Fish oil was extracted from Tilapia byproduct by hydrolysis,regarding the extraction rate of crude fish oil as the experimental indexes.The optimum Alcalase hydrolysis condition was studied by using orthogonal experiment.The results showed the following optimal conditions:collagen was heated directly for 2 h at pH 7.5 and 55℃by added alcalase enzyme 1 750 U/g of collagen(solid to liquid was 1:2).Under these conditions extraction rate offish oil was 12.56%.the sentry evaluation was carried and the physical and chemical indicators are conducted of fish oil extracted.The results show that the crude fish oil with light fishiness was reddish brown and slightly turbid.Water and volatile matter concentration was 0.42%.The acid value of fish oil extracted was 9.29 mg/g,the peroxide value of fish oil was 8.35 mmol/kg.The iodine value was 135.87 g/(100 g).The impurity content was 0.32%.The physics and chemistry indexes achieved to the second crude fish oil in standard specifications of the aquatic products.

为牟取暴利经营者在水发水产品在加工过程中,往往加入国家明令禁止的非食品添加剂改变水发水产品的外观,诱引消费者购买,不仅损害了消费者的利益,对消费者的健康也构成了威胁。水发水产品的主要不合格项为:甲醛超标、重金属超标、pH值过高、双氧水超标,消费者可以通过感官"看、闻、摸、尝"和一些简易的化学方法来鉴别,从而维护自身利益。

The invention discloses a method for extracting crude fish oil in leftovers of tilapia. The method includes the following steps that at first, the leftovers of the processed tilapia are cleaned and minced after gall bladders are cleared out, and put into an enzymatic vessel, and then Alcalase enzyme and trypsinase are added step by step into the enzymatic vessel for enzymolysis; after the enzymolysis, the enzymatic hydrolysate is centrifuged to produce crude fish oil I; the centrifuged emulsion is frozen, thawed, demulsified, and centrifuged for the second time to produce crude fish oil II. The invention decomposes the protein of the tilapia leftovers by protease, releases fat from protein and degrades the protein combining emulsion with fat and produced in the enzymolysis process; the invention is also combined with the freezing, thawing and emulsion breaking technology, improving the crude fish oil extraction rate of tilapia and the added value of the product.

<正>在我国南方两广地区,每年冬季气温会降至5℃左右并且维持3～4个月,这段时间有大量的鱼种、成鱼和亲鱼需要越冬,历年越冬均有一定的死亡发生,给养殖生产带来了巨大损失。造成鱼类越冬死亡的原因很多,除遗传因素、水质因素外,由于营养失衡而造成鱼类免