【作者】 徐凤香；

【导师】 高昕；

【作者基本信息】 中国海洋大学 ， 水产品加工及贮藏工程， 2007， 硕士

【摘要】 鱼翅自古以来是我国传统的名贵海珍品之一,其药用、营养价值很高。本文选用牙拣翅原翅（尾鳍）为原料,主要针对鱼翅如下几个方面进行了研究:1.在对牙拣翅原翅营养成份测定的基础上,对其加工过程中的质构特征变化进行了研究。结果表明:牙拣翅原翅经冷水浸泡回软处理,水分含量为54%;粗蛋白含量45%左右,胶原蛋白含量为41.5%（占粗蛋白总量的92%）;脂肪及灰分含量较少。原翅中含有多种氨基酸,必需氨基酸含量较高,占氨基酸总量的20.5%。原翅经浸泡回软、60℃刮砂处理后,经过蒸煮处理,组织构造及物性学参数发生明显变化,蒸煮前,结构致密、较均匀;当蒸煮至3h时,翅针结构整体结构较完整,但筋肉间出现空隙,表明胶原蛋白凝胶化形成,而蒸煮至5h时,鱼翅结构变化更加明显,空隙面积和数量增加,物性学测定结果表明,随着蒸煮时间的延长,鱼翅的各物性学参数（凝胶强度、最大破断应变、剪切应力、破断强度）变化总体呈减小趋势,蒸煮3小时后,趋于稳定,综合感官评定结果得出:牙拣翅原翅经过3h蒸煮可达到理想的质构效果。2.研究了牙拣翅胶原蛋白的抗氧化活性。分别对牙拣翅原翅翅针、骨、皮胶原蛋白进行提取、分离纯化和定性分析,并测定了其抗氧化活性。结果表明:翅针胶原蛋白、鱼皮胶原蛋白可直接用酸提取,而鱼骨胶原蛋白必需添加胃蛋白酶才能获得;翅针胶原蛋白的紫外吸收波长为230nm,热变性温度为66.7℃,SDS-page凝胶电泳分析可知其为拟弹性蛋白[α₁（E）]₃;而皮中主要为I型胶原蛋白,即[α₁（Ⅰ）]₂α₂,骨中主要为Ⅱ型胶原蛋白,即[α₁（Ⅱ）]₃。1)抑制O₂^-·活性对翅针酶解,胃蛋白酶效果最好,其酶解物抑制O₂^-·的IC₅₀值为1.87mg/mL,而对鱼皮胶原蛋白的酶解,低温碱性蛋白酶最好,IC₅₀值为2.14 mg/mL。翅针清除O₂^-·的活性优于鱼皮胶原蛋白。2)抑制·OH活性低温碱性蛋白酶活性最好,其次为胰蛋白酶,胃蛋白酶酶解物抑制活性最差;翅针蛋白酶解物(IC₅₀值为0.67mg/mL)抑制·OH活性明显低于鱼皮胶原蛋白酶解物(IC₅₀值为0.35mg/mL)。3.研究了牙拣翅粘多糖的抗氧化活性。采用双酶法提取牙拣翅翅针、软骨中的粘多糖,测得粗提物中多糖含量分别为18.18%、36.49%,硫酸根含量分别为11.79%、1.25%,翅针中多糖分子量组成分别为67.4kDa,22.6kDa,5.2kDa,3.6kDa,其中5.2kDa,3.6kDa为主要组分,其含量比约为1:2,分子量在11.9kDa¹73.6kDa之间的组分含量较少;软骨粘多糖组分的分子量依次为60.4kDa,4.6kDa,3.1kDa,分子量在11.9kDa¹73.6kDa之间组分含量多,约占总糖量的40%左右。从单糖组成上看,翅针粘多糖主要由氨基糖和糖醛酸组成,几乎不含中性糖;而软骨中单糖由糖醛酸、氨基糖和中性糖组成。软骨粘多糖对·OH的半数抑制率为0.267mg/mL;对O₂^-·的半数抑制率(IC₅₀)为1.75 mg/mL。与软骨粘多糖相比较,翅针粘多糖的抗氧化活性较差,它对·OH的抑制率与浓度相关性不明显,对O₂^-·的抑制率虽然随着浓度的增高而增大,但抑制活性较差。更多还原

【Abstract】 Shark fin, which has many medical and nutritional functions, is one of precious seafood in China. In this paper, the shark caudal fin was chosen as the material and the following researches were carried out.Firstly, the basic composition and the changes of the texture of shark fin during processing were studied. The results were shown that the shark fin is composed of 54% water, 45% protein, 41.5% collagen （92% of total protein） and a little fat and ash. Shark fin had abundant of amino acids, especially the necessary amino acids which accounted for 20.5% of total amino acids. When boiled for different time, the structure of the shark fin changed greatly, gel strength, biggest strain, shear and rupture strength of shark fin were decreased with the boiling time. After boiled three hours, such changes became little. Combined with the sensory analysis and rheological results, 3 hours boiling was a practical treatment for a perfect texture of shark fin.Secondly, the antioxidation of shark fin collagen was studied. Denatured temperature of collagen was 66.7℃. The results of UV absorption wave showed that shark sting collagen was 230nm, shark skin collagen was 234nm. Type E （[α₁（E）]₃）of Sting collagen , type I of skin collagen, and typeⅡ（[α₁（Ⅱ）]₃） of cartilage collagen was demonstrated by SDS-PAGE. The antioxidation abilities of collagen proteinase hydrolysates were investigated and the results were shown as follows:1) Inhibition ability to superoxide radical. There is the highest inhibition ability to superoxide radical of hydrolysates from shark sting by Pepsin, the value of its IC₅₀ is 1.87mg/mL. Low temperature alkaline proteinase is suitable for the hydrolysis for shark skin collagen, and the IC₅₀ was 2.14 mg/mL.2) Inhibition ability to hydroxyl radical. The hydrolysate by low temperature alkaline proteinase has the highest inhibition to hydroxyl radical, and the hydrolysate by pepsin is the lowest. The IC₅₀ of shark sting was 0.67mg/mL, much bigger than that of shark skin（0.35mg/mL）. Finally, the antioxidation of mucopolysaccharides extracted from shark fin rays and shark fin cartilage was studied. The mucopolysaccharides contents of hydrolysate were 18.18% and 36.49%, and the sulfuric acid contents were 11.79% and 1.25%. The molecular weights of mucopolysaccharides extracted from shark sting were 67.4kDa22.6kDa,5.2kDa,3.6kDa, while the molecular weights of mucopolysacch -arides extracted from shark cartilage were 60.4kDa,4.6kDa,3.1kDa. Shark fin rays were made of amino sugars and uronic acids, while shark fin cartilage was made of amino sugars, uronic acids and neural sugars.The IC₅₀ of mucopolysaccharides extracted from shark fin cartilage to remove hydroxyl radical was 0.267mg/mL, while it was 1.75 mg/mL to remove superoxide radical. Antioxidation of mucopolysaccharides extracted from shark sting was not as good as that extracted from shark cartilage.更多还原