Effect of frozen storage on the quality of whole fish and fillets of horse mackerel (Trachurus trachurus) and mediterranean hake (Merluccius mediterraneus)

 Whole fish and fillets of horse mackerel (Trachurus trachurus) and mediterranean hake (Merluccius mediterraneus) were assessed for quality (physical, chemical and sensory attributes) changes throughout 12 months of frozen storage at −18 °C. The pH, expressible water (EXW), quantities of trimethylamine (TMA), dimethylamine (DMA), formaldehyde (FA), the total volatile base nitrogen (TVB-N) the thiobarbituric acid number (TBA), peroxide value (PV) and amount of free fatty acids (FFA) increased, while sensory attributes (odour, taste, texture) decreased during the frozen storage period. A comparison of quality scores between whole fish and fillets of horse mackerel and mediterranean hake showed that there were no significant differences (P>0.05) in attribute scores. There were, however, significant differences (P<0.05) in pH, EXW, TMA, DMA, FA, TVB-N, TBA, FFA and PV. Received: 19 April 1996/Revised version: 7 September 1996     

Effect of delayed icing on quality changes of iced rainbow trout (Onchorynchus mykiss)

The effect of delayed icing on quality deterioration of rainbow trout (Onchorynchus mykiss) iced 0, 4 and 8 h after catch was assessed by chemical, microbiological and sensory methods. Total volatile basic nitrogen (TVB-N), free fatty acids (FFA), peroxide value (PV) and thiobarbituric acid (TBA) values increased during the pre-icing duration. Delayed icing led to significant increased (p < 0.05) in total viable counts (TVC) throughout the period of storage. This study showed that sensory analysis of rainbow trout correlated well with microbiological analysis. Results of this study according microbiological and sensory data indicated that the shelf-life of rainbow trout stored in ice immediately after catch was approximately 9–11 days, while delay in icing for 4 and 8 h shortened the shelf-life was around 5–7 and 1–3 days, respectively.     

暗纹东方不同贮藏温度货架期模型的预测研究

为了研究河豚鱼在冷链流通中的品质变化与货架期,通过不同温度下的贮藏实验研究了河豚鱼的货架期预测模型。将河豚鱼贮藏在273、277和281K条件下,测定了河豚鱼的总菌落数、总挥发性盐基氮(TVB-N)、脂肪氧化(TBA)值和三甲胺值的变化。在Arrhenius动力学方程基础之上,建立了菌落总数、挥发性盐基氮、脂肪氧化(TBA)值和三甲胺值与贮藏时间及贮藏温度之间的动力学模型。实验表明一级化学反应动力学模型和Arrhenius方程对菌落总数、挥发性盐基氮(TVB-N)、脂肪氧化(TBA)值及三甲胺值的变化具有较高的拟合精度。各项指标(菌落总数、挥发性盐基氮、TBA值以及三甲胺)变化预测模型中的活化能(EA)及速率常数(k0)分别为:21.10kJ/mol和1.059×103,76.58kJ/mol和2.888×1013,6.59kJ/mol和4.012,18.35kJ/mol和1.393×103。结果表明:河豚鱼的总菌落数、挥发性盐基氮(TVB-N)、脂肪氧化(TBA)值及三甲胺值随着贮藏时间的延长而增加,且随着贮藏温度的升高而迅速增加。该实验建立的河豚鱼货架期预测模型所获得货架期预测值准确率达到±10%以内,可根据菌落总数和TVB-N值在273～281K范围内,对河豚鱼的剩余货架期进行预测。     

Effect of essential oils treatment on the frozen storage stability of chub mackerel fillets

The effect of bay leaf (BLO), thyme (TO), rosemary (RO), black seed (BSO), sage (SO), grape seed (GSO), flaxseed (FSO) and lemon (LO) essential oil from vegetable extracted on lipid oxidation and some other quality parameter of frozen chub mackerel during frozen storage at ?20°C were examined over a period of 11 months. Taste, odour, texture and overall acceptability of control samples were given ‘unacceptable’ scores by the sixth month. Based primarily on sensory data, the shelf-lives of frozen chub mackerel were found 6 month for samples treated with oil of TO, RO, BSO, SO and LO and 7 month for samples treated with BLO, GSO and FSO. During the 11-months storing process of chub mackerel, the values of pH, total volatile basic nitrogen (TVB-N), trimethylamine nitrogen (TMA-N) both in control group samples and samples treated with oils did not reach to deterioration levels. Thiobarbitüric acid (TBA) and free fatty acid (FFA) values for all treatments remained lower than TBA and FFA values of control samples throughout the 11 month storage period. Particularly, thyme oil treatment is effective in delaying lipid oxidation. Bay leaf, rosemary, sage, lemon, flaxseed and grape seed oils were fallowed.     

不同温度冻藏对军曹鱼片品质的影响

研究不同冻藏温度(－ 10、－ 18、－ 30℃)对军曹鱼片部分理化指标、质构特性及感官品质的影响。结果表明,冻藏温度对军曹鱼片的解冻汁液流失率、蒸煮损失率、盐溶蛋白含量、Ca2+-ATPase 活性和TBA 值(硫代巴比妥酸)均有显著性影响(P ＜ 0.05)。冻藏时间越长、冻藏温度越高,汁液流失率、蒸煮损失率、TBA 值增加越大,盐溶蛋白含量、Ca2+-ATPase 活性下降也越多,即保水性降低、蛋白质变性程度增大、脂肪氧化加快。TPA(质构分析)发现军曹鱼片的硬度和耐嚼性随着冻藏时间的延长均呈显著增加趋势(P ＜ 0.05),而回复性则显著下降(P ＜ 0.05);冻藏温度越低,相应的硬度和耐嚼性就越小,而回复性则越大。感官评价表明冻藏导致军曹鱼片的品质下降,冻藏温度越高,品质劣变就越严重。采用较低的温度(－ 30℃)冻藏可以最大限度的保持军曹鱼片的品质。     

Effect of essential oils treatment on the frozen storage stability of chub mackerel fillets

The effect of bay leaf (BLO), thyme (TO), rosemary (RO), black seed (BSO), sage (SO), grape seed (GSO), flaxseed (FSO) and lemon (LO) essential oil from vegetable extracted on lipid oxidation and some other quality parameter of frozen chub mackerel during frozen storage at −20°C were examined over a period of 11 months. Taste, odour, texture and overall acceptability of control samples were given ‘unacceptable’ scores by the sixth month. Based primarily on sensory data, the shelf-lives of frozen chub mackerel were found 6 month for samples treated with oil of TO, RO, BSO, SO and LO and 7 month for samples treated with BLO, GSO and FSO. During the 11-months storing process of chub mackerel, the values of pH, total volatile basic nitrogen (TVB-N), trimethylamine nitrogen (TMA-N) both in control group samples and samples treated with oils did not reach to deterioration levels. Thiobarbitüric acid (TBA) and free fatty acid (FFA) values for all treatments remained lower than TBA and FFA values of control samples throughout the 11 month storage period. Particularly, thyme oil treatment is effective in delaying lipid oxidation. Bay leaf, rosemary, sage, lemon, flaxseed and grape seed oils were fallowed.     

紫苏水提物联合蒸煮处理对脆肉鲩鱼片冻藏过程中品质的影响

为了研究蒸煮处理及紫苏水提物对脆肉鲩鱼片冻藏品质的影响,以紫苏水提物浸泡的生鱼片（生鱼片组）、紫苏水提物浸泡再进行蒸煮制备的熟鱼片（熟鱼片组）、蒸馏水浸泡的生鱼片（对照组）为研究对象,研究这3 组鱼片在冻藏过程中质构、持水性、盐溶性蛋白含量、Ca2＋-ATPase活性、硫代巴比妥酸（thiobarbituric acid,TBA）值、挥发性盐基氮（total volatile base-nitrogen,TVB-N）含量和感官评分的变化。结果表明：熟鱼片及生鱼片组通过最大冰晶生成带的时间比对照组长;与对照组和生鱼片相比,熟鱼片在冻藏过程中一直维持较高的硬度、弹性、咀嚼性、TBA值和较低的持水力、盐溶性蛋白含量、TVB-N含量;与对照组相比,生鱼片组的质构特性、持水力、盐溶性蛋白含量和Ca2＋-ATPase活力更高,而TBA值和TVB-N含量更低,冻藏300 d后,生鱼片TBA值是贮藏初始时的3.85 倍,TVB-N含量低于20 mg/100 g;感官评价结果进一步表明,3 组样品感官品质在冻藏过程中不断下降,其质地、口感以及汤汁浑浊度评分从高到低依次是熟鱼片、生鱼片和对照组。研究结果证明了紫苏水提物联合蒸煮处理更有利于冻藏过程中脆肉鲩鱼片品质的维持。     

Sensory and Chemical Evaluation of the Keeping Quality of the Brazilian Freshwater Fish Prochilodus scrofa in Ice Storage

The keeping quality of the freshwater fish Prochilodus scrofa in ice storage was investigated in two runs. Sensory evaluation of the raw fish reflected the progressive deterioration during storage. Sensory evaluation of the baked fish was less indicative of the state of freshness. None of the chemical analyses utilized (TVN, TBA, FFA, PV, qualitative tests) could be a reliable index of freshness. The keeping time was about 18 days in the first run and 12 days in the second run. Evisceration under commercial conditions did not extend the storage life.     

流化冰预冷处理对鲈鱼贮藏期间品质变化的影响

目的：模拟鲈鱼生产流通过程（即预冷、运输、贮藏环节）,以碎冰为对照,研究了流化冰预冷对新鲜 鲈鱼运输期间的控温效果与贮藏期间品质变化的影响。方法：将新鲜鲈鱼随机分组,分别进行流化冰预冷-运输-贮 藏（slurry ice,SI）、流化冰预冷-无冰运输-碎冰贮藏（slurry ice-no ice-crush ice,SNI）与碎冰预冷-运输-贮藏 （CK）3 种流通方式,在贮藏期间定期取样进行感官、理化（pH值、盐度、质构与硫代巴比妥酸值）及微生物 （菌落总数）指标测定,并结合扫描电子显微镜与聚丙烯酰胺凝胶电泳分析,综合评价其鲜度变化。结果：流化冰 在1.0～1.5 h内将鲈鱼中心温度降至0 ℃,鱼体终温为－1.1 ℃,降温速率显著高于碎冰预冷处理。在贮藏中后期, 与CK组相比,SI组能较好保持鲈鱼的感官品质和质构特性,抑制硫代巴比妥酸值、pH值与菌落总数的升高,有效 延缓蛋白质分解与肌肉组织降解速率,货架期为18 d左右,相对CK组延长了6 d。SNI组无冰运输过程中鲈鱼体温 维持在0.8 ℃以下,贮藏期间其样品质构特性、微生物生长及蛋白质降解水平与CK组差异不大,两组货架期均为 12 d;说明流化冰预冷具有较好的控温作用,能在一定程度上维持鲈鱼的鲜度。结论：流化冰是一种快速、高效的 保鲜处理方式,SNI组无冰运输操作可提高鱼样装载量,节约运输成本,因此该研究对水产品的短途运输具一定的 参考价值。     

MEASURING TEXTURAL CHANGES IN FROZEN MINCED COD FLESH

Textural deterioration in frozen cod fillet and frame minces were monitored for up to 35 days of storage at —7C and —40 C. Changes during storage were followed by measuring expressible moisture (EM), dimethylamine (DMA) production, springiness and cohesiveness with a raw texture panel, and relaxation time during a 50% compression on the Instron. Results indicate that EM, texture panel perceptions and the Instron follow changes during the early 35 days of frozen storage that occur with a different time course better than the DMA changes. The higher storage temperature showed a more rapid change in the properties measured as did the frames in comparison to the fillets.     

Preprocessing Ice Storage Effects on Functional Properties of Fish Mince Protein

Holding in ice before mincing and freezing pink perch, Nemipterus japonicus, resulted in significant differences in protein solubility (PS), emulsifying capacity (EC), water binding capacity (WBC), cook loss, thaw drip and texture scores. Functional properties correlated with protein solubility. Significant variations in PS, EC, WBC, texture scores, and thaw drip values during frozen storage suggested these properties may be valuable indicators for determining alterations in functional characteristics of fish proteins.     

Texture Changes of Frozen Stored Cod and Ocean Perch Minces

During frozen storage, minced cod and ocean perch were examined by expressible moisture (EM), water binding potential (WBP) and computerized texture profile analysis (TPA). The results suggested that a microcomputer interfaced with the Instron efficiently performed TPA. The texture and water loss of all fish minces changed more rapidly at -7°C storage than at -20°C and -40°C. Furthermore, cod, a gadoid with the ability to degrade trimethylamine oxide to dimethylamine and formaldehyde, deteriorated faster than ocean perch, which did not have this ability. EM was useful for examining the water loss of frozen fish at - 7°C only during the first two weeks of storage. The WBP at -7°C storage showed a good correlation with storage time for cod and ocean perch. This suggests that WBP might be a good indicator for examining water holding ability of fish proteins.     

STORAGE STABILITY OF COMMERCIALLY PREPARED AND FROZEN POND-RAISED CHANNEL CATFISH (Ictalurus punctauts, rafinisque)

SUMMARY –The storage stability of frozen pond-raised channel catfish from five commercial processing plants was examined. Three distinct types of processing treatment were included in the five lots. Fish samples were evaluated initially and at regular intervals during frozen storage up to 270 days. The evaluations included changes in moisture, pH, fat stability (TBA value) and shear press values of the uncooked fish, and in sensory ratings for appearance, aroma, color, texture and flavor of the cooked products. Moisture losses and changes in pH during frozen storage were not statistically significant (P = 0.05). Thiobarbituric acid (TBA) values indicative of changes in fat stability, incresed in all five lots of fish with prolonged storage but were not closely correlated with changes in flavor rating. Sensory ratings for quality of the cooked product decreased significantly with successive storage periods. The regression patterns representing changes in quality during storage varied among the different losts of fish. Certain variations were related to the processing treatments.     

Microbiological Properties and Biogenic Amines of Whole Pike‐Perch (Sander Lucioperca,Linnaeus 1758): A Perspective on Fish Safety During Postharvest Handling Practices and Frozen Storage

Abstract: The biogenic amines (tyramine, histamine, cadaverine, and puterscine) and microbiological properties (mesophilic, psychrotrophic, and Pseudomonas spp.) of whole pike‐perch (Sander lucioperca) was investigated during 2 d prestorage icing and 90 d frozen storage (−24 °C). At the end of ice storage, a noticeable increase only was found for puterscine level (P < 0.05), and microbial loads of fish increased in comparison with fresh fish (P < 0.05). During the frozen storage, as time passed, a continuous increase of biogenic amines and decrease of bacterial load (except for Pseudomonas spp. at the last 30 d) was detected (P < 0.05). The total contents of biogenic amines ranged from 6.24 to 91.76 μg/g during the investigated period. Puterscine was the major amine detected in pike‐perch and its concentration varied between 1.75 and 56.95 μg/g; due to a more step‐wise increase it was a good quality indicator. At the end of storage, all of the obtained values are below the tolerable maximum amounts based on available regulations. Based on biogenic amines content and microbial load, it could be concluded that pike‐perch can be consumed without any health risks after 2 d icing condition and 90 d frozen storage. Practical Application: Biogenic amines as one of the commonest forms of food intoxication occur in protein‐rich food such as fish. Short‐time icing during transportation is the simplest method to fish preserving for processing or long‐term storage. In this study formation of biogenic amines and bacterial changes in ungutted pike‐perch as highly demanded fish species for human consumption, during transportation and frozen storage was investigated. The results of the research can be advantageously used by fish industry. These findings suggest that the production and storage practices of fish in the retails condition could have acceptable food quality level.     

Total,non-volatile free fatty acids as a freshness index for hake (Merluccius hubbsi) stored in ice

Total, non-volatile free fatty acids (FFA) content was determined in hake muscle during fish storage in ice. FFA increased linearly in every season according to freshness loss as determined by sensory scoring. FFA determination is proposed as a valuable alternative to sensory scoring in determining fish deterioration in ice.     

Quality Assessment of Farmed Rainbow Trout (Oncorhynchus mykiss) during Chilled Storage

ABSTRACT:  The quality changes of farmed rainbow trout ( Oncorhynchus mykiss ) stored in ice for a period of up to 20 (0, 4, 8, 12, 16, and 20) d were determined by chemical (total volatile basic nitrogen [TVB-N], free fatty acid (FFA), thiobarbituric acid (TBA), peroxide value (PV), heme iron), microbiological (total viable counts, TVC), and sensory methods. The TVB-N level showed fluctuations during storage, indicating that TVB-N could not be a good indicator of rainbow trout quality. The TBA values remained low and were found to fluctuate during storage. The PV values and the release of FFA increased ( P < 0.05), while heme iron content decreased during storage. The total viable counts of rainbow trout increased ( P < 0.05) from the initial value of 4.0 log CFU/g (day 0) to 7.04 log CFU/g (day 20) over the period of storage. This study showed that sensory analysis of rainbow trout correlated well with the microbiological analysis. The results of this study according to microbiological and sensorial data indicated that the shelf life of rainbow trout stored in ice was approximately 9 to 11 d.     

竹荚鱼冻藏过程中肌肉品质与蛋白质理化性质的变化及其相关性分析

为探究竹荚鱼冻藏期间的新鲜度品质变化规律,本文以色泽、电导率、冰晶大小及形态、质构、K值、TBA值、拉曼光谱、总蛋白二级结构、肌原纤维蛋白巯基含量和Ca2+-ATPase活性等为指标,研究了真空包装（VP）和空气包装（AP）的竹荚鱼在?18 ℃冻藏90 d内的肌肉品质和肌肉蛋白质理化性质的变化。结果显示,随着冻藏时间的延长,VP、AP两组鱼肉样品的K值、L*值、白度值、TBA值均逐渐升高,其中K值冻藏90 d后分别增加了65.83%和66.44%;同时鱼肉中冰晶孔隙逐渐增大,a*值、b*值、硬度、咀嚼度、回复性则逐渐下降,内聚性和电导率呈现先升高后降低趋势。蛋白质理化测定结果显示,冻藏过程中,α-螺旋百分含量由63.28%分别降低到43.70%、41.91%,β-折叠、β-转角、无规则卷曲百分含量逐渐升高,肌原纤维蛋白的总巯基、活性巯基含量逐渐降低,Ca2+-ATPase活性分别下降了63.58%和72.52%。空气、真空两种包装方式对竹荚鱼冻藏期间的肌肉品质影响不大,对蛋白质生化特性有一定影响且真空包装略优于空气包装。由相关性分析可知,两组鱼肉样品的K值、色泽、TBA值、巯基含量、Ca2+-ATPase活性、总蛋白二级结构百分含量与冻藏时间之间、两两之间均显著相关（P<0.05）或极显著相关（P<0.01）,可作为评价竹荚鱼冻藏过程中品质变化的有效指标。研究结果可为深入探究竹荚鱼的品质变化机理和生产实践中的货架期预测提供理论参考。     

不同冷冻方式对调味鱼贮藏品质的影响

为了开发斑点叉尾鮰调理食品并考察不同冷冻方式对其冻藏品质的影响,将加工好的调味鱼进行缓慢冷冻(-18 ℃)、中速冷冻(-30 ℃)和快速冷冻(-80 ℃)处理后,转入-18 ℃贮藏。在贮藏期间,测定调味鱼的pH、挥发性盐基氮(TVB-N)、2-硫代巴比妥酸(TBA)、K值、生物胺,再结合感官评价,分析不同冷冻方式对调味鱼冻藏品质的影响。结果表明,在贮藏期间3种处理的调味鱼pH均随贮藏时间的延长先降低后升高,TVB-N值、TBA值、K值、腐胺、尸胺等随着贮藏时间的延长不断上升。缓慢冷冻的调味鱼在贮藏期间综合品质低于其他2组处理,贮藏末期感官评分已略低于可接受分值,且检出尸胺56.9 mg/kg;中速和快速冷冻的调味鱼直至贮藏末期感官评分均未低于可接受分值,但中速冷冻处理的调味鱼在贮藏末期检出尸胺33.4 mg/kg;快速冷冻的鱼肉在整个贮藏期间未检出尸胺,综合品质较高。     

Safety Assessment of Crayfish (Astacus Leptodactylus ESCH., 1823) from Microbial Load and Biogenic Amines Signature: Impact of Post-Catch Icing and Frozen Storage

In prevalent conditions, fresh-caught fish were held on ice until storage at optimal temperatures. The aim of this study was to investigate and confirm biogenic amines formation and microbiological quality of crayfish during 2 days post-catch icing and 90 days frozen storage. Of the considered biogenic amines in fresh crayfish, puterscine and cadaverine were detected and initial concentrations of them were 5.33 and 50.57 μg/g of flesh, respectively. Psychrotrophs and cadaverine were the major bacteria and biogenic amines detected in crayfish at all sampling stages, respectively. At the end of ice storage, samples had higher biogenic amines and bacterial load when compared with fresh samples (P < 0.05). During the first 30 days of frozen storage, simultaneous with slight changes of biogenic amines, bacterial load significantly decreased (P < 0.05), but as frozen storage time lengthened, progressive development of biogenic amines and microbial load (except for Pseudomonas spp.) was observed. The best correlation was for psychrotrophic with histamine (r = 0.82). At the end of storage, although final values of bacterial load were very negligible, total BAs (487.03 μg/g), especially histamine (110.22 μg/g) exceeded the proposed tolerable maximum levels for total biogenic amines (300 μg/g) and histamine (50 μg/g). It could be concluded that crayfish can be hazardous after 60 days.     

不同前期储藏条件对鲢鱼烹饪特性的影响

研究了不同的前期储藏处理对鲢鱼烹制品质的作用。鲢鱼块在冷藏(-1℃)和冻藏(-20℃)条件下储藏0、3、6、9、12d后进行烹制处理,从化学、物理及感官方面评价储藏温度及时间对烹制后鲢鱼品质的影响。试验结果表明,烹制处理提高了鲢鱼肉的NPN、TVB-N及TMA含量;随储藏时间的延长,冷藏和冻藏的鲢鱼经烹制处理后鱼肉中总氮含量呈逐渐降低趋势,而非蛋白氮(NPN)、挥发性盐基氮(TVB-N)和三甲胺(TMA)含量均呈逐渐增加趋势,冷藏比冻藏的变化趋势显著。储藏时间越长,烹制后鱼肉组织质量劣化越严重。冷藏条件下适宜储藏时间不超过9d,也可延长至12d,且前期冻藏有利于保证鲢鱼肉烹制后的品质。