A study on the effect of rosemary extract (Rosmarinus officinalis) on the quality of fish fingers produced from Silver carp (Hypophthalmichthys molitrix)

Plant extracts are rich sources of natural antioxidant and antibacterial compounds. In recent decades، the need for using natural antioxidants in foods، pharmaceuticals and cosmetics has promopted extensive scientific research. The purpose of this study was to investigation of effect of different percentages of rosemary extract (0، 1، 2. 5 and 5%) on the quality، chemical and microbial of the produced fish fingers from minced of silver carp. Samples were stored in the refrigerator at a temperature of 4±1°C (for 15 days). Chemical and microbial tests (parameters of pH، thiobarbitoric acid (TBA)، volatile nitrogen bases (TVN)، total bacterial count) were performed on the prepared samples during the store period. Based on the results، total bacteria counts، showed that rosemary extract has anti-bacterial properties، except 6، every day control samples compared to samples treated rosemary extract total bacterial load is more. The results showed that in samples treated with rosemary extract، pH decreased during storage significantly، this decrease is partly due to the anti-bacterial effect of rosemary extract (P<0. 05). The antioxidant properties of rosemary extracts inhibit TBA exceed acceptable limits during the maintenance period. TBA values in samples treated with rosemary extract significantly lower than the control samples from day 6 to the end of the storage period. Volatile nitrogen bases in samples treated with different concentrations of the rosemary extract (except 5%) did not exceed acceptable limit during storage period. Based on the results of this study، can be used from rosemary extract (1%) for to keep of the quality of fish finger in cold conditions for a short period.