Improvement on properties of collagen casing films by aging treatment after oil coating

Abstract

Abstract Bending, folding and stretching deformations occur during processing of shirred collagen casings, resulting in greater friction. Oil coating of the casings before aging can be used to improve the flexibility and lubricity of casings. In this study, the effects of 8 different oils on the properties of collagen casing films before and after aging were studied. Soybean oil (SBO) and Long Chain Triglyceride (LCT) had the best spreading ability on collagen casing films. The SBO coated films had the highest longitudinal Young’s modulus (YM) and tensile strength (TS) values with increases of 26 % in YM and 38 % in TS after aging. Oiling and aging of films led to significant decreases in water absorption and shrinkage compared to aged films without oiling. Also, the oiled and aged films had lower wettability of water and lower average friction coefficients. FTIR and XRD analyses showed that oiling reduced the triple helical contents in collagen casing films with further reduction after aging. However, binding and cross-linking of collagen fibers with oil molecules resulted in a more compact structure that was confirmed by SEM.