Effects of broiler weight and strain on skin collagen characteristics and their applicability for co-extruded sausage casings

For centuries people around the world enjoyed traditional sausages made from meat stuffed into natural casings. An alternative new technology is to extrude collagen gel, originating from bovine hides, directly onto the product and later cross-link it. Collagen producers are searching for other sources and consequently they are interested in factors influencing extracted collagen quality. One of the alternative sources is chicken skin, where extracted collagen properties have been shown to be influenced by the age of the chickens. In this study, the biochemical and physical properties of chicken skin collagen preparations from two different broiler strains (slow and fast-growing) and two different weights (1.6 and 2.2 kg) were investigated. Rheological measurements showed for all dispersions a decrease in elasticity at 40 °C. Differential Scanning Calorimetry (DSC) measurements of the dispersions showed T_onset ranging from 38.7° to 39.1°C. After salt precipitation, the T_onset increased to 50.1 – 55.9 °C. Mechanical strength of the films from fast and slow growing chickens ranged from 63 to 67 KPa and 53–57 KPa, respectively. Considering the biochemical and physical properties, all four chicken collagen dispersions have the potential of being a suitable collagen source for the co-extrusion process of sausages.