生食金枪鱼肉冷藏过程鲜度的变化

对解冻生食黄鳍金枪鱼肉0、2、4、6、8℃冷藏过程中鲜度变化展开系统研究,以K值小于20%确定各冷藏温度下生食终点,冷藏过程中采用K值、p H等指标评价品质,获得生食金枪鱼肉冷藏品质变化规律。生食黄鳍金枪鱼肉冷藏过程ATP关联物中ATP快速下降,ADP、AMP缓慢下降,IMP有累积趋势,Hx R蓄积量较大,为Hx R生成型鱼种。p H在生食期间没有显著差异,对鲜度高的生食生鱼片品质不适合采用p H判断鲜度间的小差异。建立生食金枪鱼肉冷藏K值随时间变化规律的动力学模型,模型符合一级动力学反应方程。冷藏温度对反应速率常数的影响用Arrhenius方程描述,有较高的拟合精度。      

基于NAD的分解对金枪鱼块流水解冻工艺的优化

为对高品质金枪鱼流水解冻工艺进行优化,本实验将鱼肉从-60℃超低温冰箱中取出后在-12⁰℃的低温冰箱中贮藏相应的时间后再流水解冻。结果表明:-6℃15 h和-9℃3 d冷藏贮藏后流水解冻可有效缓解鱼肉收缩现象,减少汁液流失,比直接流水解冻具有更好的咀嚼特性,与冷藏室解冻相比无显著性差异。对优化解冻过程中金枪鱼三磷酸腺苷（ATP）、烟酰胺腺嘌呤二核苷酸（NAD）含量变化进行检测分析,结果表明当NAD分解至0.20μmol/g,ATP降解到2.0μmol/g时,既能缓解鱼肉收缩、降低汁液流失,又能保证K值在一级鲜度20%范围内。本研究采用的优化工艺可有效提高冻结金枪鱼流水解冻的品质。      

基于MSTSO算法的冷水机组负荷分配模型研究

为降低空调系统的运行能耗,优化冷水机组的负荷分配,首先提出了一种多策略改进的金枪鱼优化算法(MSTSO),引入黄金正弦觅食机制和非线性惯性权重来加强算法对最优解的全局定位能力;通过蜜獾随机搜索策略赋予算法更强的性能以跳出局部最优。接着利用双向长短期记忆网络(BiLSTM)搭建能效预测模型并用MSTSO算法对其初始参数进行寻优从而获得最佳训练效果。最后进一步提出BiLSTM-MSTSO负荷分配模型,对多台冷水机组的负荷进行合理分配与优化。实验结果表明,优化后的BiLSTM预测模型拥有更高的预测精度,MSTSO算法相较其他智能优化算法可以减少更多的能耗并最大化提升冷水机组的运行效率。因此BiLSTM-MSTSO智能模型适用于多冷水机组的能耗预测与优化。     

金枪鱼鱼松的工艺研究

研究金枪鱼的营养成分、鱼肉脱腥方法,并研究了全营养金枪鱼鱼松加工工艺。因金枪鱼肉中脂肪含量高,使鱼肉制品存在鱼腥味,采用萃取法脱去鱼肉中的脂肪,去脂率高达95%。试验结果表明,金枪鱼富含蛋白质、DHA、EPA和矿物质;各因素对调味配方影响的主次顺序为:D>A>C>B,即最适宜的调味配方为盐1.5%、糖3.0%、大豆分离蛋白5.0%、姜汁3.0%、葱汁1%、味精1%、油3%;各因素对鱼松工艺影响的主次顺序为A>D>C>B,即最佳处理工艺为压榨水分55%,蒸煮时间75 min,初炒时间10 min。     

Power and temperature distribution during microwave thawing, simulated by using Maxwell's equations and Lambert's law

The microwave thawing of frozen food was simulated by using an equation to describe heat conduction. This was based on the fact that the thermal and dielectric properties of food vary with temperature. The microwave power absorbed was modelled by using Maxwell's equations and Lambert's law. The power and temperature distributions calculated using both models were compared. Although Lambert's law is theoretically less applicable for simulating the transmitted microwave power, it provided an effective numerical approach for calculating temperature distribution during microwave thawing, which proved compatible with experimental results.     

Synthesis of docosahexaenoic acid-rich triglyceride with immobilizedChromobacterium viscosum lipase

Docosahexaenoic acid (DHA) in the free fatty acid (FFA) derived from enzymically hydrolyzed tuna oil was concentrated by partial titration and precipitation of other FFA as sodium salts with acetone. A triglyceride containing up to 46.2% DHA was synthesized from the DHA-rich glyceride mixture and FFA by use of an immobilizedChromobacterium viscosum lipase.     

3种金枪鱼头不同部位成分比较及营养学评价

分析黄鳍金枪鱼、大眼金枪鱼和马苏金枪鱼鱼头不同部位（鱼肉、鱼皮和鱼骨）的基本营养成分,并评价其营养价值。结果表明：3 种金枪鱼鱼头均含有丰富的粗蛋白、粗脂肪和灰分;3 种金枪鱼鱼头的鱼肉中必需氨基酸种类齐全,必需氨基酸与总氨基酸含量的比值接近40%,氨基酸评分较高,必需氨基酸指数大于86,属于优质蛋白;而鱼皮和鱼骨中蛋白质的营养价值相对较低;3 种金枪鱼鱼头的脂质中饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸的比例接近于1∶1∶1,富含二十二碳六烯酸（docosahexaenoic acid,DHA）和二十碳五烯酸（eicosapentaenoic acid,EPA）,其含量分别为15.69%～23.29%和4.02%～5.15%,DHA与EPA的比值为3.23～5.27,n-6与n-3多不饱和脂肪酸的比值为0.13～0.29,具有较高的营养价值;3 种金枪鱼鱼头中还富含对人体健康有益的Ca、Fe、Zn等矿物质元素。     

Tuna Protein Nutritional Quality Changes after Canning

Albacore tuna (Thunnus alalunga) was steamed and canned in soy bean oil and sterilized at 115°C for 55 or 90 min. Proximate composition, total amino acid and available lysine content were determined during different phases of the process. Water and protein were lost in all phases and fat content increased. There was a decrease in available lysine during cooking but no loss in total amino acids. Nutritional evaluation of the protein showed differences in biological value and net protein utilization when the canned tuna was mixed with bread flour.     

Effect of gas packaging conditions on thawed Thunnus obesus preservation

Shelf-life of commercial thawed tuna was studied in different packaging atmospheres: Air, High O₂ (70%O₂/30%CO₂), Sprayed green tea extract in High O₂, Low O₂ (40%O₂/40%CO₂/20%N₂), Non O₂ (60%CO₂/40%N₂) and Carbon monoxide (60%CO₂/39.5%N₂/0.5%CO). Three-cm-wide slices were analysed at days 0 (24 h post-thawing), 4 and 6 from the date of packaging while kept in retail conditions. Analysis performed each day of the study were: gas concentration in the headspace, colour, pH, exudative losses, lipid oxidation, total volatile bases nitrogen, microbiological analysis and a sensory test (fresh and cooked fish). The atmospheres ‘Non O₂’ and ‘Low O₂’ were the most effective for increasing tuna shelf-life due to better general lipid oxidation characteristics, microbial counts and sensory results. Shelf-life reached up to 6 days post-thawing in these cases although tuna should be consumed cooked to prevent risk of pathogens or toxins. Also, the use of antioxidants or carbon monoxide improved colour and flavour attributes and should be considered as alternatives for packaging.