Postmortem Changes in the Adductor Muscle of Scallop (Chlamys tehuelchus) in Chilled and Frozen Storage

Abstract

The effects of freezing and frozen storage on the biochemical properties of scallop adductor muscles stored at 2-4EC were investigated. Glycogen content fell 40% in the first 12 hr of chilled storage and decreased slowly thereafter. ATP content increased for a short time after death and then decreased slowly. Glycogen and ATP degradation was accompanied by a decrease in both pH and 260/250 absorbance ratio of scallop muscle extracts. A significant increase (p < 0.05) in the hypoxanthine (Hx) content was also observed in chilled stored adductor muscles. Adductor muscles showed a significant decrease (p < 0.05) in the 260/250 absorbance ratio of extracts and an increase in the Hx level after freezing. An increase in Hx content was observed during frozen storage of adductor muscles frozen immediately after processing. Expressible juice increased with freezing and frozen storage of the muscles. The results shown in this paper indicate a rapid loss of quality in scallop adductor muscles during storage at 2-4. Freezing and frozen storage enhanced the quality deterioration of the muscles.     

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.     

Preservation of Black Tiger Shrimp Penaeus monodon Spermatophores by Chilled Storage

Chilled storage of spermatozoa in fish has been extensively investigated for many years, but limited research was focused on crustacean species. Chilled storage of spermatophores of black tiger shrimp Penaeus monodon is needed to generate consistent and reliable supply of spermatozoa for subsequent use. The objective of this study was to develop a protocol for the chilled storage of black tiger shrimp spermatophores and to evaluate bacterial propagation during chilled storage of spermatophores. In the first experiment, spermatophores were selected and preserved using four different extenders, namely mineral oil, Ringer's solution, phosphate buffer and 0.85% sodium chloride, and stored at low temperature (2‐4 C) for 42 d without antibiotic supplementation. Results showed that mineral oil was the best extender for chilled storage of spermatophores, since the highest percentage of viable sperm (58.3 ± 2.9%) was observed with this extender at the end of experiment (day 42). Bacillus sp., Staphylococcus sp., and Pseudomonas aeruginosa were identified as the predominant bacteria occurring during chilled storage, and the total bacteria count gradually increased during the experiment. In the second experiment, spermatophores were preserved in the mineral oil with four concentrations of the antibiotic, penicillin‐streptomycin (0.1%,1%, 2%, and 3%). There was no significant difference (P 0.05) in the percentage of viable sperm among treatments with 0.1%,1 %, 2%, and 3% antibiotics. The total count of Bacillus sp., Staphylococcus sp., and P. aeruginosa in the antibiotic treated groups significantly decreased (P < 0.05) to undetectable levels by day 14 of the experiment. Fertility studies from artificial insemination indicated that P. monodon spermatophores preserved with mineral oil for 7‐8 d at 2‐4 C were capable of fertilizing eggs with hatching rates similar to the controls. This study suggests that chilled storage of spermatophores is a feasible approach for the management and spawning of black tiger prawn broodstock or other Invertebrate species that produce spermatophores.     

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.     

Changes in Functional Properties of Protein in High Pressure-Treated Indian White Prawn (Fenneropenaeus indicus) during Chilled Storage

ABSTRACT

High pressure (HP) treatment of 250 MPa pressure, 6-min holding time, and 400 MPa/min ramp rate at 25°C was applied to headless Indian white prawn (Fenneropenaeus indicus) to investigate the significant modifications on the functional properties of protein during chilled storage. Muscle fibers were shrunk and extracellular space apparently reduced after HP treatment. Myofibrillar proteins denatured and sarcoplasmic proteins aggregated and were found to be stable in HP-treated sample during chilled storage. Water-holding capacity, solubility, viscosity, and Ca²⁺ ATPase activity of protein were diminished, whereas foam expansion, foam volume stability, and turbidity of proteins improved with HP treatment and storage period (p < .05). Turbidity of the protein was inversely proportional to viscosity, solubility, and Ca²⁺ ATPase activity in HP-treated samples.     

Chilled Storage of Pangasianodon hypophthalmus Fillets Coated with Plant Oil Incorporated Alginate Gels: Effect of Clove Leaf,Clove Bud,Rosemary and Thyme Oils

Essential oil incorporated alginate coating provides a novel way to improve the safety and shelf life of pangasius (Pangasianodon hypophthalmus) fillet. Oils from the leaves and buds of clove, flowering tops of rosemary, and dried seeds of thyme were incorporated separately in alginate coating. All the plant oils showed antibacterial activity, but the zone of inhibition was relatively larger for thyme oil. Alginate coating was performed using sodium alginate (1.5%), glycerol (10%), and calcium chloride (2%) and plant oil at 1% (v/v). The coated fillets were stored under chilled conditions and samples were analyzed for bacteriological, chemical, sensory, color, and texture parameters. Psychrotrophic counts crossed 7 log cfu/g by the 13^th day and 15^th day of chilled storage in control and plant oil treated fillets, respectively. The peroxide value of treated fillets was relatively low. Texture profile analysis indicated that plant oil incorporated alginate coating reduced the rate of loss of texture (softening) during chilled storage. Plant essential oil incorporated alginate gels were relatively better compared to control fillets in preserving pangasius fillet quality during chilled storage, and incorporation of thyme oil was relatively better compared to clove leaf oil, clove bud oil, and rosemary oils.     

Chilled storage of banana shrimp (Fenneropenaeus merguiensis) spermatophores with supplementation of moringa (Moringa oleifera Lam.) extract

This study was designed to optimize the chilled storage method for banana shrimp (Fenneropenaeus merguiensis) spermatophores and evaluate the potential of moringa (Moringa oleifera Lam.) extract on the reduction in bacterial contaminants during spermatophore preservation due to the uncertainty of the broodstock. Spermatophores were suspended in five extenders: mineral oil, Ringer's solution, phosphate buffer, calcium‐free saline and 0.8% NaCl and stored at 2–4°C. During a 28‐day storage, spermatophores stored in mineral oil showed the highest sperm viability (89.1%) and intact morphology with a slight formation of hardened adhesive matrices. The effect of moringa extract was investigated on chilled spermatophores. Spermatophores were suspended in mineral oil (the control) and mineral oil containing either penicillin–streptomycin (0.1%) or moringa extract (0.1 mg/ml) during a 28‐day storage. Supplementation of moringa extract resulted in a significant increase (p < .05) in sperm survival, compared to the control, and a complete elimination of culturable Vibrio (Vibrio alginolyticus, Vibrio mimicus and Vibrio furnissii), Staphylococcus kloosii, Bacillus macerans, Listeria ivanovii, Corynebacterium paurometabolum and Corynebacterium bovis, in chilled spermatophores. Chilled storage of spermatophores in mineral oil containing moringa extract was a promising technique due to the inhibition of shrimp and human pathogens without the spermicidal effect on banana shrimp sperm.     

Quality of Filleted Atlantic Mackerel (Scomber Scombrus) During Chilled and Frozen Storage: Changes in Lipids,Vitamin D,Proteins, and Small Metabolites,including Biogenic Amines

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.     

Quality and Shelf Life Assessment of Puffer Fish (Lagocephalus guentheri) Fillets during Chilled Storage

The aim of the study was to quantify the shelf life and quality characteristics of puffer fish, Lagocephalus guentheri, fillets on chilled storage at 2 ± 1°C. The puffer fish muscle contains 16.14% protein, 80.76% moisture, 0.99% ash, and 0.17% fat. The mouse bioassay proved the absence of tetradotoxin in muscle, liver, skin, and gonads of the fish. The polyunsaturated fatty acid to saturated fatty acid (P/S) ratio of puffer fish was found to be 1.3, with n-3 to n-6 ratio of 3.27. The puffer fish had hypocholesterolemic/hypercholesterolemic ratio (H/H) value of 2.68, artherogenicity index of 0.43, and thrombogenicity index of 0.29. Beheaded and deskinned fishes were filleted and were studied for 10 days of chilled storage. The physical, chemical, sensory, and microbiological parameters showed significant (p < 0.05) changes during the entire storage period. While the hydrolytic rancidity was significantly correlated to springiness, gumminess, and chewiness of fillets, the peroxide value (PV) correlated with the color attributes and pH. The hardness of the samples decreased significantly and was evident in both sensory and instrumental analysis. With storage time, the yellowness of the fillets increased steadily. The results of this study can help in improving processing, preservation, and marketing aspects and enhance the utility of puffer fish.     

Texture and Quality Assessment of Ready-to-eat Farmed Obscure Puffer Fish (Takifugu obscurus) Fillet by Evaluating Bacterial and Myofibrillar Degradation and Biochemical Changes during Refrigerated Storage

ABSTRACT

Obscure puffer fish (Takifugu obscurus) flesh, often eaten as raw fish fillet, is susceptible to softening. To investigate the mechanisms for the softening of flesh and changes in firmness, the proliferation of total microbial flora, Enterobacteriaceae, Pseudomonas spp., and lactic acid bacteria (LAB), total volatile basic nitrogen (TVBN), trimethylamine (TMA), and pH were periodically assayed during storage at 0, 4, and 8ºC. Myofibril extraction and separation of puffer fish flesh was carried out and the length of the separated myofibrils was measured periodically using an optical microscope during the entire storage time. Transmission electron microscopy was also used to inspect the changes in myofibrillar characteristics of the fish flesh at the beginning and end of the storage period. The results indicated that lower chilled temperature can contribute to reduced proliferation of microbial flora and less variation in TVBN, TMA, and pH and further maintain the integrity of myofibrils and retain firmness of puffer fish flesh during storage.     

Effect of fasting on physical/chemical properties of ordinary muscles in full-cycle cultured Pacific bluefin tuna Thunnus orientalis during chilled storage

Using the full-cycle cultured (FC) Pacific bluefin tuna [body weight 16.3±1.9 kg (pre-fasting group, pre-FG), 14.2±0.9 kg (post-fasting group, post-FG)], changes in the physical/chemical properties of the cephalal parts of dorsal (D) and ventral (V) ordinary muscles (OM) by fasting (6 days) during chilled storage (4°C) were investigated. Condition factors were 26.7 (pre-FG) and 20.3 (post-FG, P < 0.05). Fasting changed the liver color to green. Fasting also decreased the amount of protein and lipid contents of the DOM and VOM of FC tuna. The breaking strength and pH of the DOM and VOM of post-FG tuna were higher (P <0.05) than for pre-FG tuna during storage. In contrast, the glycogen contents of DOM and VOM of post-FG tuna were lower than for pre-FG tuna. The color values (L*, a* and b*) of DOM of post-FG tuna were lower than for pre-FG tuna throughout the storage period. In addition, the metmyoglobin (metMb) content of DOM of post-FG tuna was lower (P <0.05) than that of pre-FG tuna, and the metMb content of VOM of post-FG tuna remained low after fasting. These results indicate that fasting suppresses deterioration (especially meat color) of FC tuna muscles during chilled storage.     

Quality and Shelf Life of Liver of Farmed Cod (Gadus morhua)

ABSTRACT

Livers of Atlantic cod (Gadus morhua) are traditionally used in cod liver oil production or consumed cooked or canned. The farming of cod is a relatively new industry in Norway. The aim of this study was to determine quality and shelf life of fresh liver from farmed cod during chilled storage on ice by hydrolysis and oxidation state and sensory quality and the influence on canned liver. In two experiments, livers from farmed cod were stored chilled and sampled from Days 0 to 13, respectively. Quality, measured as hydrolytic and oxidation degradation, was reduced after 7 days of storage, while sensory quality was reduced after 4 days. Free fatty acids increased from Day 7 in both experiments, while peroxide value and anisidine value showed no change when the livers were single wrapped. Rancid odor was the first sign of oxidation and was registered after three to four days of storage. Canning within 2 days of storage prevented leakage of oil from the canned livers. Sensory analyses of oxidation are recommended as a sensitive and rapid method to detect oxidation of chilled cod liver.     

Effects of Brief Summer or Winter Fasting on the Muscle Quality of Cultured Pacific Bluefin Tuna (Thunnus orientalis)

The effects of fasting on the quality of the dorsal and ventral ordinary muscles from cultured Pacific bluefin tuna (Thunnus orientalis) during chilled storage were investigated. Tuna were subjected to fasting for 2 days in the summer or 6 days in the winter prior to harvesting. The breaking strength of the dorsal ordinary muscle sampled in the summer increased until 24 h and then decreased. There were no significant differences in the lipid and glycogen content of the ordinary muscle after 9 h of storage between the controls and either fasting group. The pH of the ordinary muscle subjected to summer and winter fasting was higher than in the controls after 24–48 h of storage. However, the relationship between the pH and glycogen content was unclear. The metmyoglobin content during chilled storage was lower in the ordinary muscles from either fasting group than in the controls. In conclusion, fasting for 6 days in the winter improved the color stability of the ordinary muscle without a decline in its lipid content.     

Effects of Injection of Protein Solutions Prepared from Fish By-products on Yield and Chemical Properties of Chilled and Frozen Saithe (Pollachius virens) Fillets

Fish gelatine and protein solutions prepared from saithe by-products were injected into saithe fillets. Effects on weight changes, water holding capacity, and chemical composition of the fillets were investigated after chilled (2, 5, and 7 days) and frozen (14 and 49 days) storage. The results showed that higher weight yields were obtained by adding proteins and salt to the fillets in comparison with only salt, especially in chilled fillets. The drawback of the injection was that higher drip losses were found during storage and thawing than for untreated fillets. Effects of injection on water content were only significant after 2 days of chilled storage, but differences leveled out after longer storage time and with freezing and thawing of the fillets. The procedure applied in this study seems to be promising for utilization of by-products such as trimmings as an ingredient in higher value products like fillets, in comparison to mince products.     

Evaluating the impact of moulting and chilled storage of spermatophores on the integrity of plasma membrane,acrosome and DNA of black tiger prawn (Penaeus monodon) spermatozoa

To explore the impact of moulting and short‐term chilled storage of spermatophores on the sperm quality for a commercially important penaeid prawn, spermatozoa of Penaeus monodon from early (B‐C), middle (D0‐1) and late (D2‐3) moult stages were compared for sperm quality parameters relating to the structural integrity of plasma membrane (Viab%), acrosome (AR%) and DNA (SDF%) after being stored at 4°C for 0–26 days. The three different sperm extenders used for chilled storage included artificial lobster haemolymph (AH), calcium free saline (CS) and filtered seawater (FS); two storage conditions were applied either as a free sperm suspension or retained within the intact spermatophore. Results showed that (a) the lowest natural AR% was shown for B‐C spermatozoa in CS whereas the highest levels were for B‐C, D0‐1 and D2‐3 spermatozoa in FS and D2‐3 spermatozoa in AH; (b) the calcium ionophore A23187 agent used in this study was able to increase the mean AR% by 6.22%; (c) the Viab% was significantly lower in CS than that in FS; (d) the SDF% significantly increased over the period of chilled storage for B‐C and D0‐1 spermatozoa, while the SDF% of D2‐3 spermatozoa was initially elevated and did not change significantly over time; and (e) there was no difference in sperm quality between two storage conditions. This study has successfully demonstrated the moult‐related variance in the percentages of acrosome‐reacted and DNA‐damaged spermatozoa, providing evidence of moult‐related spermatophore renewal cycle in this species.     

Restructured Gel Products from Farmed Meagre (Argyrosomus regius) Muscle: Effect of Low Salt Levels,Psyllium Fiber,and Chilled Storage

New heat-induced gel products prepared from farmed meagre (Argyrosomus regius) and psyllium dietary fiber (DF; up to 4.0%, w/w) with reduced salt content (from 2.5 to 1.0%, w/w) were studied. The effect of chilled storage time (15 days vs. 1 day) was also measured. Psyllium DF worsened breaking force and deformation as well as springiness, but it did not affect the remaining textural properties and improved water holding capacity (WHC). Salt reduction from 2.5 to 1.0% (w/w) decreased breaking force and deformation, cohesiveness, and WHC. The textural, color, and WHC properties of heat-induced meagre gels were unaffected by chilled storage time. Results pointed to the feasibility of using psyllium DF addition up to 4.0% (w/w) as a strategy not only to improve nutritional value of the gel products, but also to countervail some of the negative effects of a lower salt content.     

Field evaluation of live chilling with CO2 on stunning Atlantic salmon (Salmo salar) and the subsequent effect on quality

Atlantic salmon were slaughtered in three ways on a commercial slaughter line: (1) killed by a percussive stun after crowding; (2) killed by percussive stun after crowding, pumping and live chilling; (3) killed by exsanguination after crowding, pumping and live chilling. The live‐chilled fish were exposed to seawater (2°C) saturated with carbon dioxide (pH 5.5–5.7) for 40 min. The fish were calm after live chilling, but not unconscious, as eye rolling was observed in all individuals. Subsequent exsanguination of the unstunned fish resulted in death. Both rapid live chilling and the subsequent exsanguination appeared stressful to the fish, as a large and rapid pH drop coupled with earlier onset of rigor mortis, indicative of high muscle activity during the process were observed. The muscle core temperature during ice storage showed that live chilling only has an effect on carcass temperature during the first 6 h post mortem. After 6 h, no significant differences in temperature were detected between live‐chilled and traditionally ice‐chilled fish. We conclude that commercial use of live chilling in combination with high levels of CO₂ does not stun Atlantic salmon. Live chilling followed by exsanguination of the unstunned fish appears to be highly stressful and should be avoided.     

Solubilization of type I and V collagens in Japanese flounder muscle during chilled storage

ABSTRACT:   The post-mortem changes of type I and V collagens in Japanese flounder muscle during chilled storage were examined. The muscle softened significantly within 12 h under chilled storage. Both type I and V collagens isolated by ion-exchange chromatographies showed no remarkable changes in band patterns even after 24 h of storage, suggesting that degraded collagen molecules may be removed from the collagen fraction by a conventional preparation method. In contrast, type I and V collagen molecules were detected by Western blotting with each specific antibody in a saline extract and gradually increased during chilled storage. These results suggest that both type I and V collagens may participate in the post-mortem softening of fish muscle.     

The inhibitory activities and antiviral mechanism of Viola philippica aqueous extracts against grouper iridovirus infection in vitro and in vivo

Grouper iridovirus (GIV) is one of the most serious pathogens in mariculture and causes high mortality rates in cultured groupers; then, effective medicines for controlling GIV infections are urgently needed. Viola philippica is a well‐known medicinal plant, and the application of V. philippica aqueous extracts against GIV infection was assessed by different methods in this study. The results showed that the working concentration of V. philippica aqueous extracts was 10 mg/ml. V. philippica aqueous extracts below 10 mg/ml have no significant cytotoxic effects on cell viability, while extracts over 15 mg/ml decreased cell viability and showed cytotoxic activity. V. philippica aqueous extracts had excellent inhibitory effects against GIV infection in vitro and in vivo. The possible antiviral mechanism of V. philippica was further analysed, which indicated that V. philippica did no damages to GIV particles, but it could disturb GIV binding, entry and replication in host cells. V. philippica had the best inhibitory effects against GIV during viral infection stage of binding and replication in host cells. Overall, the results suggest that appropriate concentration of V. philippica aqueous extracts has great antiviral effects, making it an interesting candidate for developing effective medicines for preventing and controlling GIV infection in farmed groupers.