The effect of drying temperature on mechanical properties of pig skin gelatin films

Films from three different bloom strength were prepared and dried at three different temperatures (20 degrees C, 40 degrees C and 60 degrees C) to investigate whether the differences in ordering and aggregation during film formation, under controlled drying conditions, reflect changes in their mechanical properties. Results showed that Young's modulus (E) was not significantly (p <= 0.05) influenced by the drying regime because it remained around 3.0 GPa. Film A-270 dried at 20 degrees C showed higher fracture properties when compared with the same sample dried at 40 degrees C and 60 degrees C. Brittleness followed: 60 degrees C > 40 degrees C > 20 degrees C. A-100 was sensitive to 60 degrees C because there was no formation of a continuous network. Films with higher bloom index showed improved fracture properties, it followed A-270 > A-160 > A-100. Films reflected lower degree of crystallinity (similar to 0%) as the drying temperature increased; the higher the crystallinity (similar to 33%), the better the fracture properties. Films formed at 40 degrees C and 60 degrees C showed mostly an amorphous structure.