Effect of Zein Nanofiber Containing Barije Essential Oil on Increasing the Storage Time of shrimp (Litopenaeus vannamei) at Refrigerated Temperature (4±1 °C)

In this research, the effectiveness of zein nanofibers containing three concentrations (1, 2, and 3%, w/w) of barije essential oil was investigated to increase the shelf life of shrimp at refrigerated temperature (4±1 °C). Firstly, the minimum growth inhibitory concentration, minimum lethal concentration of Barija essential oil and the amount of inhibitory halo of nanofiber samples containing essential oil during agar diffusion test against bacteria Staphylococcus aureus and Escherichia coli were investigated. Also, the antimicrobial, physicochemical and oxidation properties of coated shrimp such as weight loss, texture, pH, peroxide and thiobarbiotic acid were evaluated. The MIC and the MBC of barija essential oil were 0.2, 0.4 and 0.5, and 1.25 µL/mL against Staphylococcus aureus and Escherichia coli bacteria, respectively. Also, the inhibition zone of the nanofiber coating containing 3% essential oil against Escherichia coli and Staphylococcus aureus bacteria were 186.22 and 280.33 mm2, respectively. Nanofibers containing 2 and 3% of barija essential oil caused a significant decrease (P<0.05) in the count of total and psychrotrophic bacteria in shrimp compared to the control. Nanofibers containing 3% barija essential oil prevented weight loss and increased pH of shrimp and preserved them in the values of 5.03 and 6.75% respectively in coated shrimp samples after 15 days of refrigerated storage. Coating was also able to improved about 5 times the reduction of tissue hardness. The coating of shrimp prevented oxidation. The overall results showed that zein nanofibers containing 3% essential oil increased the shelf life of shrimp.