Gelatin from chicken feet: papain-assisted extraction, characterization and its application

Abstract

The characteristics and physico-chemical properties of gelatin from chicken feet were investigated and compared to the commercial bovine gelatin (CBG). The chicken feet gelatin was extracted by the presence of crude papain (1%, w/w) for 12 h at 37^oC. The gelatin yield was 18.4% based on dry weight basis. The obtained gelatin have protein content lower than CBG with 40.06%, as well as for moisture and fat with 7.56% and 1.13%, respectively. Extracted gelatin showed viscosity of 2.98 cp, setting point at 20^oC, and melting point at 30^oC, which is similar to CBG (30^oC). For Fourier Transform Infrared spectrum, chicken feet gelatin has almost similar peak of amide I, II, III, A and B with CBG, with 1,745.62 cm^-1 to amide I, 1,553.19 cm^-1 to amide II, 1,238.51 cm^-1 to amide III, 2,926.42 cm^-1 to amide B, and 3,322.84 cm^-1 to amide A. Chicken feet gelatin exhibited similar fat binding capacity, foaming and emulsifying properties with CBG, while slightly different for water holding capacity (p<0.05). Furthermore, the major components of extracted gelatin had the molecular weight of 130 and 143 kDa. Gelatin obtained by papain-assisted extraction showed capability as juice clarifier as indicated by lowering the guava juice turbidity. For instance, at the same concentration applied (0.16%), the turbidity of the gelatin extracted was 204 FTU, while CBG was 367 FTU.