【作者】 位绍红；

【导师】 许永安； 陈丽娇；

【作者基本信息】 福建农林大学 ， 水产品加工及贮藏工程， 2008， 硕士

【摘要】 罗非鱼是近年来国内养殖的主要经济鱼种,2004年我国罗非鱼产量89.9万吨,其加工也得到了较快的发展,2005年,我国罗非鱼出口达10.7万吨,其下脚料鱼皮、鱼鳞据测算高达2万吨左右。这些鱼皮和鱼鳞中含有丰富的胶原蛋白,是制取优质明胶的一种不可多得的价廉原料。明胶是胶原蛋白经过适度降解变性而得到的产物,其主要提取工序包括前处理、漂白及熬胶。本研究以罗非鱼鱼皮和鱼鳞为原料,通过预实验,分别以目前明胶常用的5种前处理方法(碱法,酸法,酸盐法,盐碱法,酶法)进行正交试验,通过测定鱼皮、鱼鳞的明胶得率、粘度及凝胶强度,采用正交试验的直观分析和综合平衡法,分别得出鱼皮、鱼鳞这5种前处理方法的优化工艺。然后再通过对5种前处理方法的提胶优化工艺进行比较,分别得出鱼皮、鱼鳞最佳的前处理方法。接着,通过对鱼皮进行氧化还原漂白正交试验,得出鱼皮漂白的优化工艺。最后通过对鱼皮、鱼鳞提胶pH的单因素试验、温度和时间组合优化试验,分别得出鱼皮、鱼鳞最佳的熬胶工艺。最终得出鱼皮、鱼鳞最佳的提取工艺如下:罗非鱼鱼皮提取明胶的最佳提取工艺:前处理采用酶法,用0.2%的混合酶溶液,盐酸调pH值至3.5,于40℃水浴中酶解鱼皮1h;漂白工艺采用高锰酸钾—草酸组合的氧化还原漂白方法,先用6%高锰酸钾溶液进行氧化漂白3h,然后再用1.5%草酸溶液进行还原漂白45min,之后用清水清洗至pH5-6左右;熬胶的初始pH值为5-6,熬胶分3次进行,即60℃、65℃、70℃各加热2h,过滤后将3次胶液合并,浓缩干燥。在此条件下所得明胶得率可达22.25%,勃式粘度为5.17 mPa.s,凝胶强度为271 Bloom g,透明度为100mm。罗非鱼鱼鳞提取明胶的最佳提取工艺:前处理采用酶法,用0.2%的混合酶溶液,盐酸调pH至3.5,于35℃水浴中酶解鱼鳞1h;然后用2%盐酸浸渍约4h,之后用清水清洗至pH5-6左右;熬胶的初始pH值为5-6,分3次进行,即65℃加热3h,70℃、75℃各加热3.5h,过滤后将3次胶液合并,浓缩干燥。在此条件下所得明胶得率可达13.23%,勃式粘度为8.07 mPa.s,凝胶强度为324.5Bloom g,透明度为345mm。本实验还分别测定了鱼皮胶和鱼鳞胶的理化性质,所测项目均达到国家食用明胶标准GB 6783—94。更多还原

【Abstract】 In recent years the tilapia is the main economic fish species which is cultured in China.In 2004,our country,s tilapia yields reached 899,000 tons,and its process has developed quickly.The export of our country,s tilapia reached 107,000 tons in 2005. According to the estimation,the fishskin and fish scale reached about 20,000 tons which are from the offals of tilapia,s process.Because these fishskin and fish scale contain abundant collagen,they are a kind of low price and valuable material which can be used to produce high-quality gelatin.Gelatin is the production of collagen by moderate degradation and denatur alization.The major extracting craft includes preceding process,bleaching and ext racting the gelatin with water-bath.This research study used the fishskin and fis h scale of tilapia as the raw material.after preparing experiment,respectively pe rformed orthogonal test with alkaline,acid,acid and saline,saline and alkaline,enz yme.By direct-viewing analysising and Overall balancing with orthogonal test,th e gain rate,viscosity and the bloom value of gelatin were mensurated to respe ctively obtain five optimal preceding process of fishskin and fish scale.Five kin d of preceding process of fishskin and fish scale under the single optimum co ndition were analyzed and compared to obtain the respective optimal craft.Then the optimal craft of fishskin bleaching was obtained through orthogonal test.Fi nally,the pH single factor experiment,temperature and time combinative optim ization experiment were performed to obtain the optimal craft of extracting gel atin from fishskin and fish scale.The results are as follows:The best extracting craft with tilapia fishskin is as following:preceding process for fishskin adopts enzyme,concentration 0.2%compound enzyme solution,the original pH value is 3.5,reactive temperature 40℃and time 1h.The bleaching craft uses potassium permanganate-oxalic acid combination method,by oxidation bleaching carrying on 3h with 6%potassium permanganate solution and later deoxidization bleaching carrying on 45 minutes with 1.5%oxalic acid solution,afterward clean fishskin to pH5-6 or so.The original pH value of extracting gelatin is about 5-6.The extracting gelatin is divided 3 times to carry on,the temperature 60℃→65℃→70℃,every heating time 2h,filtrate,unite percolate,concentrate and dry.In the optimal condition the gelatin gain rate could reach 22.25%,viscosity could reach 5.17 mPa.s,the bloom value could reach 271 Bloom g and diaphaneity could reach 100mm.The best extracting craft with tilapia fish scale is as following:preceding process for fish scale adopts enzyme,concentration 0.2%compound enzyme solution,the original pH value is 3.5,reactive temperature 35℃and time 1h.Clean fish scale to pH5-6 or so after soakaging 4h with 2%hydrochloric acid.The extracting gelatin is divided 3 times to carry on,heat 3h at 65℃,heat 3.5h at 70℃and heat 3.5h at 75℃,filtrate,unite percolate,concentrate and dry.In the optimal condition the gelatin gain rate could reach 13.23%,viscosity could reach 8.07mPa.s,the bloom value could reach 324.5Bloom g and diaphaneity could reach 345mm.In addition this study mensurated the physical and chemical properties of gelatin from fishskin and fish scale.The items all reached the standard for Chinese edible gelatin GB 6783—94.更多还原