Combined Effect of Impregnation with an Origanum vulgare Infusion and Osmotic Treatment on the Shelf Life and Quality of Chilled Chicken Fillets

The scope of this work is the study of a combined process including a dipping step into an oregano (Origanum vulgare ssp. hirtum) infusion (OV) followed by osmotic treatment of chicken fillets at 15 °C. Chicken fillets were immersed in an osmotic solution consisting of 40% glycerol and 5% NaCl with (OV/OD) and without (OD) prior antioxidant enrichment in a hypotonic oregano solution. A comparative shelf life study of all the samples (untreated, OD and OV/OD treated) was then conducted at 4 °C in order to assess the impact of this process on the quality and shelf life of chilled chicken fillets. Microbial growth, lipid oxidation and color/texture changes were measured throughout the chilled storage period. Rates of microbial growth of pretreated fillets were significantly reduced, mainly as a result of water activity decrease (OD step). Rancidity development closely related to off odors and sensory rejection was greatly inhibited in treated fillets owing to both inhibitory factors (OD and OV), with water-soluble phenols (OV step) exhibiting the main antioxidant effect. Shelf life of treated chicken fillets exhibited a more than three-fold increase as compared to the untreated samples based on both chemical and microbial spoilage indices, maintaining a positive and pleasant sensory profile throughout the storage period examined.