The present study is aimed at evaluating the effect of functional alginate coating incorporated with Lactoperoxidase (LPOS) and Zataria multiflora Essential Oil (ZEO) or both as natural additives on microbial and chemical characteristics of rainbow trout fillets. Firstly, Different treatments of trout fillets were prepared using ZEO (0.5 and 1%) and LPOS (5%) individually and in combination. Then stored in the refrigerator for 16 days and were analyzed for chemical (pH and Total Volatiles Base-Nitrogen (TVB-N)) and microbial (Total mesophilic viable count, psychotropic count, Shewanella putrefaciens count, and Pseudomonas spp. count) characteristics at 4-day intervals. Results indicated that the combination of ZEO and LPOS had the strongest effect on chemical spoilage parameters (TVN, pH) and spoilage microbial flora of trout fillets during storage; however, samples with the individual use of ZEO or LPOS also had statistically significant (P<0.05) effects on preserving the chemical and microbial quality of trout fillets. According to the results, the application of sodium alginate coating impregnated with LPOS and ZEO especially in combination can control undesirable chemical and microbial changes of fish and extend its shelf life during refrigeration.

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