| Collagen was a type of poly-glycoprotein, white or ivory-white, included some galactose and gilucose. Collagen is the main protein of Extracellular Matrix(ECM), accounted for up to 85% of the weight of the collagen fibre, about 25%～30% of the weight of the total protein, and about 6% of avoirdupois. Collagen and was responsible for the resilience and elasticity of the skin. Collagen's elementary structure was "Gly-X-Y" , had about 1/3 glycin. Because of its special biological properties, for many years, injectable bovine, porcine, or polymerized collagens were safely and effectively used as a biomaterial for dermal augmentation or for the correction of dermal defects caused by aging, acne scars, or trauma, collagen were widely used in functional foods, cosmetic, beverage, plastic surgery, too.China was a superpower of pig industry, produced about 0.5 million tons pork lung per year, at present, most of it used for feeds of pig or pet, furthermore, many pork abattoirs did not recovery it at all in china, which wasted resource, polluted environment, too. Its value would increase 20～50 times at least, if used it to extract collagen.This paper determined the content of collagen in pork lung. The removing of grease and non-collagen proteins, the effect factors to extract collagen from pork lung, (Collagens, based on the preparation processes, can be divided into salt soluble collagen, acid soluble collagen, and pepsin soluble collagen. Although a few studies applied cold neutral salt solutions for collagen extraction, the soluble fraction obtained by this method has a very low collagen yield and contains a large portion of non-collagen proteins. so, in this paper only the acid process and the enzymatic method were covered.) the purification of pork lung collagen (PLC), the physical and chemical properties of PLC were studied. At present, there were not correlated report in the national and international articles and markets about PLC, this paper made up the blanks of study on PLC. The main experimental results were summarized as followings:(1) The content of total protein was 12.51%±0.41, ether extract was 3.01 %±0.20, moisture level was 83.17%±0.33, collagen was 3.08%±0.12 of pork lung in my experiment.(2) The effect of acetone, 5%sodium carbonate, 1:1aether+petroleum ether, petroleum ether on degrease were not remarkable. The conditions which remove Non-collagen proteins were: 4% NaCl solution, the ratio of raw material to acid solution was 1:8, pretreatment time was 8h.(3) To the yield , papain with citric acid to extract collagen from pork lung was the best method in these 4 methods in my experiment. The conditions to extract collagen from pork lung by papain were: 0.1mol/L citric acid, pH6.0, dose of acid protease was 1.5%(w/w), size of pork lung was controlled by mashed 80s, 10000 rpm, extraction temperature was 10℃, the ratio of raw material to acid solution was 1:15, extraction time was70h.(4) The thermal denaturation temperature of PLC was 35～40℃. The intrinsic viscosity of PLC extracted by acetic acid was 9.1dl/g, the intrinsic viscosity of PLC extracted by citric acid was 9.56dl/g, the intrinsic viscosity of PLC extracted by acid protease with acetic acid was 8.8dl/g, the intrinsic viscosity of PLC extracted by papain with citric acid was 8.56dl/g.(5) The emulsification capability and stability of PLC extracted by papain was 52.7% and 64% respectively, when the concentration of PLC solution was 0.4%. The increase of emulsification capability of PLC was remarkable, but emulsification stability of PLC was unremarkable when the concentration of PLC solution exceeded 0.2%. The emulsification capability achieved the max. 48.89% at pH6.0, the emulsification stability achieved the max.56% at pH3.0 and pH8.0.(6) The hygroscopicity of PLC extracted by papain with citric acid achieved the Max. 21.7% in R.H43% after 60h and 52.03% in R.H81% after 36h.The liquid-binding power of PLC extracted by papain with citric acid was 53.19% in R.H43% after 24h, 71.88% after 36h and 40.62% after 48h in R.H81%. Considering other properties, PLC used about in R.H81% was the best.
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