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。     

Modification of tissue fatty acid composition in Murray cod (Maccullochella peelii peelii, Mitchell) resulting from a shift from vegetable oil diets to a fish oil diet

The dynamics of fatty acid composition modifications were examined in tissues of Murray cod fed diets containing fish oil (FO), canola oil (CO) and linseed oil (LO) for a 25‐week period and subsequently transferred to a FO (finishing/wash‐out) diet for a further 16 weeks. At the commencement of the wash‐out period, following 25 weeks of vegetable oil substitution diets, the fatty acid compositions of Murray cod fillets were reflective of the respective diets. After transfer to the FO diet, differences decreased in quantity and in numerousness, resulting in a revert to the FO fatty acid composition. Changes in percentages of the fatty acids and total accumulation in the fillet could be described by exponential equations and demonstrated that major modifications occurred in the first days of the finishing period. A dilution model was tested to predict fatty acid composition. In spite of a general reliability of the model (Y=0.9234X+0.4260, R²=0.957, P<0.001, where X is the predicted percentage of fatty acid; Y the observed percentage of fatty acid), in some instances the regression comparing observed and predicted values was markedly different from the line of equity, indicating that the rate of change was higher than predicted (i.e. Y=0.4205X+1.191, R²=0.974, P<0.001, where X is the predicted percentage of α‐linolenic acid; Y the observed percentage of α‐linolenic acid). Ultimately, using the coefficient of distance (D), it was shown that the fatty acid composition of fish previously fed the vegetable oil diets returned to the average variability of the fillet fatty acid composition of Murray cod after 70 or 97 days (LO and CO respectively).     

The effects of stress and storage temperature on the colour and texture of pre-rigor filleted farmed cod (Gadus morhua L.)

This experiment deals with the effects of pre‐slaughter stress and storage temperature on muscle pH, fillet contraction, colour and texture in pre‐rigor filleted farmed cod fillets. The fish were either sedated with a low dose of MS‐222 (14.3 mg L^?1) (unstressed groups) or exposed to the air for 3 min (stressed groups) before being submerged in a benzocaine bath (150 g L^?1). The fish were then killed by a blow to the head, their gills cut, filleted and finally stored at either 4 or 20°C. The stressed groups had significantly lower pH values after slaughter (pH=7.0) than the unstressed groups (pH=7.3). This difference was maintained until post rigor for the fish stored at 4°C, but at 20°C it was immediately overshadowed by a decrease in pH caused by temperature‐dependent processes. The length contraction and changes in registered colour values were more pronounced at both the higher temperature and the higher level of pre‐slaughter stress. Again temperature dominated, but significant and consistent effects were registered from stress. No significant effects of stress on texture post rigor were observed. It is concluded that high storage temperature masks the majority of effects caused by pre‐slaughter stress on the measured variables. Stress management protocols, however, are important when the fillets are kept at the common storage temperature of 4°C.     

Effect of Red Beet and Betaine Modulating Oxidation and Bioactivity of Rainbow Trout

The present study compares a control diet to four experimental diets, in which two red beet (14% and 28%) and two betaine levels (0.9% and 1.63%) were incorporated in rainbow trout diets according to a factorial design. The effects of the inclusion of different red beet and betaine concentrations on fatty acid (FA) profile, lipid peroxidation, and antioxidant activity on rainbow trout fillets were investigated. Although no significant differences were observed with the control group, results indicated that red beet and betaine improved fish fillet FA profile, producing an increase in polyunsaturated FAs, mainly docosahexaenoic acid. Higher red beet and betaine concentrations increased flavonoid and phenolic content in the diets; however, no effects were observed for the antioxidant properties of rainbow trout fillets.     

充气比率对罗非鱼片冰温气调贮藏期间品质的影响

采用不同的充气体积（V）与鱼片质量（m）比率包装鲜罗非鱼片，在冰温下贮藏，通过微生物、挥发性盐基氮（TVB—N）和脂质氧化（TBA）等指标考察充气比率对鱼片品质的影响。结果表明，充气比率≥3：1能抑制产品微生物的增长（P〈0．05），贮藏第25天微生物数量仍小于可接受的限（10^6cfu·g^-1）；气调包装样品的肉汁渗出率均高于对照产品，充气比率越大对肉汁渗出率影响越明显；贮藏期间，对照组的TVB—N第4天开始明显高于充气比率≥3：1的样品，第19天时充气比率≥3：1的TVB—N仍在安全限内，约19．30mg·100g^-1；充气比率对产品pH的影响不明显；贮藏期间TBA缓慢上升，气调包装样品之间差异不明显，但与对照组差异显著（P〈0．05）。总而言之，充气比率为3：1～4：1的气调包装样品在贮藏期间品质差异不明显，能明显延长鲜罗非鱼片的货架期。     

Evaluation of cottonseed meal derived from genetically modified cotton as feed ingredients for channel catfish,Ictalurus punctatus

Three laboratory experiments were conducted to assess nutritional quality of cottonseed meals from genetically modified (GM) cotton crops, Roundup Ready^® Flex, Bollgard^® × Roundup Ready, Bollgard II^® × Roundup Ready, and Bollgard II × Roundup Ready Flex for channel catfish, Ictalurus punctatus using Good Laboratory Practices. Growth, feed efficiency, survival, and fillet composition of catfish fed diets containing 20% cottonseed meal from these cotton products were compared with that of catfish fed diets containing cottonseed meals from the near‐isogenic, non‐GM control and non‐GM commercial varieties. Juvenile catfish (mean weights of 4.1, 5.0, and 0.6 g per fish for Experiments 1, 2, and 3, respectively) were stocked in each of 80‐L aquaria and fed experimental diets for 8 weeks. Although there were slight variations in proximate composition, amino acids, and gossypol concentrations, the GM cottonseed meals were not significantly different from the conventional control and the reference cottonseed meals. Weight gain, feed conversion, survival, and fillet composition of catfish fed GM cottonseed meals appeared similar to that of either the control or the commercial cottonseed meals. Results from the present study demonstrate that these GM cottonseed meals are nutritionally equivalent to conventional non‐GM cotton varieties when fed to catfish at 20% of the diet.     

龙头鱼鱼片加工技术研究

研究了以龙头鱼为原料生产龙头鱼鱼片的加工工艺,确定了比较合理的工艺条件。     

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。     

The relationship between flesh quality and numbers of Kudoa thyrsites plasmodia and spores in farmed Atlantic salmon, Salmo salar L

Atlantic salmon, Salmo salar L., were exposed to Kudoa thyrsites (Myxozoa, Myxosporea)-containing sea water for 15 months, and then harvested and assessed for parasite burden and fillet quality. At harvest, parasites were enumerated in muscle samples from a variety of somatic and opercular sites, and mean counts were determined for each fish. After 6 days storage at 4 degrees C, fillet quality was determined by visual assessment and by analysis of muscle firmness using a texture analyzer. Fillet quality could best be predicted by determining mean parasite numbers and spore counts in all eight tissue samples (somatic and opercular) or in four fillet samples, as the counts from opercular samples alone showed greater variability and thus decreased reliability. The variability in both plasmodia and spore numbers between tissue samples taken from an individual fish indicated that the parasites were not uniformly distributed in the somatic musculature. Therefore, to best predict the probable level of fillet degradation caused by K. thyrsites infections, multiple samples must be taken from each fish. If this is performed, a mean plasmodia count of 0.3 mm(-2) or a mean spore count of 4.0 x 10(5) g(-1) of tissue are the levels where the probability of severe myoliquefaction becomes a significant risk.