Optimization of Papain Hydrolysis Conditions for Release of Glycosaminoglycans from the Chicken Keel Cartilage

Glycosaminoglycans (GAGs) are natural biocompounds which join to construct cartilage tissuses, it can be extracted from cartilage of sharks, pigs, cows, chickens, etc. GAGs contain a Chondroitin sulfate (CS) content which is a supplement of functional food used for preventing and supporting treatment of arthritis and eye diseases. Therefore, the GAGs extraction from byproducts of the industry of cattle and poultry slaughter to identify the CS content by papain enzyme is necessary. In this study, the optimal hydrolysis conditions were obtained by response surface methodology (RSM). The independent variables were coded as: pH (x1), enzyme concentration (x2), incubation temperature (x3) and hydrolysis time (x4). The results of the analysis of variance (ANOVA) shown that the variables actively affected GAGs content. The optimal conditions of hydrolysis were derived at pH of 7.1, ratio of enzyme per substances of 0.62% w/wpo, temperature of 65 degrees C and hydrolysis time of 230 minutes, GAGs content reached 14.3% of the dry matter of raw material. Analyzes by HPLC revealed that 56.17% of the dry preparations of GAGs were CS compound, were equivalent to 8.11% of the dry matter of chicken keel cartilage. Molecular weight of the dry preparations GAGs was 259.6 kDa. The dry preparations included the contents of moisture 12.2%, protein 8.42%, lipid 0%, ash 10.03% and extracted GAGs 69.35%.