Nanocomposite Films Based on Soy Protein Isolate-Montmorillonite Nanoclay Containing Emulsion and Nanoemulsion of Zataria Multiflora Essential Oil for Preserving Chilled Chicken Burgers

This study aimed to evaluate the effect of nanocomposite film based on soy protein isolate-montmorillonite nanoclay (SPI-MMT) containing Zataria multiflora essential oil emulsion (ZEO) and nanoemulsion (ZNE) on the quality of chilled chicken burgers.  Nanoemulsion, nanocomposite film, and chicken burgers were prepared based on instructions. The hamburgers were divided into six different groups with four replicates. The experimental groups were Control, SPI-MMT, SPI-MMT+1% ZEO, SPI-MMT+2% ZEO, SPI-MMT+1% ZNE, and SPI-MMT+2% ZNE, which were analyzed for microbial, physicochemical, and sensory parameters during 16 days of storage at refrigerator (days include 0, 4, 8, 12, and 16).  The treated groups, including SPI-MMT+1% ZEO, SPI-MMT+2% ZEO, SPI-MMT+1% ZNE, and SPI-MMT+2% ZNE, showed the lower mesophilic and psychrophilic bacteria, lactic acid bacteria (LAB) and Enterobacteriaceae count than the control and SPI-MMT groups during storage. The treatments also reduced the increasing rate of total volatile nitrogen, lipid oxidation, pH, and cooking loss during storage. The SPI-MMT+2% ZNE treatment was the best treatment to reduce the microbial population, retard physicochemical and sensory changes, and increase the shelf-life of chicken burgers.  Based on the results, the nanocomposite film based on soy protein isolate-montmorillonite nanoclay containing Z. multiflora essential oil emulsion and nanoemulsion can improve the microbiological and physicochemical quality and is recommended for the preservation of chicken burgers during chilled storage.