Microstructural and textural investigation of various manufactured collagen sausage casings

The texture and microstructure of four commercially manufactured collagen casings and a natural sheep casing (all 23 mm diameter) were examined using shear, puncture, burst, and light transmission tests, as well as light microscopy. Shear force values were significantly higher for uncooked and cooked sausages prepared from natural sheep casing and one of the manufactured collagen casings ('processed sausage' casing) than those of 'tender breakfast' and 'European wiener' casings. For all five casings, the distance to shear uncooked sausages was greater than the distance to shear cooked sausages. Overall, it took more force to shear uncooked sausages widthwise than lengthwise regardless of the type of casing. This phenomenon was not seen to the same extent in the cooked sausage products. There was a strong correlation (R2 = 0.94) between the force to puncture and the pressure to burst wet and dry unstuffed casings. The casing for 'processed sausage' best mimicked the light transmission of the natural sheep casing. The fibres in the manufactured collagen casings were easily visible by polarized light under the light microscope.

► Evaluated texture and microstructure of manufactured collagen and natural sheep sausage casings. ► Compared uncooked and cooked stuffed casings and wet and dry unstuffed casings. ► Sheep casing was more elastic than manufactured collagen casings. ► More force was needed to shear uncooked sausages widthwise than lengthwise for all casing types.