Effect of food ingredients and selected lipids on the physical properties of extruded edible films/casings

Films/casings produced using pectin (PN) and gelatin/sodium alginate blends (GSAB) containing 2.5 and 5% added corn oil (CO) or olive oil (OO) and non-oil containing were manufactured using extrusion technology. Films/casings formed from PN and GSAB had great difference in properties of tensile strength, elongation, Young's modulus and puncture resistance. Quality and stability of films/casings were greatly enhanced on addition of oils. However, an oil addition of 2.5% was identified as optimal while 5% decreased the final films/casings quality. Oil addition increased (P < 0.05) films/casings thicknesses. Oil addition also decreased (P < 0.05) tensile strength, puncture resistance, Young's modulus and tear resistance of films/casings but increased their elongation properties, with the exception of converse effect of 2.5% CO on two films/casings. Olive oil and CO both reduced (P < 0.05) water vapour transfer rate (WVTR) of films/casings. However, no significant difference between films using different concentrations of oil was observed with respect to WVTR.