Properties of different poultry skins sources in relation to co-extruded sausage casings

Abstract

Casings are an essential component in the transformation of comminuted meat into a finished sausage. Their strength and the texture of the ground meat determine the “bite” perception when eating a sausage. Traditionally, meat has been stuffed into natural casings, but alternatives, such as cellulose and co-extruded collagen casings are emerging. Bovine hide split collagen is the primary source for co-extruded casings. However, an increase in meat products consumption puts pressure on the supply of collagen casings, and therefore producers are searching for alternatives. In this study, the properties of chicken skin collagen preparations from four types of birds [fast-growing broilers (42 d), slower-growing broilers (56 d), broiler breeders (52 wk), and laying hens (100 wk)] were investigated by biochemical, and physical analyses to obtain properties important in designing new dispersions for co-extrusion. SDS-PAGE, rheology, DSC and TNBS showed little difference in parameters between the different chicken types. However, after salt precipitation, creating strong films from the broiler breeder and laying hen skins’ dispersions was not possible. Creating films was possible with the dispersions of fast and slower-growing broiler skins, particularly after precipitation with saturated NaCl.In conclusion, chicken skin collagen from slower and fast growing broilers have the potential of being a suitable collagen source for the co-extrusion process. Overall, it was feasible to form stronger films with broiler skins than with skins of broiler breeder and laying hens. This is important as the casings’ strength dictates the initial sensory perception when eating a sausage.