The effects of Rosmarinus officinalis essential oil on the quality changes and fatty acids of Ctenopharyngodon idella

The effects of the use of essential oil of Rosmarinus officinalis on the chemical quality and fatty acids of fish fillets of Ctenopharyngodon idella were investigated during frozen storage at -18 ºC for 6 months. Fish fillets were divided into three groups; the control (C) without rosemary essential oil, the second group with 0.2 % rosemary essential oil (A) and the third with 0.4 % (v/v) rosemary essential oil (B). According to compositional analysis of the rosemary essential oil by GC-MS, the α-pinene (31.91%) and 1, 8- cineol (14.66%) were the predominant components. Results showed that there were no significant differences of protein in group C and A, but differences were seen between A and B (p<0.05). A significant decrease in lipid was obtained throughout between groups during storage (p<0.05). There were no significant differences of pH between three groups at storage periods (p>0.05). Effect of rosemary essential oil showed that the least changed fatty acids were on polyunsaturated fatty acids (PUFA), monounsaturated fatty acids (MUFA) and saturated fatty acids (SFA), respectively. Microbial results showed TVC content of fillets fish did not exceed the limit during storage period for A and B Groups (< 7 log CFU g-1). Rosemary essential oil at 0.2% and 0.4 % was effective in controlling the chemical compositions and fatty acids, but sensory attributes reveal a decreasing trend in the attributes like color, odour, taste, firmness and general acceptance for two groups (p<0.05), but group A indicated better scores than Group B at the end of the storage period.