The Influence of Sexual Maturity,Sex and Size on Quality Aspects of Frozen Argentine Hake (Merluccius hubbsi)

The Argentine hake (Merluccius hubbsi) shows a seasonal variation in its biological condition. Results of seasonal differences in gonad maturation and spawning as well as the effect on commercialization have been reported. Considering that some technological aspects and the quality of the frozen final product are dependant on the quality of raw material, the purpose of the work was to determine the influence of sexual maturity, and other biological characteristics (sex and size) of the fish on the quality of frozen Argentine hake. Quality of fish was evaluated by determination of: Total volatile bases content (TVB), Dimethylamine nitrogen content (DMA), Formaldehyde content (FA), Salt soluble protein (SSP), Drip and Sensory evaluation. Comparisons of the experimental results between the different lots studied show that contents of FA, DMA, SSP and Drip were affected by sex, size and sexual maturity. TVB content was not affected by any of the aforementioned biological factors.     

Correlation of Kudoa Spore Counts with Proteolytic Activity and Texture of Fish Mince from Pacific Hake (Merluccius productus)

ABSTRACT

Sixteen batches of fish mince prepared using fillets from Pacific hake (Merluccius productus) harvested near Vancouver Island, Canada were studied for possible correlations of Kudoa spore counts with proteolytic activity and cooked texture. The fish were mainly infected by K. paniformis, and Kudoa spores were distributed throughout 7 sampling sites on 13 individual hake fish tested. Proteolytic activity of fish homogenate was optimum within the range of pH 5.25–5.50 and 52–55°C. Significant (p < 0.05) correlations were observed among fish mince K. paniformis spore counts, endogenous proteolytic activity, cooked texture measured as maximum compression force (g), and the change in free amino groups during autolysis.     

Influence of the Reproductive Cycle of Argentinian Hake (Merluccius hubbsi) on Fillet Yield and Operating Costs

Seasonal variations in gonadosomatic index (GSI), in the liver-somatic index (LSI), and in fillet yield of mature hake (Merluccius hubbsi) were investigated. A resting or slow recuperation period and another one of rapid transformation (October-February) were observed in gonads of female hakes. The latter occurred earlier in male fish than in female ones. Spawning took place in March. High LSI values were found after spawning and during the gonadal resting period. Low LSI values together with high GSI values were observed. For the hake filleting operation, yield of weight profile was very similar to that of LSI. A linear correlation was obtained when LSI values were plotted against fillet yield (r² = 0.818, P < 0.001). The unit cost, as well as the yield, can be linearly correlated with the LSI. This equation allows estimation of the production cost when raw material of equal initial quality in different seasons of the year is processed. The results presented are useful for inventory policies in fish plants.     

Quality Characteristics of High Pressure-Induced Hake (Merluccius capensis) Protein Gels with and without MTGase

The effects of microbial transglutaminase (MTGase; 0.5%, w/w) and high hydrostatic pressure (HHP) on the quality of protein gels from unwashed mince of hake (Merluccius capensis) trimmings were studied. MTGase incorporation improved texture. Protein solubility was lower for those gels containing MTGase, as a result of myosin heavy chain cross-linking. HHP improved texture. Pressure level was the most important HHP parameter, since higher levels (300 vs. 100 MPa) augmented gel strength (GS). A positive synergistic effect of MTGase and HHP was found for some properties, such as GS, yielding improved gels from a raw material that otherwise shows poor gelation.     

Changes During Chilled Storage of Whole Tilapia and Short-Term Frozen Storage of Tilapia Fillets

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.     

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.     

基于最大熵模型分析西南大西洋阿根廷滑柔鱼栖息地分布

根据2008—2010年中国鱿钓船在西南大西洋海域得到的生产数据及海洋环境数据(海表面温度,sea surface temperature,SST;海面高度sea surface height,SSH;叶绿素-a浓度,chlorophyll-a,chl.a),利用最大熵模型(Max Ent)分析捕捞主渔汛期间(1—4月)阿根廷滑柔鱼的潜在栖息地分布,同时与实际作业位置相比较,结合海洋环境因子分析不同年份分布差异的原因。模型运算结果显示:阿根廷滑柔鱼潜在分布区域的变化与实际作业位置变动基本一致;南北方向上,2008年和2009年的潜在分布区域较为广泛,而2010年的潜在分布区域较为狭窄,且主要分布在45°S以南的区域。Jackknife检验表明,SST是影响阿根廷滑柔鱼分布的首要环境因子,SST等温线分布可用来表征海流的强弱进而影响阿根廷滑柔鱼的分布,其中12°C等温线可以作为寻找渔场的一个指标。SSH等高线分布及其涡的变化也会影响到阿根廷滑柔鱼分布。chl.a只能间接地反映阿根廷滑柔鱼渔场的分布,不能很好地作为表征其分布的环境因子。研究表明,分析阿根廷滑柔鱼栖息地分布及其差异原因应主要观察SST和SSH的变化。     

Muscle Quality and Proteolytic Enzymes of Farmed Atlantic Cod (Gadus morhua) During Storage: Effects of Pre-Slaughter Handling and Increased Storage Temperature

ABSTRACT

In the present experiment, the characteristics of minimally handled, directly slaughtered farmed Atlantic cod were compared to cod subjected to 2 h preslaughter handling stress. The results strongly indicate that increasing the storage temperature from 0 to 5°C had a larger negative impact on the quality characteristics than the handling stress applied. Further, there may be interaction effects between handling, storage temperature, and storage time.     

Effects of Modified Atmospheric Packaging Conditions on the Quality Changes of Pasteurized Oyster (Crassostrea belcheri) Meat during Chilled Storage

ABSTRACT

The effects of different atmospheric conditions on the quality and the shelf life of pasteurized oyster meat in chilled storage were investigated. The alternatives tested for pasteurized oyster meat were normal air (Control), 75% CO₂/25% N₂ (MAP-1), 75% CO₂/25% O₂ (MAP-2), 75% CO₂/5% O₂/20% N₂ (MAP-3), and vacuum packing (VP). The various observations of microbiological (total viable count (TVC), Enterobacteriaceae, Pseudomonas spp., lactic acid bacteria (LAB), and hydrogen sulfide–producing bacteria), physical (color coordinates L*, a*, and b*, and cutting strength), chemical (moisture, pH, total volatile basic nitrogen (TVB-N), peroxide value (PV), and thiobarbituric acid reactive substances (TBARS)) and sensory properties were performed every 3 days over a total of 27 days. During storage across all the treatments, L*, a*, cutting strength, pH, moisture content, and sensory scores decreased; whereas, b*, TVB-N, PV, TBARS, and microorganisms increased. However, among the various alternatives, MAP-1 had the best retention of oyster quality during storage. Based on sensory and microbiological qualities, the shelf lives in chilled storage were 9 days for control, 15 days for VP, 21 days for MAP-2 and MAP-3, and 24 days for MAP-1-treated cases.     

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.     

Development of Quality Index Method Scheme for Common Carp (Cyprinus carpio) Stored in Ice: Shelf-Life Assessment by Physicochemical,Microbiological, and Sensory Quality Indices

ABSTRACT

Sensory methods are the most interesting methods to estimate fish quality. Among these, the recently developed quality index method (QIM) has gained popularity, as shown by the multiple publications of QIM schemes in the last years. The objective of this study was to create a new QIM scheme (QIM sensory table and corresponding point system) for the common carp (Cyprinus carpio), basing the definition of the rejection point on sensory, physicochemical (thiobarbituric acid reactive substances, total volatile basic nitrogen, pH, and color measurements), and microbiological criteria (counts of mesophiles, psychrotrophs, and Pseudomonas spp.). A new QIM scheme was developed and is proposed for use in the future; it will be useful for practical evaluations of carp freshness in all steps of the production chain, and it will contribute to a more effective use of the species as an alternative for human food supply.     

Influence of size, age and maternal condition on the oocyte dry weight of Argentine hake (Merluccius hubbsi)

Effects of maternal age–size and condition on oocyte dry weight were analysed for Merluccius hubbsi. Samples of mature females were collected in the Patagonian spawning area during 10 research surveys carried out between 2000 and 2005. Dry weight of 50 hydrated oocytes ranged from 0.80 to 1.90 mg. Relationships of this variable with total length and age were best described by a logarithmic model during the spawning peak. At the beginning and at the end of the reproductive season no significant relationship between these variables was observed, but a decrease in egg dry weight was detected during the spawning period. In general, young spawners (≤5-year-old) showed more variability in egg dry weight, which was associated with a reproductive season shorter than that of old females. Relative condition factor did not shows a significant relationship with oocyte dry weight, and mean values of this index were similar for different months of the spawning seasons analysed.     

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.     

Sensory Quality and Shelf Life of MAP Redfish (Sebastes marinus) Fillets as Affected by Previous MA Bulk Storage of Whole Fish

Abstract

The shelf life of iced redfish is known to be 16–19 days. This study evaluated the effects of modified atmosphere (CO₂/N₂: 60/40) in bulk storage of redfish and subsequent modified atmosphere packaging (MAP) of fillets. Fish were evaluated by sensory, microbiological and chemical methods. Modified atmosphere (MA) bulk storage of whole fish for more than 5 to 10 days did not improve their sensory quality or significantly increase shelf life. In fact, the study showed negative effects in texture and overall appearance. MAP of fillets processed from 10-day MA bulk stored fish showed a modest increase in shelf life, but negatively affected their texture. Sensory qualities, i.e., tenderness, that decreased under MA bulk storage were improved upon aerobic storage for fish stored under MA for 5 to 10 days, but not 14 days. Lower microbial levels were found in MA bulk stored fish and MAP fillets compared to traditionally iced fish, while higher TMA levels were found in MAP fillets.     

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.     

Formation of Biogenic Amines and Associated Biochemical and Microbial Attributes of Whole Sutchi Catfish (Pangasianodon hypophthalmus) during Iced Storage

Sutchi catfish (Pangasianodon hypophthalmus) is a highly preferred farmed species that is produced in huge quantities. Meat from ice-stored (4 ± 2°C) whole Sutchi catfish was evaluated for formation of biogenic amines, such as putrescine, cadaverine, histamine (HIM), agmatine, tyramine, spermine, and spermidine, and compared with biochemical, microbial, and sensory attributes during 22 days. Analysis of content of biogenic amines in the meat was carried out by liquid chromatography with tandem mass spectrometry using a without derivatization method. Three amines, namely, tyramine, spermidine, and spermine, were only present on 0^th day of storage. Presence of cadaverine was noticed from 9^th day onwards, where the aerobic plate count (APC) reached 4.85 log CFU/g. Putrescine was detected on the 22^nd day of storage, where the APC crossed 7 log CFU/g. HIM was detected in lower quantities from 3^rd day onwards. A shelf life of 15 days was determined based on sensory and microbiological evaluation. Although the samples were biochemically acceptable throughout the storage period, APC exceeded the limit on day 19, and the gradual increase of H₂S-producing bacteria, Brochothrix thermosphacta, Aeromonas, and Enterobacteriaceae, was observed during storage.     

A Comparative Study on the Quality Changes of Croaker (Johnius dussumieri) Fish Stored in Slurry Ice and Flake Ice

In the present study, the effect of storage in slurry ice compared to conventional flake ice (control) on the quality of croaker (Johnius dussumieri) fish was evaluated. Biochemical, microbiological, and sensory analyses were performed. Total volatile base nitrogen, trimethylamine nitrogen, and pH values were lower for fish stored in slurry ice than in control. Similarly, aerobic plate count and Pseudomonas sp. count were also found at lower population levels in fish stored in slurry ice. Texture profile analysis revealed that fish stored in slurry ice showed improved texture. Based on the microbiological and sensory analysis, the shelf life of croaker fish stored in slurry ice was 15 days.     

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.