Effects of Hydrocolloids on the Properties of Bovine Skin Collagen Casing Films

To study the effects of hydrocolloids on the properties of collagen casing films made from bovine skin, the cork cellulose was firstly chosen as an example. The effects of cork cellulose addition on the mechanical properties, swelling ratio, water contact angle, denaturation temperature and the like properties of collagen films were investigated. Moreover, the influences of 7 different hydrocolloids (cork cellulose, microcrystalline cellulose, bamboo cellulose, konjac gum, guar gum, hydroxypropyl methylcellulose, propylene glycol alginate) on the properties of collagen films were further analyzed. The results showed that the addition of cork cellulose could improve the tensile strength at wet state and the thermal stability, which decrease the swelling rate and heat shrinkage rate. But the transparency of film would highly decreased if the addition was that high. So optimum addition amount of cork cellulose was set at 0.5% (g/g dry weight of bovine skin). The film added with propylene glycol alginate had the lowest elongation at break of 9%, the one with konjac gum showed the highest transparency of 35, and the ones with guar gum and konjac gum showed the lowest heat shrinkage of 30%. Moreover, the mechanical properties, swelling rate, heat shrinkage and transparency of film containing microcrystalline cellulose were better than that of cork cellulose and bamboo cellulose. FTIR results showed that there were no apparent changes on the chemical bonds of films in the presence of hydrocolloids. Above all, the improvement in some given properties of bovine skin collagen casing films could be obtained by adding one of the corresponding hydrocolloids.