【作者】 张娅楠；

【导师】 邓丹雯；

【作者基本信息】 南昌大学 ， 粮食油脂与植物蛋白工程， 2012， 硕士

【摘要】 本文选用鳗鱼鱼头作为原料,采用复合蛋白酶分步水解法酶解鳗鱼鱼头,以蛋白质水解度为指标,选择Alcalase(碱性蛋白酶)作为第一步水解所用蛋白酶,木瓜蛋白酶作为第二步水解所用蛋白酶,并确定Alcalase水解鳗鱼鱼头最佳水解工艺条件为温度55℃、酶添加量48AU/kg、pH9.0、反应时间200min,木瓜蛋白酶最佳水解工艺为温度65℃、酶添加量250U/kg、pH6.5、反应时间240min。经复合酶分步水解鳗鱼头蛋白质水解度达20.80%。采用低温冷冻干燥技术制备鳗鱼鱼头蛋白Alcalase单一酶水解产物和复合酶水解产物,并用高效液相法分析水解产物氨基酸组成并计算其风味评分值。Alcalase单一酶水解液经冷冻干燥最终产物得率8.35%,Alcalase和木瓜蛋白酶复合水解液经冷冻干燥产物得率为16.01%,复合酶水解物的风味评分值可达201.77,比单一酶水解产物提高了53.91。将单一酶水解产物组和复合酶水解产物添加到新鲜草鱼鱼糜中,冷冻储藏。结果发现储藏80天后,单一酶水解产物组和复合酶水解产物组肌原纤维蛋白含量分别为34.84%和35.41%明显高于空白组和传统抗冻剂组,肌原纤维蛋白ATPase(三磷酸腺苷酶)活力分别维持在21.72%和26.27%,空白组ATPase活力仅为3.32%。采用DPPH自由基、还原力、亚铁离子螯合能力三个体系来评价和比较单一酶水解产物和复合酶水解产物体外抗氧化活性能力。研究发现,单一酶水解产物和复合酶水解产物具有一定的抗氧化效果,其中复合酶水解产物稀释液DPPH自由基清除率最高可达85.17%,单一酶水解产物稀释液也达61.55%。复合酶水解产物还原力、亚铁离子螯合率和DPPH自由基清除率均高于单一酶水解产物。蛋白酶水解法也是提取鱼油的有效方法之一。通过比较隔水蒸煮法、碱水解法、单一蛋白酶水解法及复合蛋白酶水解法鱼油产率确定Alcalase水解200min作为蛋白酶水解提取鱼油最优工艺。对Alcalase水解200min所得鱼油进行理化性质初步分析。蛋白酶水解法所得鱼油酸值0.442、碘值182.63、过氧化值4.54、水分及挥发性物质含量0.1623%、灰分含量0.0330%,符合中华人民共和国水产行业(SC/T3502-2000)一级粗鱼油标准。采用高效液相法分析测定隔水蒸煮法、碱水解法和Alcalase水解法所获得鱼油的脂肪酸组成。蛋白质酶解法所得鱼油中EPA和DHA含量分别为1.84%和8.13%,高于另外两种提取方法。更多还原

【Abstract】 Eel head was chose as raw materials in this report, and was conducted by two-step fractional hydrolysis. Alcalase was selected as the first enzymatic protease, and papain was chose as the second enzymatic protease. The best condition of Alcalase enzymolysis was55℃,48AU/kg, pH9.0, and200min. And the best condition of papain enzymolysis was65℃,250U/kg, pH6.5, and240min. The protein hydrolysis degree of eel head was20.80%.Amino acid compositions in the hydrolysates acquired by single protease and composite proteases were analyzed by HPLC, and the flavor scores were assessed. The yield of hydrolysate by single protease enzymolysis was8.35%, and that by composite proteases was16.01%. The flavor score of the hydrolysate by composite proteases emzymolysis was201.77, which was higher than the other one. The hydrolysates were subjected to low temperature cryodesiccation.These two kinds of hydrolysates were added to grass carp surimi. Grass carp surimi was stored at-25℃.The results found that after80days, the contents of salt soluble protein in the hydrolysate of single protease and the hydrolysate of composite proteases groups were34.84%and35.41%respectively, which were higher than those of the blank group and the traditional antifreeze group. The ATPase activity maintained at21.72%and26.27%, and the blank group ATPase activity was only3.32%.DPPH free radicals, reducing activity and ferrous ion chelating activity were used to evaluate the vitro antioxidant activity ability of these hydrolyastes. The study found that both hydrolyastes had a certain antioxidant effect, and the hydrolyaste of composite protease had a better effect than the other.Protease hydrolysis method was one of the effective ways to extract fish oil. Alcalase hydrolysis in200min was the best one compared with steaming extraction, alkali hydrolysis method and enzymolysis by composite proteases. The fish oil acquired by Alcalase hydrolysis was analyzed by physical and chemical method. The result showed that fish oil’s acid value was0.442, iodine walu was182.63, peroxide value was4.54, the content of water and volatile substance was0.1623%, and ash content was0.0330%. So this fish oil accorded with level1crude fish oil standards(SC/T3502-2000).Fatty acid composition of oil gained by steaming extraction, alkali hydrolysis method and Alcalase enzymolysis was analysed by GC-MS. Fish oil gained by enzymolysis contained1.84%EPA and8.13%DHA, which was higher than the other kinds.更多还原