Effect of ice storage on the functional properties of pink perch and oil sardine meat

Ice storage of dressed pink perch (Nemipterus japonicus) and Indian oil sardine (Sardinella longiceps) for 16 and 20 days, respectively, resulted in a decrease in emulsifying capacity (EC), protein solubility (PS), relative viscosity (RV) of salt‐soluble proteins (SSP) and water‐soluble proteins (WSP), water binding capacity (WBC) in terms of absorbed moisture in water (AM_w), absorbed moisture in brine lpar;AM_b), retained moisture in water (RM_w) and retained moisture in brine (RM_b), WSP and SSP, and increase in cook loss (CL). Decrease in protein solubility influenced the EC, RV, CL and WBC in both the species of fish. Significant (P<0.05) correlations existed among various functional properties analysed, in both the fishes during the ice storage. © 1999 Society of Chemical Industry     

Influence of feeding state and frozen storage temperature on the lipid stability of Atlantic mackerel (Scomber scombrus)

Lipid deterioration of mackerel caught in Icelandic waters was studied, as affected by different frozen storage temperatures (?18 °C vs. ?25 °C) and seasonal variation (August vs. September). The lipid stability was investigated by analyses of hydroperoxide value (PV), thiobarbituric acid reactive substances (TBARS), free fatty acids, as well as changes in fatty acid composition. Results showed significant lipid deterioration with extended storage time, where the lower storage temperature showed significantly more protective effects. Furthermore, a higher lipid oxidation level was recorded for fish caught in September than in August, although lipid hydrolysis occurred to be greater for fish in August than in September. Moreover, results indicated a rather stable level of omega‐3 fatty acid during the whole frozen storage period. The analysis indicated that both lipid oxidation and hydrolysis were affected by the frozen storage temperature and the stability differed with regard to season of catch.     

The effect of frozen storage of mackerel (Scomber scombrus) on its quality when hot-smoked

Whole mackerel (Scomber scombrus) were frozen using a horizontal plate freezer, wrapped in plastic bags and frozen stored at - 20°C. At suitable intervals (11, 22 and 33 weeks) the fish were removed from the cold store and subsequently hot smoked (in gutted from) using an AFOS-Torry Mini Kiln. All smoked mackerel samples, despite their different previous histories, were assessed by the panellists as moderately acceptable products in- terms of their texture and flavour, even after 33 weeks frozen storage prior to smoking. Protein denaturation, as related to salt-soluble protein, was influenced by the frozen storage history (24% drop after 33 weeks frozen storage) and seemed to be affected by the free amino acids formed during frozen storage. After smoking the denaturation was extensive (above 80%) in all mackerel samples. Lipid oxidation was quite extensive (PV 108 meq kg^?1) in the 22 and 33 weeks frozen stored mackerel samples. However, no rancid flavour in the latter smoked mackerel samples was detected by taste panellists. A 58% increase in free amino acids during frozen storage was observed. Extensive losses of 74% in available lysine were observed in the 22 and 33 weeks frozen stored mackerel samples after smoking which could be due to aminocarbonyl reactions with the products of lipid oxidation. A 40% loss of thiamine was observed in the 33 weeks frozen stored samples after smoking. The histamine contents did not exceed 94 mg kg^?1 and would not be expected to cause symptoms of scombrotoxin poisoning.     

The effects of freeze-drying and storage on the FT-Raman spectra of Atlantic mackerel (Scomber scombrus) and horse mackerel (Trachurus trachurus)

FT-Raman spectroscopy was undertaken for quantitative characterization of lipids in horse mackerel (Trachurus Trachurus) and Atlantic mackerel (Scomber scombrus). Peroxide value of fish lipids and protein extractability of the fish lipids and muscles were also measured by titration and Bradford assay, respectively.     

Use of kiam wood extract as gel enhancer for mackerel (Rastrelliger kanagurta) surimi

Kiam ( Cotylelobium lanceotatum craih) wood was extracted using water or ethanol. Water kiam wood extract (WKWE) and ethanolic kiam wood extract (EKWE) contained tannin at levels of 251.90 and 456.30 mg g⁻¹ of dry extract, respectively. Effects of WKWE and EKWE at different levels (0–0.60% of protein content) on the properties of gels from mackerel ( Rastrelliger kanagurta ) surimi were investigated in comparison with commercial tannin (CT). Gels added with 0.30% WKWE, 0.15% EKWE or 0.30% CT had the increases in breaking force by 134.81%, 136.09% and 121.34% and in deformation by 52.60%, 54.96% and 33.53%, respectively, compared with the control (without addition of extracts or CT). The lowered expressible moisture content and the formation of cross-linked myosin heavy chain were also observed in surimi gels incorporated with those additives. Thus, the extract of kiam wood can be used as surimi gel enhancer without affecting its sensory properties.     

Chemical and nutritional quality of Indonesian dried-salted mackerel (Rastrelliger kanagurta)

Indonesian mackerel ( Rastrelliger kanagurta ) were sun dried or salted and sun dried and stored at 30°C for up to 20 weeks in air. During processing and storage polyunsaturated fatty acids oxidized to form thiobarbituric acid (TBA) reactive substances and fluorescent compounds. TBA values increased with increasing salt content (range 2.3–20.7%). Positive, highly significant correlations were found between the odour of the stored products and both fluorescent pigment production and the degree of browning. Amino acid analysis indicated loss of lysine, glutamic acid, serine, histidine, arginine and the sulphur containing amino acids, but these losses were far too small to account for the massive decreases found in net protein utilization (NPU) of the stored products, measured by rat-feeding trials. The latter were highly correlated with the fluorescent pigment content and degree of browning in products of intermediate (∼ 14%) salt content.     

The effect of different salting procedures and qualities of raw material on some nutrients during processing and storage of salted-dried mackerel

Salted-dried mackerel ( Scomber scombrus ) was prepared using fresh fish or fish which had been stored in ice for 75h and four methods of salting, namely 15% brine, saturated brine, pickle and dry salting. Samples were analysed for available lysine, thiamine and riboflavin before salting, after salting, after drying and after 1 month's storage at 20°C. Final losses of each of these nutrients were lowest when the fish were pickle cured. Losses were also lower when fresher raw material was used. the use of good quality fish and a pickle salting method is therefore recommended for this type of product.     

Preliminary development of intermediate moisture,pasteurised mackerel (scomber japonicus marplantensis) chunks

The objective of this study was to develop an intermediate moisture, pasteurised mackerel product combining the lowering of water activity (a_w) by means of selected solutes with pasteurisation. Loss of water was achieved by soaking in an equilibrium solution containing glycerol, salt, and potassium sorbate. An optimum cooking time of 20 min in the infusion solution and an optimum immersion time of 20 h in the same solution were determined. A final a_w value of 0.89 was obtained. These parameters were selected taking into account the sensory assessment, since the main problem in this kind of food is acceptance by the consumer. The product was pasteurised at 90°C for 40 min. The product obtained by this combination of conditions had a moderately sweet taste and a succulent texture.     

Effect of different thawing methods on the quality of mackerel (Pneumatophorus japonicus)

Food Science and Biotechnology - Five thawing methods such as flow water thawing, ultrasonic flowing water thawing, air thawing, microwave thawing and low temperature thawing were used, and the...     

Effect of frozen-storage period on quality of American sirloin and mackerel (Scomber japonicus)

Food Science and Biotechnology - This study aimed to study the effect of frozen-storage period on the quality of sirloin and mackerel (Scomber japonicus). The samples were evaluated after being...     

Non-dioxin like polychlorinated biphenyls in mackerel (Scomber scombrus) available on the Serbian market

Mackerel is rich in omega-3 fatty acids, but this fish may be contaminated with environmental pollutants. The aim of this study was to evaluate concentrations of non-dioxin like polychlorinated biphenyls (ndl-PCBs) in 160 samples of mackerel available on the Serbian market. Average and maximum ndl-PCB concentrations were 7.9 ng/g and 74 ng/g, respectively. A higher average level of ndl-PCBs was found in mackerel from Spain, but this was still three times lower than the permitted level. We conclude that levels of ndl-PCBs in mackerel available on the Serbian market are acceptable.     

Characterisation of the microbiota of Atlantic mackerel (Scomber scombrus)

In this study the microbiota of Atlantic mackerel (Scomber scombrus) collected by a commercial purse seiner was examined. Fish were collected directly from the purse seine and from the Refrigerated Sea Water (RSW) transport tank after loading. The culturable microbiota and Specific Spoilage Bacteria (SSB) were quantified on Iron Agar Lyngby (IAL) and identified using commercially available Biochemical API® kits on pure cultured isolates. These kits showed to be sub-optimal in characterising the isolates, since only half of the strains were identified. The same isolates were also identified by a nucleic acid based PCR-DGGE approach, and only half of the sequences gave the same results as the API®. Characterisation by PCR-DGGE was also performed on bacterial DNA from IAL plates (bulk cell samples) and on samples where the bacterial DNA was extracted directly from fish material without any cultivation (direct DNA samples). The microbiota of Atlantic mackerel was dominated by members of the Gram-negative genera as Psychrobacter sp., Proteus sp., Photobacterium sp., Vibrio sp., Shewanella sp., Synechococcus sp., Oceanisphaerae sp., Bizonia sp., Pseudoalteromonas sp., and members of Flavobacteriaceae. Gram-positive bacteria in the genera Vagococcus sp., Bacillus sp., Mycobacterium sp., Staphylococcus sp., Mycoplasma sp. and Clostridia sp. were also found. Examination by PCR-DGGE and sequencing of the bulk cell pellet after cultivation on IAL, gave a higher number of taxa as compared to extraction and examination of bacterial DNA from fish materials without prior cultivation. This shows the benefit of combining both culture dependent and culture independent methods, when studying the microbiota of marine fish. Several Vibrio spp. were found only in gut samples collected from the purse seine, but in all samples including the skin and the gills collected from the RSW tank, indicating microbial contamination by faecal bacteria from the fish under these transport conditions.     

Sensory and microbiological assessment of irradiated bluejack mackerel (Trachurus picturatus)

Bluejack mackerel caught off the Portuguese coast were irradiated with pasteurising doses of 1, 2 and 3 kGy using a ⁶⁰Co gamma source; they were compared with a non-irradiated control sample for external appearance in the raw fish and for texture, flavour, odour, humidity and colour in the cooked muscle, by a group of experienced panellists. Differences were found between the control and the irradiated samples but not among them. An extension of two to three times the shelf-life was obtained.     

Physical measurement of the quality of fresh scad (Trachurus trachurus) and rainbow trout (Oncorhynchus mykiss) during ice storage using the RT Freshmeter

The RT Freshmeter was used to obtain a quality index of two Portuguese fish, scad ( Trachurus trachurus ) and farmed rainbow trout ( Oncorhynchus mykiss ). The curves obtained were comparable to those previously published using the GR Torrymeter. However variations were lower during the first phase of storage and it was observed that the curves could be divided into two distinct regions. The slope of the linear regression was higher during the first 5 days of storage, representing the first region of the curve, in both fish studied.
It is proposed that the two different rates of change of the quality index obtained with the meter reflect the two predominant spoilage mechanisms, enzymic and microbiological. The RT Freshmeter measurements are compared to organoleptic changes.
Preliminary results obtained with the RT Freshmeter on rainbow trout fillets without skin indicate that this instrument is not suitable for use with this product due to large variations and curve slopes close to zero.     

Partial replacement of NaCl by KCl in salted mackerel (Scomber japonicus) fillet products: effect on sensory acceptance and lipid oxidation

Mackerel fillets were salted with NaCl and/or KCl to determine the most acceptable level by sensory evaluation. Additionally, the effects of ascorbic acid, vacuum packaging, and cold storages on lipid oxidation were determined for the salted mackerel fillets. Appropriate level of NaCl was ≤2%. Fifty percent replacement of NaCl by KCl reduced NaCl level with minimal impact on sensory quality. The higher the level of ascorbic acid (0–0.5%, weight basis), the higher the antioxidant effect observed with thiobarbituric acid value and peroxide value. There was no significant difference in sourness (α = 0.05) between the salted mackerel samples treated with and without ascorbic acid (0.25%). Vacuum packaging and storage at ?18 °C along with ascorbic acid was most effective in retarding lipid oxidation in the salted mackerel. Vacuum‐packaged sample with ascorbic acid stored at 2 °C was least oxidised, followed by vacuum packaging without ascorbic acid and then ascorbic acid without vacuum.     

包装对低温贮藏盐水鸡产品货架期及优势污染菌群的影响

盐水鸡是一种具有客家风味的传统鸡肉制品。为寻找一种能经济、有效地延长冷链销售盐水鸡货架期的包装方式,本文比较了普通包装、真空包装和气调包装对盐水鸡产品理化指标和优势污染菌群的影响。研究结果表明,盐水鸡在低温贮藏期间,各种包装对盐水鸡的含水量、pH和挥发性盐基态氮的影响不显著(p>0.01);在低温贮藏期间,各种包装中好氧性菌落总数呈线性增长,其增长速率为普通包装>气调包装>真空包装。在整个短期低温贮藏期间,没有在各种包装的盐水鸡样品中检测出产气芽孢梭菌,大肠菌群及乳酸菌,但能检测出少量的霉菌和酵母。采用16srDNA序列分析法对各种包装中污染的优势好氧性菌落进行了分类鉴定。鉴定结果表明,各种包装中的优势好氧性菌有Pseudomonas sp., Staphyloccocus aureus,Exiguobacterium sp.,和Carnobacterium sp.,且各种包装中优势菌群存在明显差异。     

包装与温度对欧芹贮藏效果的影响

研究了不同贮藏温度(常温、0℃)和包装(20μm、30μm和60μmPE膜)条件下欧芹枝叶Vc、叶绿素和类胡萝卜素含量以及失重率、含水量变化情况。结果表明:随着贮期的延长,欧芹失重率增加,Vc、叶绿素和类胡萝卜素含量逐渐减少。低温和包装能够显著抑制水分蒸发,保持较高的Vc、叶绿素和类胡萝卜素含量,30μmPE包装较20μm和60μm贮藏效果好。     

Proteolytic processing of Atlantic mackerel (Scomber scombrus) and biochemical characterisation of hydrolysates

Research on fish composition has demonstrated that they constitute a promising source of molecules with health benefits. In the present study, Atlantic mackerel ( Scomber scombrus ) was processed using Protamex® and the distribution of nutrients in various fractions obtained following membrane filtration was analysed. The fish starting material was approximately 84% water and the dry matter contained 42.7% proteins, 45.2% lipids and 5.6% minerals. The recovery of fish dry matter in the liquid hydrolysate was 77.8%. Most of the fractions were protein-enriched and characterised by a well-balanced amino acid composition, notably in terms of the most essential amino acids and by molecules of relatively low molecular weight (≤42 kDa). Even before process optimising, the biochemical and nutritional analyses indicate that the Atlantic mackerel may provide high-value products for future applications in the health and food sectors.     

Effect of Film-Forming Gums in the Preservation of Salted and Dried Indian Mackerel (Rastrelliger kanagurta Cuvier)

Curing preservation of fish is the most popular method in the developing countries and India is no exception. Different film-forming gums, namely sodium alginate, tamarind kernel powder, guar gum and agar agar were tried to find their effect in preservation of salted and dried mackerel and in extending the shelf-life of these products. Various biochemical, microbiological and organoleptic parameters were recorded during the storage period. The treatment of salted dried fish with gum solutions and subsequent formation of film upon drying was found to be the best in preserving the quality of salted fish. The effect of film forming gums on the shelf-life of the products was found to be highly significant ( P< 0·05) as compared to the control.