Aquatic products are considered a rich source of vitamins, minerals, unsaturated fatty acids, and protein for humans, so it is important to develop methods to increase the shelf-life and preserve the freshness of these products. In order to produce nanofibers, gelatin solutions with concentrations of 10, 15, and 20 percent (w/v) contaning different ratios of eugenol (gelatin: eugenol 50:50, 70:30, 90:10) were prepared. The viscosity, electrical conductivity and surface tension of the solutions were measured. Then, they were electrospinned by a nozzle-less electrospinning device and process parameters including voltage, pin-collector distance and rotation speed were optimized as 13 kV, 10 cm and 30 rpm respectively. Following measurement of the efficiency and loading capacity of encapsulation, the morphology and diameter of nanofibers were investigated by a Field emission scanning electron microscopy (FESEM). In order to investigate the chemical changes and functional groups of nanofibers, a Fourier transform infrared spectrum (FTIR) was avaluated. Also, Thermal gravimetric analysis (TGA) was used to analyze the thermal profiles. The antioxidant activity of eugenol-containing nanofibers was studied using the DPPH radical method. Eugenol-containing nanofibers were used to coat the fish, before pH, drip loss, oxidation, microbial growth, color, and texture of the samples were eva‎luated during 7 days storage at 6 C˚. The results showed a high encapsulation efficiency of 97% and an increase in the loading and efficiency of encapsulation as a function of the concentration of essential oil and gelatin (P<0.05). Nanofibers obtained from gelatin/eugenol solution with a ratio of 50:50 in a 20% concentration of gelatin, with the lowest average diameter equal to 91.11 ± 25.26 nm and the highest efficiency (99.98 ± 0.14) and encapsulation efficiency (49.12 ± 0.12) were selected for further analysis. The eugenol was trapped in the nanofibers without any chemical reaction, and an increase in the thermal stability of the eugenol was observed as a result of encapsulation. Increasing gelatin concentrations and the gelatin/eugenol ratio increased the antioxidant activity (P<0.05), so that gelatin/eugenol nanofibers with a ratio of 50:50 and a concentration of 20% gelatin had the highest antioxidant activity of 75.99 ± 1.23%. The results showed that the fish fillet coated with eugenol-containing nanofibers effectively prevented the increase in pH, drip loss, texturey destruction, oxidation, microbial spoilage, and color changes in the sample. On the seventh day of storage, the amount of drip loss and pH in the uncoated were 2.3%, 7.15 and coated samples were 1.26%, 6.43, respectively. The oxidation and microbial spoilage were also higher in the uncoated sample than the coated one (P<0.05). Therefore, fish coating with gelatin nanofibers containing eugenol effectively increased the shelf life of this product during storage.

نفيسه سلطاني زاده , ميلاد فتحي

عليرضا علافچيان

اميرحسين گلي , احمد ميره اي