| The Black-Bone Silky Fowl is a local food resource of Jiangxi province and traditional Chinese medicine, and its health-promoting values have been well known for more than one thousand years. The most special feature of Black-bone Silky Fowl is rich in melanin. Melanin is an important functional component of Black-bone Silky Fowl, which shows a wide range of biochemical activities, including antimutagenesis, delay senility, inhibition of influenza virus, freeradical-scavenging, antioxidation and etc. But because of the solubility properties of melanin, insolubility in water, acid and almost all solvents, and only dissolved in alkali solution, it is difficult to study the structure of melanin. Thus, until now people only knew the benefits of melanin, but didn’t know the mechanism. Studying the structure of melanin has great significance to expounding the mechanism of functional activities. Present studies showed that apart from PDCA and PTC A, there are proteins and lipids in the structure of melanin, but without deeper study. Therefore, amino acids and lipid composition in the structure of melanin was chosen as research object in this paper. Variety of research methods and techniques were used to study the effects of different degradation methods to kinds of product composition, yields, molecular weight distribution, volatile components, and the contents and classes of amino acids and lipids composition in degradation products.1、BSFM was degraded with oxidative degradation methods of K2CO3-H2O2, KMnO4, NaOH-H2O2and NH3·H2O-H2O2, and the water-solubility products were obtained, then the and molecular weight distribution of degradation products were analyzed. Results showed that products from different degradation methods were difference with each other. The degradation rate of KMnO4method was highest and up to82.5%, K2CO3-H2O2methods followed was61.5%, the rests were above50%. As to the molecular weight of degradation products, NH3H2O-H2O2products was the biggest up to493810.2Da, and K2CO3-H2O2followed was1572.8Da.2、BSFM was degraded with four different oxidative degradation methods, and the types of product composition in degradation products and its extracts were analyzed. Results showed that all degradation products contained organic acids but didn’t contain higher alcohols, alkaloids and phenolic composition; furthermore, there were varying degrees of amino acids, lipids, indole derivatives, reducing substances and steroidal substances in each product. Also, the types in extracts showed that hydrocarbons were major components in NaOH-H2O2degradation product, and lipids were major components in KMnO4and K2CO3-H2O2degradation products, the types of extracts in NH3·H2O-H2O2degradation products was small quantities.3、Alkalinity-H2O2methods were adopted to degrading BSFM, and the amino acids in melanin structure were analyzed. Results showed that there were lots of amino acids linked around BSFM. There was9.28%amino acids linked around melanin which was hydrolized by hydrochloric acid for one time, and the contents of leucine, aspartic acid, valine, isoleucine and proline in degradation products of this melanin were higher than that linked around the melanin. These results suggested that these amino acids existed in melanin structure.4、The effects of degradation condition of NH3·H2O-H2O2methods on the yields and molecular weight of products were investigated. We found that after8h, the yield was near to48%and tended towards stability, and there were no influence of high hydrogen peroxide dosage and pH value on the products yeilds. The molecular weight of macromolecules products was about15000Da, middle molecule was about7000Da and small molecule was about1100Da.5、The effects of degradation condition of NH3·H2O-H2O2methods on the molecular weight of products were studied. Results showed that degradation conditions had no impacts on molecular size, only had effects on the proportion of various molecular weight products:with the degradation time increased, the proportion of macromolecular products decreases, and the proportion of small molecule products increased, meanwhile the proportion of middle molecule products tended towards stability.6n A series of carbon alkanes of different length (C14～C33) were first found in the degradation products of BSFM using NaOH-H2O2degradation methods and GC/MS, this suggested that carbon alkanes may be the part of BSFM structure. 7、The effects of NaOH-H2O2degradation condition on the production of alkane composition were first studied. Results showed that the contents of alkanes were increased with the increase of H2O2dosage. When the dosage of H2O2was3.4%, alkanes components was highest. When the dosage of H2O2was4.4%, there were unsaturated hydrocarbons, alcohols, aldehydes, ketones and acids in degradation products, which may be generated due to degrading or excessive oxidation of alkanes. With the increase of degradation time, alkanes components increased, and the contents of alkanes were highest at20h.8> BSFM was degradated with of KMnO4and K2CO3-H2O2degradation methods, and the products were ectracts with ethyl acetate and chloroform, then the extracts derived by derivatization reagent was analyzed with GC/MS to study lipds in extracts. Results showed that there were large amounts of fatty acids in extracts, including octandioic acid(6.78%), nonandioic acid(6.29%), heptanedioic acid(6.22%), glutaric acid(6.22%), hexanedioic acid(5.92%), succinic acid(5.4%), hexadecanoic acid(2.76%), octadecanoic acid (2.11%) and other fatty acids. Ethyl acetate could extract fatty acids from degradation products completely, and the types of fatty acids extracted under acidic conditions were far more than that extracted under alkaline conditions.9、Cholesterol was found in BSTFA derivative of K2CO3-H2O2degradation products, this suggested that cholesterol may be an component in melanin structure or product during degradation. |
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