Development and characterization of gelatin films derived from camel skin: effects of camel age and plasticizes

Abstract

Camel skin gelatin films (CSGFs) plasticized with glycerol or sorbitol were developed and evaluated. The camel (Camelus dromedarius) skin gelatins used in this study were extracted from the skins of three different camels aged 2.5, 4.5, and 7 years. The developed films plasticized with 33% glycerol and 75% sorbitol (w/w) were evaluated for their thickness, light absorption, solubility, moisture sorption–desorption isotherm, water vapor permeability (WVP), and mechanical and thermal properties. The results revealed that the camel age and the plasticizer used had significant (P < 0.05) effects on the film properties. The tensile strength values for all films ranged from 2.02 ± 0.26 MPa to 12.59 ± 2.06 MPa, and the elongation at break values ranged from 1.97 ± 0.45% to 154.92 ± 14.44%. The film color showed that the lightness values ranged from 14.26 ± 0.77 to 50.48 ± 4.66. The films plasticized with glycerol or sorbitol were 100% water soluble. The moisture sorption isotherm values increased with the increase in temperature (25 °C, 35 °C, and 45 °C). The sorbitol-plasticized films retained less water compared with the films plasticized with glycerol. In addition, the WVP values were lower in the older-skin CSGFs. The highest values of the WVP were noticed in the films (CSGF-2.5Y) with glycerol, followed by those with sorbitol (CSGF-4.5Y). Other film properties were obtained using methods such as thermal analysis by differential scanning calorimetry. The findings suggest that such films are suitable for applications in food packaging, coatings, and pharmaceutical materials.