Study On The Molecular Weight Control Technology Of Hydrolyzed Collagen

Chrome shaving contains large amounts of collagen, which accounting for over90%of dry weight of chrome shaving. Extracting collagen from chromium shavings and efficiently utilizing it is the most reasonable way to deal with the tanning litter. At present, the collagen extracted from chrome shavings can be reused as synthetic retannage, greasing agents and coating agents for leather, and can also be used to produce organic fertilizers used in agriculture, to serve as toughening agent in light and paper industry. But no matter for which industry, the control of the molecular weight distribution and size of the collagen is still a problem.In this paper, take the collagen extracted from chrome shavings for study, we explore different extracting methods of controlling the distribution and size of the collagen molecular weight. Using orthogonal experiment method, we study the impact of reaction conditions of alkali, alkaline-enzyme, acid-enzyme extraction methods on molecular weight distribution and size of collagen. Using high performance liquid chromatography-multi-angle laser light scattering Hyphenated techniques to determine the molecular size of extracted collagen, the feasibility of using capillary electrophoresis instrument to measure the molecular weight distribution and size of collagen was proved.Experimental study of extraction method for controlling the collagen molecular weight indicates that collagen extracted by MgO extraction method has the maximum molecular weight, its maximum concentration molecular weight is134316Da, its maximum concentration molecular weight content is72%, and average molecular weight is115803Da. Thus MgO method can be used to control the molecular weight of collagen to be bigger than10WDa, under the same conditions of capillary electrophoresis, the use of an alkaline agent+papain extraction method can control content of extracted collagen with molecular weight over2000Da to reach61%～72%; molecular weight of collagen extracted with sulfuric acid and oxalic acid have the same distribution generally, oxalic acid extraction method can control the content of extracted collagen with molecular weight about20kD to be73.32%, acid extracted method can control the content of extracted collagen with molecular weight about15kDa to be70.44%. However, maximum content of molecular weight of collagen extracted with acid-enzymatic cannot be more than60%. In that case, oxalic acid+acid protease method can be used to extract collagen, and by orthogonal experiment under hydrolysis conditions, the distribution and size of molecular weight can be further controlled.Experimental study on the impact of collagen extraction conditions on control of molecular weight shows that in the orthogonal experiment of MgO method, the impact of reaction conditions on maximum content of molecular weight of collagen is quite small. In the orthogonal experiment of MgO+papain method, as the MgO content, the reaction time increases as well as the reaction temperature increases, the maximum content of collagen molecular weight increases firstly and then decrease. Thus, the optimal conditions to control the maximum content of molecular weight of collagen extracted with MgO+papain to be over60%is:MgO amount is3%, the reaction time is3h, the reaction temperature is80℃. In the orthogonal experiment of acid+acidic protease method, as amount of oxalic acid, the reaction time as well as reaction temperature increase, the maximum content of the molecular weight decreases. Therefore, the optimal process to control maximum content of molecular weight of collagen extracted with acid+oxalic acid to be over60%is:amount of acid is6%, the reaction time is1h, the reaction temperature is65℃.