Effect of Garlic and Coriander Essential Oils on Quality Parameters of Oreochromis niloticus Fillets

The study was assumed to verify the effect of garlic and coriander essential oils on quality parameters of fish. Deteriorative changes of fish could be occurred directly after catching, thus Seventy-five Oreochromis niloticus (O. niloticus) (150 fillet samples) were divided into five groups, with the control group being dipped in sterile distilled water, the second and third groups being dipped in garlic essential oil (GEO) 1% (w/v) and 2%, and the fourth and fifth groups being dipped in coriander essential oil (CEO) 1% (w/v) and 2%, respectively. On the sixth day of storage, the sensory analysis revealed that all treated groups were considerably (P <0.05) greater than the control. The initial pH value for all group were 6.02 ± 0.01 while on the 6th day of chilling was 6.48 ± 0.02, 6.24 ± 0.04, 6.13 ± 0.03, 6.31 ± 0.01, and 6.19 ± 0.04 in control, GEO 1%, GEO 2%, CEO 1% and CEO 2%, respectively. The Trimethylamine (TMA-N) mean values on the 6th day were 10.16± 0.21 , 6.11 ± 0.14, 3.91 ± 0.10, 7.12 ± 0.12, and 4.26 ± 0.14 mg N/100 g in control GEO 1%, GEO 2%, CEO 1% and CEO 2%, respectively. On the third and sixth days of storage, thiobarbituric acid (TBA) in the control group was substantially greater than in the treatment groups (p < 0.05). The initial counts of Staphylococcus were 5.24 ± 0.32 log10 CFU/g in the control and were reduced to 4.02 ± 0.18, 3.22 ± 0.13, 4.13 ± 0.16 and 3.35 ± 0.18 log10 CFU/g in GEO 1%, GEO 2%, CEO 1% and CEO 2%, respectively on the 6th day of chilling. The pseudomonas counts significantly reduced (p < 0.05) on the 3rd and 6th day of chilling in all treated groups in comparison with the control group. Therefore, Garlic and coriander essential oils have the ability to enhance sensory, delay spoilage parameters, reduce bacterial load in cold stored O. niloticus fillet in addition to prolong the shelf life.