Chitosan dipping or oregano oil treatments, singly or combined on modified atmosphere packaged chicken breast meat

Abstract

The present study examined the effect of natural antimicrobials: chitosan, oregano and their combination, on the shelf-life of modified atmosphere packaged chicken breast meat stored at 4°C. Treatments examined in the present study were the following: M (control samples stored under modified atmosphere packaging), M-O (samples treated with oregano oil 0.25% v/w, stored under MAP), M-CH (samples treated with chitosan 1.5% w/v, stored under MAP) and M-CH-O (treated with chitosan 1.5% w/v and oregano oil 0.25% v/w, stored under MAP). Treatment, M-CH-O, significantly affected mesophilic Total Plate Counts (TPC), lactic acid bacteria (LAB), Brochothrix thermosphacta, Enterobacteriaceae, Pseudomonas spp., and yeasts-moulds during the storage period. Lipid oxidation (as determined by MDA values) of control and treated chicken samples was in general low and below 0.5 mg MDA/kg, showing no oxidative rancidity during the storage period. Addition of chitosan to the chicken samples produced higher (P<0.05) lightness (L*) values as compared to the control samples. The results of this study indicate that the shelf-life of chicken fillets can be extended using, either oregano oil singly, and/or chitosan, by approximately 6 (M-O) and >15 (M-CH and M-CH-O) days. Interestingly, chitosan (M-CH) or chitosan-oregano (M-CH-O) treated chicken samples were sensorially acceptable during the entire refrigerated storage period of 21 days. It is noteworthy that the presence of chitosan in M-CH and M-CH-O samples did not negatively influence the taste of chicken samples, with M-CH samples receiving a higher score (compared to M-CH-O), probably as a result of a distinct and "spicy" lemon taste of chitosan, that was well received by the panelists. Based primarily on sensory data (taste attribute) M-CH and M-O treatments extended the shelf-life of chicken fillets by 6 days, while M-CH-O treatment resulted in a product with a shelf-life of 14 days, maintaining acceptable sensory characteristics.