Application and assessment of extruded edible casings manufactured from pectin and gelatin/sodium alginate blends for use with breakfast pork sausage

Casings formed from pectin (PN) containing 2.5% and 5% corn oil (CO) and olive oil (OO) and gelatine/sodium alginate blends (GSAB) containing 2.5% CO and OO respectively were used for sausage manufacture. Mechanical properties and water content of casings were assessed prior to application. Following sausage manufacture, product quality and shelf-life evaluation were assessed in terms of sensory attributes, instrumental colour, moisture loss and lipid oxidation. All manufactured casings were of good quality and initially produced intact and stable sausage products. However, with time, shrinkage of products occurred where GSAB casings were used. Sensory analysis of sausages showed that PN casings were more preferred to GSAB casings for sausage manufacture. CIE colour analysis supported sensory evaluation. Water losses from sausages using GSAB casings were lower compared to sausages using PN casings due to GSAB casings having higher ability to trap and absorb water compared to PN casings. Lipid oxidation developed over time for all sausage products, however, sausages manufactured using GSAB casings containing both CO and OO at 2.5% had better oxygen barrier properties compared to sausages manufactured using PN containing the same concentration of emulsified oils. Sausages manufactured using casings containing OO were more prone to lipid oxidation than those using CO. Importantly, sausages manufactured using PN casings containing 5.0% CO were extremely stable to lipid oxidation over a six day storage period and significantly, were <1 on the TBARS numbers scale.