effect’ was found when lipid concentration was increased at lower protein levels. This revised version was published online in August 2006 with corrections to the Cover Date.     

Response of African Catfish, Clarias gariepinus, to Different Dietary Protein and Lipid Levels in Practical Diets

This study was conducted to find the optimum level of dietary protein and lipid that could produce the highest growth, best feed utilization, and body composition of African catfish, Clarias gariepinus (9.5–10.3 g). Nine diets (three protein levels × three lipid levels) containing 25, 30, or 35% crude protein (CP) with 6, 9, and 12% lipids were formulated. Fish were fed one of the tested diets at the rate of 5% of body weight for the first 8 wk and 3% for the rest of the study. Diets were offered 6 d a week, twice a day (900 and 1400 h) for 13 wk. Fish growth increased significantly with increasing either protein or lipid levels, and the maximum growth was obtained in fish fed diets containing 30% CP with 12% lipid or 35% CP with 9% lipid. The lowest fish growth was obtained at 25% CP with 6% lipid. The optimum feed intake, feed conversion ratio, energy utilization, protein efficiency ratio, and protein growth rate were also recognized in fish fed the above diets. No significant differences in moisture and ash contents in fish fed diets containing different protein and lipid levels were recorded. The protein and lipid contents in the fish body tended to increase with increasing protein and lipid levels in diets. However, the higher protein contents were obtained in fish fed diets containing 35% CP with 6 or 9% lipid, while the lowest ones were obtained at 25% CP with 6 or 9% lipid. The higher lipid contents were obtained at 30 or 35% CP with 12% lipid, while the lowest ones were obtained at 25 or 35% CP with 6% lipid. The present study indicates that the increase of dietary lipid level has a protein-sparing effect, and the diet containing 30% CP with 12% lipid would be suitable for the optimum growth and effective protein utilization of fingerling African catfish.     

寒冷地区革胡子鲶早期人工繁殖试验

为了解决寒冷地区革胡子鲶苗种自繁自育问题,在１９９６年１０月初从本单位养殖革胡子鲶的商品鱼中选择备用亲鱼,利用甲鱼场的温室大棚池和设备进行冬季培育,１９９７年元月进行强化饲养,同年２月１８日进行人工早繁试验,先后繁殖并培育出３～２０厘米的苗种近２０万...     

Protein and Energy Levels for Maximum Growth, Diet Utilization, Yield of Edible Flesh and Protein Sparing of Hybrid Clarias Catfish (Clarias macrocephalus×Clarias gariepinus)

Abstract— Two feeding trials were performed to determine dietary protein and energy levels for maximum growth, diet utilization, yield of edible flesh and protein sparing of hybrid Clarias catfish ( Clanas macrocephalus × Clarias gariepinus ). A 3 × 3 factorial design was employed for experiment 1 in which nine diets containing either 20, 30 or 40% protein and 275, 300 or 325-kcal digestible energy/100 g were used. The follow-up experiment 2 was a 3 × 2 factorial in which three protein levels (30, 35 and 40%) and two digestible energy levels (275 and 325 kcal/100 g) were tested. Dietary ingredients used in both studies were similar but the ratios of energy provided by dextrin and lard were 11.3/1.0 and 3.8/1.0 for experiments 1 and 2, respectively. Each of the experimental diets was fed to apparent satiation twice daily to three aquaria of fish (15 fish/aquaria) with average weight of 4.0 and 2.0 g for experiment 1 and 2, respectively, for 8 wk. Performance of fish in experiment 1 was mainly influenced by dietary protein rather than by energy levels. Maximum growth and diet utilization were attained at dietary protein and energy levels of 40% and 275 kcal/100 g, respectively. Energy levels did not spare dietary protein in experiment 1. In experiment 2, growth, diet utilization, and yield of edible flesh of fish were influenced by protein and energy levels. Furthermore, the protein sparing effect was observed in experiment 2. Best performance and protein sparing were found at 35% protein and 325-kcal digestible energy/100 g. The studies showed that dietary protein and energy requirement for hybrid Clarias catfish are affected by carbohydrate to lipid ratio. Fish utilize dietary energy with a dextrin to lard ratio of 3.8/1.0 more efficiently than that with a ratio of 11.3/1.0. Therefore, dietary protein and energy for best performance and protein sparing of hybrid Clarias catfish reported for experiment 2 were more appropriate.     

Effects on Lipid Oxidation and Bioactive Properties of Rainbow Trout Fillets Fed with Barley

Barley concentrations ranging from 0% to 32% were incorporated into rainbow trout (Oncorhynchus mykiss) diets. The effect of barley concentration on lipid peroxidation and antioxidant activity of fish fillets were analyzed. Results showed that the inclusion of barley in rainbow trout diets had an inhibitory effect on lipid oxidation, probably associated with certain bioactive compounds in barley that could interact with scavenging and reducing metabolites involved in lipid oxidation. Concentrations up to 8% of barley produced fish fillets with high antioxidant activity and higher levels of alpha-tocopherol.     

Study on Gel Properties of Silver Carp (Hypophthalmichthys molitrix) and White Croaker (Argyrosomus argentatus) Blended Surimi at Different Setting Conditions

Gel properties of blends of surimi from silver carp and white croaker set for a range of times and at different temperatures were evaluated for breaking force, breaking distance, and whiteness. Total protein content was 12% in all samples, and the concentration of white croaker surimi protein in the blends was designed at 0, 10, 20, 30, and 40%. The blended surimi had greater gel strength than either of the two types of surimi alone. Breaking force and breaking distance after setting were also significantly higher than that of the blended surimi cooked directly without setting. The blended surimi exhibited less modori than either of the two types of surimi alone heated to 50°C. The whiteness values of the blended surimi were significantly higher than that of white croaker alone. These results indicate there are advantages to be gained in utilizing surimi from freshwater silver carp in blends with surimi from marine captured white croaker which is becoming limited in supply.