Estudo das condições de extração e caracterização do colágeno da pele de rã-touro (lithobates catesbeianus).

Abstract

One of the consequences inherent in the processing of frog meat is the generation of by-products, which need to be used due to their high biological value in their composition. In recent years, some studies have highlighted the use of these by-products, specifically bullfrog skin, a component that is rich in collagen, whose structure and properties are similar to collagen obtained from fish and mammals. Currently, there is great interest in collagen extraction processes and its generated peptides, since the application of this protein promotes the replacement of synthetic substances in industrial processes. Thus, the objective of this research was to carry out the process of extracting collagen from the skin of bullfrogs (Lithobates catesbeianus), and to determine the conditions for better yield, technological parameters and antioxidant properties. The execution of the experiment was divided into 3 distinct chapters that allowed the visualization of the frog skin recovery process, as well as the extraction of protein compounds, specifically collagen concentrates, in addition to their structural, technological and bioactive characteristics. A 2x3 factorial design was carried out, totaling 6 treatments. This experiment used pepsin and Brauzyn® concentrations of 0.2%, in three times of hydrolysis (12, 24 and 36h). It was observed that the type of enzyme, the hydrolysis time, as well as the interaction between these factors, significantly affected (p < 0.01) the parameters of yield, collagen content and degree of hydrolysis. It was found that the treatments with the highest yield were those hydrolyzed for 12 h with the enzymes pepsin and Brauzyn® (CP12 and CB12), with values of 70.46 and 64.57%, respectively. The selected treatments (CP12 and CB12) were submitted to infrared analysis (FITR), absorption capacity in water at 60ºC, absorption capacity in oil, emulsifying activity, solubility at 70°C, and antioxidant activity. The FITR analysis indicated that the collagen concentrates maintained their helical structures, while for the technological parameters there was a significant difference (p<0.05) only for the water absorption capacity and solubility of the concentrates. Regarding the antioxidant capacity only for the ABTS•+ method there was a significant difference, with CP12 with the highest antioxidant potential (2.95 μmol ETg-1) in free radical scavenging. Therefore, the inclusion of bullfrog skin collagen in food demonstrates a potential application for the food industry, due to its technological and antioxidant properties.