罗非鱼与四种海水鱼鱼糜比较

比较了罗非鱼与工厂常用的四种海水鱼(黄姑鱼、带鱼、沙丁鱼、鲜丁鱼)鱼糜的基本成分含量、凝胶性能及鱼肌肉蛋白的营养价值。罗非鱼与海水鱼鱼糜的水分含量无显著差异(p>0.05),但蛋白质、脂肪、灰分、盐溶性蛋白含量及pH值有显著差异(p<0.05);罗非鱼鱼糜凝胶的强度、白度显著高于海水鱼(p<0.05),而凝胶的持水性显著低于海水鱼(p<0.05);通过分析几种鱼肌肉蛋白的必须氨基酸含量、氨基酸价(AAS)及氨基酸指数(EAAI),得出罗非鱼肌肉蛋白的营养价值高于黄姑鱼、带鱼和鲜丁鱼,但低于沙丁鱼。     

Postmortem Changes in Mule Duck Muscle Marinated in Red Wine

Postmortem changes in duck breast muscle as affected by red wine marination at 5 °C were studied. Myofibrils were purified from the control (CON) and the red wine marinated muscle (RW) after 0, 1, 3, 7, and 14 d storage. The results showed that myofibril fragmentation index (MFI) was significantly (p < 0.05) higher in RW than in CON samples. Myosin heavy chain, α‐actinin, troponin‐T, titin, and nebulin were degraded more rapidly as seen on SDS‐PAGE in RW than in CON samples. Our results suggested that red wine marination can cause postmortem changes in mule duck breast muscle.     

几种生物大分子对罗非鱼皮Ⅰ型胶原自聚集性的影响

研究海藻酸钠、硫酸软骨素、透明质酸和壳聚糖对罗非鱼皮Ⅰ型胶原自聚集动力学和聚集后微观结构的影响。结果表明:在海藻酸钠、硫酸软骨素、透明质酸和壳聚糖存在的情况下,胶原自聚集过程仍然包含两个阶段:成核阶段和生长阶段,但是各物质对两阶段的动力学参数影响不同。海藻酸钠、透明质酸和壳聚糖均能够降低生长阶段的速率常数,然而对成核阶段的影响各有差异。海藻酸钠对成核阶段的速率常数没有显著影响,但是随着含量的增加能够延长成核时间;壳聚糖能够提高成核阶段的速率常数,同时缩短成核时间;透明质酸对成核阶段的速率常数和成核时间却没有显著影响。而硫酸软骨素对成核阶段和生长阶段均没有显著影响。扫描电子显微镜结果表明海藻酸钠、硫酸软骨素、透明质酸易使胶原纤维横向聚集形成纤维束,影响其直径大小的顺序为硫酸软骨素海藻酸钠透明质酸,而壳聚糖却未表现类似作用。     

Postmortem biochemical behavior of giant squid (Dosidicus gigas) mantle muscle stored in ice and its relation with quality parameters

ABSTRACT:  Several freshness and spoilage indicators were monitored to characterize the postmortem biochemistry of giant squid ( Dosidicus gigas ) mantle muscle. Squid samples were obtained directly from the sea and kept at 0 °C during a 15-d storage period. Data at zero time were obtained from cryogenically frozen samples at time of capture. The adenosine 5'-triphosphate (ATP) degradation followed a different pattern as compared with that from fish species. ATP was almost completely depleted at 24-h postcatch from 6.54 to <1 μmol/g, while at the same time Hx was the predominant catabolite with a concentration of 4 μmol/g, reaching 6.85 μmol/g at day 15. K -value data followed a logarithmic pattern with time instead of a linear one, with no change after day 3, thus reducing its suitability as a freshness index. The coefficient Hx/AMP seems to be an adequate alternative for this purpose due to its constant increment with time. The high NH₄Cl content in mantle muscle (461.3 ± 24.5 mg of NH₄⁺/100 g) derived from its physiological importance for the species compromises the use of the distillation step of the TVB-N analysis commonly used as a spoilage index. This fact explains why the initially high value of TVB-N detected in mantle muscle (243.7 mg N/100 g) did not correlate with the initial low TMA-N content (1.5 ± 0.1 mg/100 g of muscle). The results suggested that under the experimental conditions the shelf life of squid exceeds 15 d.     

罗非鱼的热风干燥特性及其主要成分含量变化研究

研究了罗非鱼鱼片在40、50和60℃等不同热风温度下的干燥速度变化和热风干燥对鱼片的主要成分含量的影响。结果表明,当鱼片厚度一定时,温度越高干燥速度越快,同样厚度的鱼片在较高温度下的干燥时间要比较低温度下的干燥时间至少缩短9h;当温度一定时,鱼片的干燥速度明显受其厚度的影响,鱼片越薄,干燥越快,而且鱼片厚度对干燥速度的影响超过了温度。对于厚度一定的鱼片,在温度恒定时,鱼片中的粗蛋白质含量随着干燥时间的延长而下降。     

宰后不同成熟时间对马肉背最长肌超微结构的影响

以新疆昭苏县公马马肉背最长肌为实验对象,在0～4 ℃下分别成熟1、3、7、14、21、28 d,采用扫描电子显微镜和透射电子显微镜,研究马肉背最长肌在不同成熟时间肌纤维组织学特性的变化。结果表明：肌内膜厚度与肌束膜厚度呈负相关;肌节长度与肌纤维直径和肌纤维面积呈极显著负相关（P＜0.01）,与肌纤维密度呈正相关。肌纤维直径与肌纤维密度呈负相关,与肌纤维面积呈极显著正相关（P＜0.01）。随着成熟时间的延长,肌原纤维超微结构发生变化,肌原纤维排列由整齐到疏松,由清晰到杂乱;成熟14 d时Z线开始降解。     

Postmortem Changes of Cultivated Atlantic Salmon and Their Effects on Salt Uptake

Rigor mortis of cultivated Atlantic salmon (Salmo salar) began to set in 8h after death and was fully resolved 60–70h after death during storage at 0°C. Maximum muscle contraction was observed 24–30h after death. ATP content decreased from 7.25 to 0.14 to 0.09 μmol/g fish from pre-rigor mortis to in-rigor mortis to post-rigor mortis state. The inosine and hypoxanthine contents increased from 0 to 1.20 to 4.06 μmol/ g fish and from 0.08 to 0.33 to 0.84 μmol/g fish during 60h storage, respectively, during 60h of storage at 0°C. Postmortem changes affected salt uptake. The equilibrium salt concentrations of pre-rigor, in-rigor and post-rigor mortis salmon were 0.53, 0.66 and 0.75 g/g salt-free solids, respectively, in a 20% (w/v) sodium chloride solution at 10°C.     

大足黑山羊宰后成熟过程中感官与理化性质的变化

本实验以大足黑山羊后腿肉股四头肌为实验材料,测定其在成熟过程中的感官及理化指标（滴水损失、色泽、剪切值、蒸煮损失、pH值、糖原含量、肌原纤维小片化指数（myofibrillar fragmentation index,MFI）、挥发性盐基氮（total volatile basic nitrogen,TVB-N）含量和硫代巴比妥酸（thiobarbituric acid reactive substances,TBARS）值）的变化。结果表明：滴水损失、pH值、糖原含量、TBARS值等发生明显变化,并且主要变化在宰后前72 h内基本完成,而滴水损失、pH值在24 h后变化不显著（P＞0.05）;MFI值在成熟24 h后变化差异显著（P＜0.05）;TVB-N含量在0～72 h时,符合一级鲜肉的标准。羊肉的成熟时间依感官、色泽、pH值、TBARS值等指标的变化判断,以72 h为宜;从TVB-N含量的变化看,成熟时间应小于72 h。综合考虑,确定大足黑山羊的最佳成熟时间为72 h。     

罗非鱼肉的酶法水解控制和复合研究

利用Flavourzyme、Protamex、Alcalase2 4L、Trypsin、Kojizyme、木瓜蛋白酶、中性蛋白酶和虾头蛋白酶对罗非鱼肉进行水解 ,以游离氨基酸态氮含量、TCA可溶性蛋白 (短肽 )含量和水解度为指标对酶解过程进行分析 ,研究了酶法水解的控制条件以及不同酶水解生成产物的特点 ,在此基础上选择控制酶解的方法以得到较高的TCA可溶性蛋白 (短肽 )含量 ,并进行了复合酶解的比较研究。     

Recovery and Properties of Muscle Proteins Extracted from Tilapia (Oreochromis niloticus) Light Muscle by pH Shift Processing

ABSTRACT: Functional proteins can be extracted from fish muscle using acid- or alkali-aided solubilization and recovered with isoelectric precipitation. It was of interest to evaluate acid- and alkali-aided solubilization/precipitation on muscle material from the warm-water fish tilapia. Higher levels of proteins were extracted with high compared with low pH ( P < 0.05) because of higher protein solubility at high pH. Protein extraction was not influenced by the specific low or high pH tested or homogenization time. Similar protein types were extracted for the low and high pH solubilization, while proteolysis was observed at low pH. Viscosity was significantly higher at pH 2.3 to 2.9 compared with pH 10.8 to 11.4 ( P < 0.05) and varied greatly at low pH indicating a more unstable system. Two different low (pH 2.5 and 2.9) and high (pH 11 and 11.2) solubilization pH values were selected and protein recovery investigated in the pH range 5.1 to 5.7. The alkali-extracted proteins had more solubility at pH 5.1 to 5.7 ( P < 0.05) and thus less protein ( P < 0.05) was precipitated compared with the acid-aided process. More protein was recovered as pH increased from 5.1 to 5.7 ( P < 0.05). More protein types were found in the supernatant after precipitation for the alkali-aided treatment, and soluble proteins were similar to those of untreated tilapia muscle homogenate. Viscosities of the acid- and alkali-extracted proteins at pH 5.1 to 5.7 were significantly higher than the viscosity of native proteins at that pH ( P < 0.05). While this study demonstrated significant differences in protein extractability and precipitation of the 2 processes, no statistical difference ( P > 0.05) was found for overall protein recovery (61% to 68% for alkali-aided process and 56% to 61% for acid-aided process) of the 2 processes.     

冻融循环过程中冷冻罗非鱼片呈味物质的变化

为探究冷冻水产品冷链流通过程中的品质变化,以罗非鱼为研究对象进行7次冻融循环.分析8组样品基本营养成分差异,通过电子舌确定其整体滋味轮廓差异,并分析游离氨基酸、呈味核苷酸、呈味无机离子的含量,并结合人工感官评分分析呈味物质的变化.结果 显示,罗非鱼片冻融循环过程中整体滋味轮廓可有效区分,随着冻融次数的增加,鲜甜味氨基酸...     

不同漂洗处理对罗非鱼浆的影响

分析了水洗、酸洗和盐洗对罗非鱼浆的脱水性、罗非鱼糜凝胶的持水性、白度及凝胶强度的影响,并对漂洗中干物质的损失率作了分析.结果表明:酸洗和盐洗可以使鱼浆易于脱水,各种漂洗都可以提高鱼糜凝胶的持水性、白度及凝胶强度,但提高程度随漂洗处理的不同而异.酸洗可以降低鱼浆中干物质的损失.     

Technological Studies on the Dehydration of the Nile Bolti Fish (Tilapia nilotica)

Chemical and microbiological analysis of bolti fish: moisture, chloride, fat, total volatile bases (T.V.B.), thiobarbituric acid value (T.B.A.), total bacterial count and coliforms were estimated in fresh bolti fish, after brining, drying and during storage at room temperature for 3 months. The moisture content decreased after drying but become stable during the storage period. Chloride increased after brining but no noticeable changes were observed after drying and during 3 months storage. The fat content was not affected by previously processes. T.V.B. and T.B.A. increased after brining, drying and throughout storage period. The rate of increase was higher for dehydrated samples than for sun-dried ones. The reduction of total bacterial count is due to the high salt content and the lack of free water in fish tissues after drying. Coliforms were not present after brining, drying and throughout the storage periods.     

罗非鱼片渗透处理中的水分传递特性

为了研究水产食品原料在不同的渗透处理条件下的水分传递规律,本实验选择了罗非鱼片为研究对象,采用食盐溶液作为渗透液,在改变渗透液浓度、固液比和鱼片厚度的条件下,研究了罗非鱼片的水分迁移变化特性.结果表明,鱼片在10%浓度的盐水溶液中表现为吸水增重,在20%以上的盐水中才会出现渗透脱水现象;在渗透液浓度和鱼片厚度不变的条件下,鱼片的脱水率随着固液比的增大而升高;同时厚度对鱼片脱水率的影响与渗透时间有关,渗透时间的延长会降低较薄鱼片的脱水率.     

超高效液相色谱-串联质谱联用测定罗非鱼肌肉中甲基睾丸酮残留

建立罗非鱼肌肉中甲基睾丸酮残留量的超高效液相色谱-串联质谱联用(ultro high performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)测定方法。以氘代试剂为内标,样品经乙腈萃取后,乙酸乙酯液液分配,强阴离子交换柱净化,正己烷液液分离,硅酸镁固相萃取柱净化,采用UPLC-MS/MS选择离子监测(selected ion monitoring,SIR)正离子模式测定,可对罗非鱼肌肉中甲基睾丸酮残留进行定性和定量检测,检出限为0.4μg/kg,定量限为1μg/kg。线性范围为1～60μg/kg(r＞0.999),方法的平均回收率范围为71.06%～83.06%,相对标准偏差为7.4%～15.3%。完全满足食品安全及进出口罗非鱼肌肉中甲基睾丸酮残留的监控和检测需要。     

Influence of Postmortem Changes in Bovine Muscle on the Water-Holding Capacity of Beef. Postmortem Storage of Muscle at 20°C

Rigor mortis occurs in bovine neck muscles as soon as pH 5.9 and an ATP level of about 1 μMol/g are reached. At 20°C muscle contraction does not occur before the onset of rigor. Postmortem changes in water-holding capacity (WHC) were followed by measuring the cooking loss of unsalted and salted (2% NaCl) muscle homogenates prepared after storage of the intact muscle tissue at 20°C for different periods postmortem. At tissue pH above 5.9 addition of salt causes a strong increase of WHC of muscle homogenates. There is a small decrease of WHC of both unsalted and salted homogenates during the prerigor phase which is apparently caused by the postmortem fall of pH. Rigor mortis does not influence the WHC of unsalted muscle homogenates but causes a strong decrease of WHC of salted homogenates. The reason for this difference is discussed. No more than one-third of the total postmortem decrease of WHC and protein solubility in salted muscle homogenates was attributed to the fall of pH, so at least two-thirds were due to the development of rigor.     

Effect of Slaughter Method on Postmortem Changes of Grass Carp (Ctenopharyngodon idella) Stored in Icesti

ABSTRACT: The effect of 2 slaughter methods (immersion in ice-water slurry and electrical stunning followed by ice slurry asphyxiation) on the quality of grass carp ( Ctenopharyngodon idella ) stored in ice for 20 d was evaluated using sensory and chemical analysis. Electricity immediately stunned the fish and did not induce blood spots in the flesh. Fish killed by electricity showed a faster initial rate of ATP degradation and entered into rigor mortis earlier, but did not show significant differences in the sensory score when compared with fish killed by immersion in ice-water slurry. Thus, no differences were observed in the shelf life of carps between the 2 slaughter methods evaluated. The limit for acceptability of grass carp stored in ice was around 13 to 16 d. Grass carp accumulated more inosine than hypoxanthine. K, Ki, P , Fr, and H values were highly correlated with storage time and with the TFRU sensory scores in both groups; these could be used to assess the freshness quality of grass carp.     

基于质构变化的罗非鱼片冻藏保质期预测

探究预测罗非鱼保质期的新方法,测定真空包装罗非鱼片的质构参数、pH值、电导率、水分活度和挥发性盐基氮含量在－5、－20 ℃和－40 ℃贮藏条件下随时间延长的变化趋势;求取各质构参数变化和品质参数变化的Pearson相关性,并以其为依据,选取内聚性和弹性作为指示真空包装冻罗非鱼片品质变化及保质期终点的指标;得出当内聚性0.20、弹性0.65时为鱼片保质期的终点;分别建立内聚性和弹性变化与贮藏时间的一级动力学方程,求取其变化速率常数与贮藏温度间的Arrhenius方程。实验求得基于内聚性一级动力学方程的反应活化能Ea=53.532 kJ/mol,指前因子k0=215.64;基于弹性活化能Ea=89.866 kJ/mol,指前因子k0=1 620.68,根据上述研究参数分别预测冻罗非鱼片保质期,其结果与实测值的误差均在可接受范围内。结果证实：冻罗非鱼片内聚性和弹性均可以作为预测冻罗非鱼片保质期的参数依据。     

牡蛎壳源丙酸钙对罗非鱼肉防腐保鲜作用研究

研究了牡蛎壳源丙酸钙对罗非鱼肉的防腐保鲜作用。通过测定菌落总数、pH、TVB-N值、TBA和感官评价,对比分析了蒸馏水处理和不同浓度丙酸钙浸泡处理后罗非鱼肉在4℃贮藏期间的品质变化。结果表明,牡蛎壳源丙酸钙对罗非鱼肉具有防腐保鲜效果,并随着丙酸钙的浓度增加而增强,以5%效果较好。通过对牡蛎壳源丙酸钙抑菌作用的研究,可以减少牡蛎壳资源的浪费,提高鱼肉的贮藏期限。