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。     

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。     

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.     

Effect of the Inclusion of Dried Tetraselmis suecica on Growth,Feed Utilization,and Fillet Composition of European Sea Bass Juveniles Fed Organic Diets

Dried Tetraselmis suecica was evaluated as a fish protein substitute when incorporated to replace (protein basis) 10% (TETRA10) and 20% (TETRA20) of the control diet. The diets were offered to nine groups of European sea bass (72 g) over 63 days. Test diets did not affect zootechnical performances nor carcass or fillet yields and proximate analysis of edible portion. Feeding TETRA20 resulted in lower apparent digestibility coefficients of protein, lipid, and organic matter, and hepatosomatic index compared to the control diet. T. suecica was able to replace up to 20% of fish protein without hampering growth performance and major quality traits of sea bass.     

Significant Augmentation of Sunshine Bass Morone chrysops x M. saxatilis Fillet Highly Unsaturated Fatty Acid Content without Impact on Oxidative Stability or Sensory Attributes

We evaluated production performance, fillet composition, and sensory integrity of sunshine bass (Morone chrysops x M. saxatilis) fed a marine oil-based finishing feed after being raised on a plant oil-based production feed. Two feeds containing either corn oil (CO) or menhaden oil (MO) were fed to sunshine bass according to different feeding regimens at the close of the production cycle: control groups were fed the CO or the MO feeds exclusively; remaining groups were transitioned from the CO feed to the MO feed at 4-, 8- or 12-week intervals. Replacing MO with CO yielded fillets with distinctly different fatty acid profiles; however, finishing with an MO-based feed for 4–8 weeks offered significant compensation for reductions in fillet nutritional quality. Production performance and fillet sensory characteristics were largely unaffected by dietary lipid source, suggesting fillet fatty acid profile can be manipulated to maximize nutritional value of cultured fillets without reducing consumer acceptance.     

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。     

The effects of partial replacement of fishmeal protein by hydrolysed feather meal protein in the diet with high inclusion of plant protein on growth performance,fillet quality and physiological parameters of Pengze crucian carp (Carassius auratus var. Pengze)

Goal of this research is to explore the effects of graded dietary levels of hydrolysed feather meal (HFM) protein as an alternative of fishmeal protein on Pengze crucian carp (Carassius auratus var. Pengze). Five isonitrogenous (35% crude protein) diets were formulated as Control diet and four other diets F15, F30, F45 and F60 wherein 15%, 30%, 45% and 60% fishmeal protein replaced by HFM protein fed for 70 days. The results showed that fish growth was unaffected up to 45% fishmeal protein replacement. Dietary HFM protein could reduce the crude protein composition of body and further affect fillet quality through a significant increase in springiness, gumminess, chewiness and/or resilience. Activity of digestive enzymes (amylase, lipase and tryptase) increased as the fishmeal protein replacement increased, whereas a higher replacement level had negative impacts on absorptive capacity of intestine by decreasing its absorptive area, following by a reduction in concentration of lactate dehydrogenase, total cholesterol, high‐density lipoprotein, low‐density lipoprotein and ammonia in serum. Although intestinal antioxidant parameters were elevated by dietary HFM protein , the content of malondialdehyde in intestine was also positively associated with the protein replacement level. Overall, our results indicate that up to 45% of fishmeal protein could be replaced by HFM protein in diet without significant impact on the growth of Pengze crucian carp, whereas the crude protein content of whole body, fillet quality and oxidative status would significantly be affected when the replacement level of fishmeal protein reaches 30% together with a negative effect on the intestinal histology.     

Protein‐to‐energy ratio of 21.43 g MJ−1 improves growth performance of Nile tilapia at the final rearing stage under commercially intensive rearing conditions

This study evaluated the effect of ratio of dietary digestible protein (DP) to digestible energy (DE) on growth performance, fillet chemical composition and haematological profile of Nile tilapia subjected to transport‐induced stress at the final rearing stage (450 to 800 g) under commercial conditions. The trial was conducted using a 5 × 2 factorial layout (DP: 200, 230, 260, 290 and 320 g kg^?1) and (DE: 12.6 and 13.8 MJ kg^?1). Energy levels did not influence any analysed parameters in this research. Final weight and biomass gain were increased up to the ratio of 269 and 270 g PD kg^?1, respectively, and feed conversion ratio was reduced down to a 275 g DP kg^?1. Protein efficiency ratio linearly decreased from 200 g DP kg^?1 diet to 320 g DP kg^?1. There was no statistical difference in fillet chemical composition. Red blood cell count (RBC), haemoglobin (Hb), mean corpuscular volume (MCV) and mean corpuscular haemoglobin concentration (MCHC) were different before and after transport‐induced stress. Leucocyte differentiation after transport‐induced stress revealed lymphocytopenia and neutrophilia. We conclude that for tilapia weighing 450–800 g reared under commercially intensive conditions, a diet with 270 g DP kg^?1 and 12.6 MJ DE kg^?1 (21.43 g DP MJ^?1 DE) can improve the growth performance and ensure the fish health.     

Effects of Tea Polyphenol Combined with Nisin on the Quality of Weever (Lateolabrax japonicus) in the Initial Stage of Fresh-Frozen or Chilled Storage State

This study investigated the effects of tea polyphenols (TPs) combined with nisin (N) on the quality of weever fillet in the initial stage of fresh-frozen (FF) state or chilled storage (CS) state for 7 days. The physicochemical (pH, K value, total volatile basic nitrogen, thiobarbituric acid [TBA], total bacterial colony count, total mercaptan content, and free amino acid) and sensory properties of weever fillet were periodically analyzed. Compared with single treatments, TP + N treatment effectively improved the physicochemical and sensory attributes of weever fillet and reduced its microbial growth. As such, the quality of the weever fillet was significantly maintained. Therefore, the use of TP + N as a complex preservative may be a promising method to maintain the quality of weever fillet and to extend its shelf life at FF or CS state.     

Influence of temperature on growth,feed consumption and chemical composition in the muscle of Pacu Piaractus mesopotamicus

The zootechnical performance of fish can be influenced by temperature through the induction of metabolic changes that are likely to affect growth and body composition. Thus, the objectives of this study were: (a) to examine the influence of five different temperatures (18, 21, 24, 27 and 30°C) on growth performance and metabolic parameters and (b) to evaluate the relationship of the protein efficiency ratio (PER) with the fillet proximate composition of Pacu juveniles. Growth and feed consumption (FC) were positively correlated with temperature (R² = .95), while PER and FC were negatively correlated with temperature (R² = .89). For the fillet composition, ethereal extract increased, and moisture decreased with the temperature. Protein content was lowest at 18 and 30°C and highest at 21, 24 and 27°C. The robust adjusted curve between PER and fillet protein content in relation to temperature showed the best result at 21°C. The obtained results indicate that Pacu juveniles reared between 21 and 27°C showed better protein efficiency with regard to FC, and this effect reflected better meat quality.