Food-grade gelatin from camel skin: Extraction, characterisation and potential use for thin film packaging preparation

The present study aims on the extraction of gelatin from camel skin as a tool of agro-food by-products valorization. The extraction was performed through different methods, and the resulting gelatins served as biomaterial for edible films' preparation. The results showed that Pepsin (P) pre-treatment increased the yield of gelatin extraction to reach 34 and 38%, at 70 and 90 C-o, respectively, while it affected the molecular weight and amino acid composition, especially when the P-treatment was coupled with a high temperature (90 C-o) in the extraction process. Nevertheless, gelatin extracted without pepsin at 70 C-o (G70) showed the highest level of Gly, Pro and Hyp (530 residues/1000), reflecting its high polymerisation, compared to the other gelatins. Then, the extracted gelatins (G70, G90, G70-P and G90-P) were used for the preparation of thin films (similar to 60 mu m), named F-G70, FG90, F-G70-P and F-G90-P, respectively. Films possessed differences in the structural and techno-functional properties depending on the gelatin used for film formation. For instance, F-G70 was the strongest film and showed the best resistance against water solubility and vapor permeation. The highest mechanical and water resistance correlated with the thermal one, where F-G70 was characterized by the highest glass temperature (Tg = 74 C-o) and this value tended to be decreased after increasing the gelatin extraction temperature and Pepsin pre-treatment. Overall, the present results proved that camel skin is a promising matrix of producing gelatinbased packaging intended for food applications.