Aims: As a polycation polysaccharide, chitosan is produced by deacetylation of chitin. Chitosan is a non-toxic, decomposable, and biocompatible substance that has antimicrobial properties. The aim of this study was to investigate the effect of chitosan coating and Piper nigrum essential oil on shelf life of grass carp in modified atmosphere packaging (MAP) at the refrigerator temperature (4°C).
Materials and Methods: In this experimental study, Piper nigrum and grass carp were used. After immersion of the samples into Piper nigrum and chitosan essential oil, samples were packed with MAP. The treatments consisted of control treatment (no coating and essential oil), first treatment (0.1% essential oil), second treatment (0.5% essential oil), and third treatment (1% essential oil of Piper nigrum with chitosan coating). The chemical parameters, including peroxide value (PV), thiobarbituric acid (TBA), total volatile basic nitrogen (TVB-N), free fatty acid (FFA) and pH and total viable count (TVC) of mesophilic bacteria were evaluated at the intervals of days 0, 3, 6, 9, 12, and 15. Two-way ANOVA and least significant difference (LSD) tests were used.
Findings: Changes of pH and FFA progressively increased during the time of storage for all treatments. In all treatment, the level of PV did not exceed higher than the level of limit (mEq/kg). The lowest changes of TBA and TVB-N were related to 1% treatment of P. nigrum essential oil that were significant different with other treatments (p<0.05). TVC of the samples was significantly between treatments during storage (p<0.05).
Conclusion: The use of chitosan coating and 1% of Piper nigrum essential oil increases shelf life of grass carp fillet at refrigerator temperature to 9 days.