Enhancing Chicken Fillets' Shelf Life: Synergistic Effect of Whey Protein Isolate and <i>Ziziphora clinopodioides</i> Essential Oil

Chicken filets are among the favorite and perishable proteins in the food industry. One of the impressive ways to enhance the chicken meat's shelf life is by applying suitable coatings packaging. In this study, the antimicrobial effect of whey protein isolate (WPI) coating with <i>Ziziphora clinopodioides</i> essential oil (ZEO) (0.6%, 0.8% and 1% v/v) on the microbial load, psychrotrophic bacteria, <i>Pseudomonas</i> spp., Coliform, and LAB bacteria, chemical and organoleptic properties of chicken filets were evaluated during 12 days of cold storage. The highest antimicrobial effect was observed in the sample with WPI coating containing 1% ZEO after 12 days of storage in the refrigerator. The results showed that the treated chicken filets had a slower rate of increase in microbial count compared to the control. Additionally, chicken filets coated with WPI containing 1% ZEO exhibited the lowest microbial count at the end of the storage period. Regarding chemical data, the TVB-N value in the control sample increased from 13.45 ± 2.02 to 38.21 ± 3.05 mg MDA/100 g, whereas in the samples containing WPI and 1% ZEO, it decreased to 25.23 ± 2.97 mg MDA/100 g. The pH values in chicken filet samples with WPI coating and 1% ZEO reached the lowest value (6.03 ± 0.1) during storage, while in the control sample, the pH increased to 6.47 ± 0.05. The final peroxide value in the control sample was 0.117 ± 0.01, but in the samples with WPI coating and 1% ZEO, it decreased to 0.105 ± 0.02. The WPI coating with ZEO also has positive effects on the chemical and organoleptic properties of chicken filets. The results showed that WPI with 1% ZEO could be applied for fresh chicken filets preserving with no undesirable sensory properties.