三聚磷酸钠对鳕鱼片持水性的影响

[目的]分析三聚磷酸钠对鳕鱼片持水性的影响。[方法]通过正交试验研究三聚磷酸钠的溶液浓度、浸泡时间、溶液温度、溶液与鱼片的比例对冷冻鳕鱼片持水性的影响。[结果]4个影响因素对水产品的不同性质的影响效力:对水分含量的影响B>D>C>A;对增重率的影响B>D>A>C;对滴水量的影响A>D>B>C;对煮水量的影响B>D>A>C(A三聚磷酸钠浓度、B浸泡时间、C溶液温度、D溶液∶鱼片比例)。经三聚磷酸钠溶液处理过的鱼片持水性受各因素的交互影响,其中浸泡时间对水分含量、增重率和煮水量的影响最大,溶液浓度对滴水量的影响最大。[结论]采用三聚磷酸钠浓度2.5%,浸泡时间8 min,溶液温度10℃,溶液∶鱼片比例1.0∶0.5的生产工艺进行生产,可获得比较理想的水分含量、增重率、滴水量和煮水量。     

真空冷冻干燥过程参数对罗非鱼片冻干时间及其除水率的影响

通过四因数三水平正交试验,研究了真空冷藏干燥主要过程参数--预冻温度、鱼片(物料)厚度、干燥室压强和加热板温度对罗非鱼Tilapia片冻干时间及其除水率的影响.结果表明:单一过程参数对罗非鱼片单位厚度冻干时间的影响为鱼片厚度越厚,冻干时间越长;预冻温度越高,冻干时间越长;加热板温度越低,冻干时间越长;真空冷冻干燥过程参数对罗非鱼片单位厚度升华冻干时间及其除水率影响的主次因数依次为鱼片厚度>真空室压力>加热板温度>预冻温度.     

冰温下贮藏的青鱼片菌落增长的预测数学模型

将青鱼片分别放在冰温（-0．8℃±0．2℃）、微冻（-2．0℃±1．0℃）和冷藏（4．0℃±1．5℃）的环境下贮藏,对其菌落增长的过程进行动态监测,将不同温度下得到的菌落增长实验值用于建立微生物增殖的初级和二级数学模型。结果表明：Modified Gompertz数学方程能很好地描述低温环境中菌落在青鱼片中的增长情况,并验证了用此数学模型预测菌落增长动态的可靠性,可为冷链控制中的青鱼片货架期预报提供理论依据;而二级数学模型Ratkowsky model在本试验条件下对冰温菌落增长的预测是不适用的。     

不同可食性膜对草鱼鱼片保鲜效果的比较

实验比较了不同可食性抗菌膜对草鱼鱼片的保鲜效果。实验把成膜材料的类型和葱姜蒜混合乙醇提取液添加作为两个因素,制备了6种涂膜液CMC（羧甲基纤维素）、CMCT（羧甲基纤维素＋葱姜蒜提取液）、Chi（壳聚糖）、ChiT（壳聚糖＋葱姜蒜提取液）、NaAlg（海藻酸钠）和NaAlgT（海藻酸钠＋葱姜蒜提取液）。研究发为成膜材料对鱼片的保鲜指标具有显著差异。CMC和CMCT的感官评分均显著低于其它各组,而细菌总数、TVB-N和pH显著高于其它各组;NaAlg和NaAlgT的感官评分与Chi和ChiT组相近,但细菌总数、TVB-N和pH显著低于其它各组。葱姜蒜提取液的添加可显著降低冷藏过程中鱼片的pH值。实验结果表明,海藻酸钠涂膜保鲜鱼片的效果最好。     

抗菌性海藻酸钠涂膜在罗非鱼片保鲜中的应用

采用测定涂膜抑菌性能、缓释效果来探讨抗菌性海藻酸钠涂膜的抑菌机理并将其应用在罗非鱼片的涂膜保鲜中。实验结果表明,抗菌膜是一种具有缓释效果的保鲜膜,对大肠杆菌Esche-richia coli、金黄色葡萄球菌Staphylococcus aureus、枯草芽孢杆菌Bacillus subtilis、腐败希瓦氏菌Shewanella putrefaciens及鱼片表面其他杂菌均有较好的抑制效果,保鲜剂在40h内可从涂膜中完全释放;与未经涂膜处理的对照组相比,抗菌膜可以明显控制鱼片细菌总数的增长、维持较低的挥发性盐基氮值和改善鱼片的感官质量,综合考虑鲜度指标并本着以感官评分为基础的原则,抗菌涂膜处理可以将罗非鱼片的保鲜期延长约5.5d。     

Quality Characteristics of Fresh Rainbow Trout as Perceived by the Danish Processing Industry

The views of Danish processors were sought in an attempt to identify criteria considered important for fresh pan-sized rainbow trout Onchorhynchus mykiss. Principle component regression (PCR) analysis, carried out on the survey data revealed that two components accounted for 55% of the parameter variance. The first component, describing morphometric characteristics, explained 33% of variance and the second, describing skin appearance, explained 22% of the variance. A significant correlation (P < 0.001) was obtained between fillet colour and fillet colour appeal, with preference for white flesh in fish fed unpigmented feed.     

Preslaughter stress and subsequent effect on flesh quality in farmed cod

The aim of this study was to investigate the effect of prehandling stress on the flesh quality of Atlantic cod (Gadus morhua). In order to stress the animal, water was reduced in the tank before a total of 30 fish were caught five at a time using a dipnet and held for 3 min, causing stress by hypoxia. This fish was compared with a control group (n=30) of fish exposed to anaesthetics directly in the tank. All fish were killed by a percussive blow to the head and exsanguinated and stored on ice before flesh quality was measured. Immediately after death and after ice storage for 3 and 8 days, 10 fish per group were measured for muscle pH, texture, fillet gaping, colour, drip loss and cathepsin D. Handling stress resulted in an initial increased fillet lightness, drip loss and decreased fillet shear force, although these differences did level off during ice storage. Stress caused by handling resulted in earlier onset of rigour mortis as compared with the control group, which reached maximum rigour tensions within 26 and 36 h postmortem respectively. We conclude that handling before harvest results in reduced time before entering rigour. After 8 days of ice storage, no effect of handling stress was seen on the muscle pH, flesh colour, fillet shear force, gaping score, drip loss or cathepsin D activity.     

Gaping and loss of fillet firmness in farmed salmon (Salmo salar L.) closely correlated with post‐slaughter cleaning of the abdominal cavity

This study analysed the effect of cleaning intensity of the abdominal cavity and storage temperature from slaughter to the end of processing on the quality of farmed salmon (Salmo salar L.) fillets. These two parameters were manipulated in an experimental setup using in total thirty salmon with an average weight of 4.2 kg. The experiment was designed to imitate realistic scenarios in a normal production process in the Faroe Islands. The salmon stored at low temperatures had an average muscle temperature of 4.65°C, whereas the salmon stored at ambient temperature had an average muscle temperature of 11.27°C. After the salmon were gutted to remove all viscera except the kidney, the abdominal cavity was either rinsed lightly or meticulously cleansed of kidneys, all blood and bodily fluids. A wide range of quality and production parameters were measured either straight after cleaning or after the salmon had been stored in chipped ice at 1.5°C for 7 days. All measured parameters were analysed for possible correlations by principal component analysis (PCA). Blood and remains left in the abdominal cavity were shown to have a significant negative effect on fillet firmness (P < 0.01) and gaping (P < 0.01). The different storage temperatures between slaughter and gutting, tested in this experiment, did not significantly affect fillet firmness or gaping. However, the fillet colour showed significant negative correlation (P < 0.01) with the storage temperatures applied.     

提高冷冻鱼片质量的研究

本文研究了冻前浸渍液处理方法对提高冷冻草鱼片捏的效果。研究结果表明：（１）经浸渍处理的冷冻草鱼片，其液滴损失量减少，蛋白质冷冻变性降低，风味和口感明显得到改善。９２）在五种浸渍液中，以１２％氯化钠与０．２％三聚磷酸钠的混合浸渍液效果尤为显著。     

利用栅栏技术研制H-Aw型即食调味鱼片

确定了H-Aw型即食调味鲅鱼鱼片食品的制作工艺,分析了各种常见栅栏因子对制品感官品质及贮藏稳定性的影响,同时对各种栅栏进行优化,采用多种栅栏因子科学合理的组合,确定其最佳保质栅栏模式。正交试验结果表明:当柠檬酸添加量为0.15%、复合保鲜剂添加量为0.1%(山梨酸钾∶Nisaplin=1∶1)、杀菌前的低温处理时间为36h、采用二次杀菌方式(95℃巴氏杀菌40min,中间在冰水混合物中冷却10min)时,制品在4℃冷藏条件下可保藏8个月以上,并较好地保持其优良品质。