The Research On Gelatin From Channel Catfish's Head

This paper studies the process of extracting gelatin from Channel Catfish head,and it's physico-chemical characters.First,Channel Catfish head bone is enzymohydrolysed with alkaline protease on the following conditions:pH 9.0,at the temperature of 50^C,Channel Catfish head:water = 1:1(g/mL),the enzyme is 680 U / g,oscillate frequency = 152 r / min.The white Channel Catfish head bone is obtained through zymohydrolysis,then milled to less than 0.5 mm in diameter.And then the bone is desalted with HCl on the best conditions as follows:HCl concentration = 0.4 mol / L,desalt temperature=20℃,head bone:HCl=1:5(g/mL),stirring speed =130 r/min,1.5 h exchange acidulation solution for each time and 5 times in all.After desalting comes liming,lime is treated by 0.9%Ca(OH)₂,lime water:head bone= 5:1(mL/g),liming time is 144 h in all.During this process,the magnetic stirrer is used to stir at the interval of 6 h,30 min for each time.After that,gelatin is extracted by three steps,the respective conditions are as follows:1.the first gelatin:extracting temperature 75℃,pH 4.0,stirring speed 70 r / min, extracting time 4h;2.the second gelatin:extracting temperature 82.5℃,pH 2.5,stirring speed 110 r / min, extracting time 2 h;3.the third gelatin:extracting temperature 90℃,pH 3.0,stirring speed 110 r / min, extracting time 3 h.During the first,second and third gelatin extracting,the distilled water added is the same:4 times the amount of the head bone(v/m).The 1st,2nd,3rd gelatin's rate are respectively: 3.95%,5.54%and 8.43%;gel strength are:282.3,209.7 and 117.8 Bloom;the respective viscosity are:0.29,2.81 and 4.95 mPa.s^-1.The gelatin extracted from Channel catfish head is compared with the given Pigskin gelatin's gel strength in terms of viscosity,Infrared structure The result shows that the extracted gelatin's Bloom gel strength and viscosity are higher than the given pigskin gelatin by 46.4 Bloom and 4.02 mPa.s^-1;Gelatin extracted from Channel Catfish head has similar Infrared structure to the sample gelatin.The Channel catfish head bone gelatin is used in the clarification of apple juice.It is at 25℃,the use of 0.1%gelatin to clarify apple juice 75 min can help increase Apple juice's transmittance from 29.7%to 100.0%,while reducing absorption from 2.993 to 1.730.The clarification effect was very significant.Moreover,before and after clarification with gelatin, the nutritional components of apple juice changes little except that Vitamin C changes more than 10%.The test proves that Channel Catfish head bone gelatin can be used in the industrial production of apple juice.This research provides a theoretical basis for extracting gelatin from the Channel Catfish head.It not only offers a new method for the comprehensive use of Channel fish head,but also provides a new source of raw materials for gelatin production industry.