【作者】 林流丹；

【导师】 欧仕益；

【作者基本信息】 暨南大学 ， 食品科学， 2008， 硕士

【摘要】 随着我国罗非鱼产量的逐年增加,开展罗非鱼的增值加工显得日益迫切。本研究以罗非鱼肉的酶解物为原料,探讨利用树脂分离其酶解液中低聚肽的可行性,从而提高罗非鱼的附加值,并降低低聚肽的生产成本,以便于其产业化,满足人们对保健低聚肽产品的需求。主要结果如下:(1)罗非鱼酶解工艺:底物浓度(煮熟鱼糜)5%,Alcalase酶添加量为2300μ/g.鱼蛋白,在pH=8.0,55℃下反应4h后,灭酶,离心(过滤),得上清液。在此条件下,可获得平均水解度为17.86%的酶解液。(2)酶解液中游离氨基酸的脱除:采用阳离子交换树脂732分离酶解液中的游离氨基酸及低聚肽,具体工艺为:料液pH为3.0,室温下以流速1mL/min上柱;用1mol/L NaOH溶液洗脱,洗脱速度为1mL/min。残余蛋白(多肽)、氨基酸含量、平均水解度及离子色谱结果表明,阳离子交换树脂能有效吸附氨基酸,吸附率为82.16%,但对残余蛋白(多肽)吸附少,吸附率仅为36.30%,且平均水解度无显著变化;1mol/L NaOH溶液除能洗脱游离氨基酸外,还能洗脱碱性氨基酸比例大的小分子低聚肽,洗脱率为78.07%。(3)低聚肽的分离:静态交换实验表明,大孔树脂AB-8能有效吸附低聚肽。通过紫外特征吸收、氨基氮含量、平均水解度、平均肽链长度变化、F值及离子色谱,确定其最佳柱层析工艺为:料液直接上柱,流速1mL/min;采用5%乙醇溶液洗脱,洗脱流速为1mL/min;在此条件下,可获得平均肽链长度分别为1.18～6.43的低聚肽。产物的紫外吸收图谱、离子色谱图和氨基酸自动分析结果表明,产物氨基酸种类较多,表明获得的低聚肽为多种低聚肽的混合物,需进一步分离纯化。更多还原

【Abstract】 China is the largest country for Tilapia production and the output increases annually,and its value-added processing becomes more and more necessary.In this paper,preparation of oligopeptides from Tilapia enzymatic hydrolysate using resins was investigated,the main results were as follows:(1)Preparation of enzymatic hydrolysate from Tilapia.The optimal technology is mixed of 5%cooked Tilapia homogenate with 2300u/g fish protein and reacted at pH 8.0 and 55℃for 4h, the undissolved solids in the slurries were removed by centrifugation.Under this enzymatic condition,the average degree of hydrolysis(DH) is 17.86%.(2)Removal of free amino acids from the enzymatic hydrolysate.Amino acids were separated from the enzymatic hydrolysate using cation exchange resin 732.The adsorption condition of free amino acids by cation exchange chromatography was pH3.0 and the flow rate kept at 1mL/min;amino acids were desorbed with 1mol/L NaOH at elution rate 1mL/min.The changes of remaining protein(or polypeptides),amino acids content and average hydrolysis degree in the eluant showed that cation exchange resin 732 had high capacity for adsorbing free amino acids but not for peptide.The adsorption for free amino acids accounts for 82.16%but only 36.30%for peptides.However,there was no significance between the average hydrolysis degree changes.Apart from free amino acids,some small molecular peptides which have high percentage of alkaline amino acids were also eluted by 1mol/L NaOH.The elution rate was 78.07%.(3)Seperation of oligopeptides.Static exchange experiment indicated that macroporous resin AB-8 effectively adsorbed oligopeptides from free amino acids-removed enzymatic hydrolysate. The condition for macroporous resin chromatography was optimized by analyzing the changes of oligopeptides ultraviolet adsorption,amino nitrogen content,average hydrolysis degree,average peptide chain length,fischer ratio and ion chromatogram.The purified enzymatic hydrolysate was passed through the column directly and the flow rate kept at 1mL/min;oligopeptides were eluted with 5%ethanol at 1mL/min.Oligopeptides with average peptide chain length from 1.18 to 6.43 were obtained.However,the ultraviolet spectrum and amino acid analysis of oligopeptides showed that the oligopeptide contains more than 6 kinds of amino acids,indicating that the products were not highly purified.更多还原