Sequential extraction and characterization of gelatin from turkey (Meleagris gallopavo) feet.

Gelatin is a high molecular weight polypeptide that can be extracted not only from conventional sources such as hide, skins, and bones but also from the abundant collagen-rich by-products and wastes generated by industrial activities, such as poultry slaughterhouses. In this study, turkey feet were pretreated in a 3 M acetic acid solution and sequentially extracted in warm water at 55 °C, 65 °C, and 72 °C. The extracted gelatins were characterized based on their physicochemical properties, FTIR spectra, thermogravimetric and derivative analysis, molecular weight profile, bloom strength, and amino acid profile. Extraction yields ranged from 0.02 to 10.41%, totaling 15.14% after the three stages. Gelatin extracted in the first stage exhibited the most favorable characteristics, including a protein content of 77.58%, ash content of 15.13%, pH of 4.3, molecular weight distribution concentrated around 250 and 100 kDa, a bloom strength of 17.2 g, and amino acids (Hyp + Pro) content of 10.45%. The FTIR spectra indicated the presence of characteristic gelatin amides (A, B, I, II, and III) in all samples. Additionally, thermogravimetric analysis indicated that the degradation temperatures of the gelatins exceeded 300 °C. Overall, our findings suggest that turkey feet can be a promising raw material for gelatin extraction. This can minimize the waste of industrial by-products from turkey meat and generate extra income for processing industries, contributing to the concept of a circular economy. [ABSTRACT FROM AUTHOR]