响应面法优化罗非鱼鱼皮胶原多肽螯合镁的工艺条件的研究

以罗非鱼鱼皮为原料,研究鱼皮胶原多肽和镁离子的螯合工艺条件.探讨了鱼皮胶原多肽与氯化镁的质量比、反应体系的pH、螯合温度、螯合时间等因素对鱼皮胶原蛋白螯合反应的影响;在单因素实验的基础上,通过响应面法对鱼皮胶原多肽与镁的螯合工艺条件进行优化,确定最佳的螯合工艺条件为:质量比1∶5、pH7.0、螯合温度70℃、螯合时间30min.在此条件下,螯合率达84.58％.通过对比螯合反应前后傅里叶变换红外光谱图的变化,证明了鱼皮胶原多肽与镁离子形成了新的螯合物.     

喹乙醇在罗非鱼肌肉组织的残留初探

应用空白罗非鱼 ,做鱼体喹乙醇残留试验。试验分为三组。一组为不食用添加喹乙醇饲料的鱼 ,另外两组为食用添加不同量喹乙醇的饲料的鱼 ,添加量分别为 5 0 0mg/kg、2 5 0 0mg/kg。喂养 15天后 ,应用液相色谱分析方法测定鱼肌肉组织的残留。第一组未检出喹乙醇。第二组和第三组在体内均有残留。并且与饲料的含量呈正比。连续测定 5天后改喂第一组鱼食用的饲料 ,在 2 4h内喹乙醇残留减少 ,在 4 8h就未测出喹乙醇的量     

Tocopherol in the lipid stability of tilapia (Oreochromis niloticus) hamburgers

Presence of tocopherol is effective for fish preservation during frozen storage, inhibiting lipid degradation by oxidation. This work evaluated the antioxidant effects of α-tocopherol in diet and postmortem addition on the final quality of hamburgers produced from tilapia fillets kept frozen for zero, 30, 60, and 90 days. Chemical composition varied within the values found for tilapia fish. The increase in α-tocopherol levels reduced the values of thiobarbituric acid reactive substances (TBARS) in the samples at all time intervals. Tocopherol supplementation in diets protected the hamburgers from lipid oxidation more effectively than postmortem addition.     

鲜姜汁对罗非鱼蛋白质水解作用的研究

利用鲜姜汁水解罗非鱼肉蛋白质。以水解度及水解液中可溶性蛋白、可溶性固形物为指标,分析了水解温度、时间、pH、料液比以及加姜汁量对水解效果的影响,并采用L16(45)正交实验优化水解条件。确定水解条件为:料液比1∶3(m/v,g/mL),姜汁加量为0.3mL/g(E/S),水解温度45℃,时间2.0h、pH8.0。实验结果:水解液中氨基态氮含量为1.412g/L,水解度为22.49%,可溶性蛋白19.28g/L,可溶性固形物5.75%。水解液无腥味,呈淡黄色。     

响应面法优化罗非鱼肉内源酶酶解工艺

为促进罗非鱼加工下脚料的利用,用响应面方法研究了pH,值、时间、温度三条件对内源酶酶解罗非鱼肉蛋白的影响,建立了拟合良好的回归方程。最优水解条件为温度58．0℃,pH7．49,时间5．83h,水解度最大值为7．4689％。     

利用罗非鱼下脚料制备生物柴油的SWOT分析

运用SWOT模型分析法,对利用罗非鱼下脚料制备生物柴油的优势、劣势、机会和威胁四个方面分析,分析表明优势集中体现在政策、资源和特色等方面,劣势体现在技术、资源弱化和商品流通等方面,同时表明发展机会现实上存在但具有一定的威胁。     

Gelation of protein isolates extracted from tilapia light muscle by pH shift processing

The gelation properties of protein isolates extracted from tilapia muscle with acid and alkali-aided processing were compared to washed tilapia muscle. Gels were prepared with and without the addition of 2% NaCl (w/w) slightly above neutral pH and gelation properties and gel quality were determined using various procedures. Hardness and elasticity of gels as assessed by torsion testing was improved using 2% NaCl (w/w) compared to treatments without salt. Small strain oscillatory testing showed that storage modulus (G′) of gel pastes prior to thermal gelation was significantly higher in the absence of salt, while smaller differences were seen after thermal gelation. Small strain oscillatory tests demonstrated a different gel forming mechanism for acid and alkali treated proteins compared to washed muscle. Fold tests demonstrated that acid treated proteins and washed muscle had significantly lower gel quality compared to alkali treated proteins. Addition of salt in gels improved gel water-holding capacity for acid and alkali treated proteins. Overall, the acid treated proteins exhibited poorer gelling ability compared to alkali treated proteins. Total content of SH-groups was measured before and after gelation and S–S bonding did not explain the difference in gel forming ability of different treatments. The results indicate that the alkali-aided process can be used to produce high quality protein gels from tilapia muscle suitable for manufacturing of imitation seafood products.     

利用罗非鱼头提取硫酸软骨素的工艺探讨

以罗非鱼头为原料,初步探讨了硫酸软骨素的提取工艺,采用稀碱提取,酶解,三氯乙酸沉淀蛋白,乙醇沉淀的方法,考察了碱提取过程中碱浓度、料液比、温度、时间对提取率的影响,在单因素实验的基础上,利用正交实验进行了优化。得出了在碱浓度1%、料液比1∶5、提取温度50℃、提取时间7h,最大的得率为3.757%。     

Effect of gamma irradiation on the keeping quality and nutrients of tilapia (Oreochromis mossambicus) and silver carp (Hypophthalmichthys molitrix) stored at 1.C

Fillets (skin on) obtained from freshly killed tilapia (Oreochromis mossambicus Peters) and silver carp (Hypophthalmichythys molitrix Curier & Valenciennes) were gamma irradiated at 1.0 kGy at 2–4.C. The chemical con position and thiamin and riboflavin contents of irradiated fish fillets were analysed and compared with those of the non-irradiated fish. Loss of thiamin content of silver carp fillets was significant whereas the thiamin content of tilapia and other constituents of tilapia and silver carp were unaffected. Irradiation at 1.0 kGy markedly reduced the bacterial level of tilapia and silver carp. No significant increase in total counts in both irradiated and non-irradiated samples was found during 5 days' storage at 1.C. The pattern of nucleotide changes in tilapia and silver carp was different. Irradiation had little effect on the concentrations of nucleotide catabolites in both species. Sensory evaluation of flesh colour and flavour was conducted after 5 days' refrigerated storage. Except that the colour of irradiated carp was more reddish, there were no significant differences in other qualities.