To study the effect of rapeseed & sesame oil on antioxidant activity. To study the decline in oxidation stability of Vacuum Packaged (Channa marulius) fillets under the frozen condition and enhance the sensory evaluation of fish fillet by immersing in nanoemulsion of virgin rapeseed and sesame oil.
Preparation of nano-emulsions:
To preparation nanoemulsion develop two-step procedure consisting of oil and water phase was adopted as previously described . Oil and water-based nanoemulsions (O/W) was prepared comprised on oil (rapeseed, sesame) with a concentration of 20%, 25%, glycerin (2%), and a surfactant (gelatin 3%). The oil phase components were mixed in the water phase accordingly (70, 75 %). The mixture was homogenized for 10 min after one hour. The volume of emulsion processed was 1000 ml.
Fish fillets Preparation:
Channa marulius, with an average weight of 4 – 5 kg, was purchased from the supper market (Lahore). Fish fillets preparation included cutting, gutting, skinning and filleting. The fillets were washed and divided into 5 experimental groups. Four groups were treated with different concentrations of nanoemulsion i.e., T1 (S.O 20%), T2 (S.O 25%),T3(R.O 20%), T4 (R.O 25%) and control (C) without treatment. The Channa marulius fillets were soaked (3/1, w/ v) for 30 minutes in the prepared nanoemulsions with different concentrations of rapeseed and sesame oil and immediately vaccum packed in polyamide bags. After the vacuum packing, the filets were stored at -40 oC temperature for 0, 4, 7, and 15 days for further analysis.
Free fatty acids
FFA were determined by using the titration method . Fifty milliliters of ethanol was titrated against the 0.1N solution of NaOH using 3-4 drops of 1% phenolphthalein indicator. One gram of sample was added in the flask and again titrated with 0.1N solution of NaOH till the endpoint with pink coloration. The titrant volume was noted and FFA was determined by using the following formula. FFA= Volume used in burette × 0.1 × 282 ×100/1000× sample weight
In a conical flask 2 gram sample, 1mL saturated KI and 30 mL of PV solution were added and kept in the dark for one minute. After 1 minute, 30 ml of distilled water was added along the flask walls. One milliliter of the starch solution was added to the mixture and titrated sodium thiosulphate solution till the endpoint (white color). The burette reading was used for peroxide calculation by using the following formula .
PV = Volume used × Normality used × 1000/ sample weight
Total Flavonoid Content:
The total flavonoid content of Channa marulius fillets was determined by spectrophotometric examination using rutin as standard. In a test tube fish extract (0.1 ml) and 0.2ml solution of 5% NaNO3 were mixed. After five minutes, 0.2 ml of AlCl3 and 1ml of NaOH (1 Molar) were added and the tube was incubated at room temperature for 15 min. Samples and standards was measured at 510 nm absorbance on a spectrophotometer. Total flavonoid content were reported as mg RE/g. followed by flavonoid derivatives 
Total phenol content:
The phenol contents in Channa marulius fillets were determined using the reagent folin ciocalteu .One gram of the sample was mixed with 2.5 ml folin ciocalteu (0.2 M) and 2 ml sodium carbonate (Na2CO3 7.5%) in a test tube The cyanogenic contents in extract samples were estimated by alkaline titration according to the method outlined in AOAC  and allowed to rest in the dark at 22-24oC for 10 minutes. The absorbance of the sample and standard were measured at 765 nm. Gallic acid was used as a standard. The amount of total contents in the sample were determined as mg GAE/g. .
Total Antioxidant Activity:
Total antioxidant activity of Channa marulius fillets was determined using ascorbic acid as standard. In a test tube, 0.3 gram of fish filet was mixed with 3ml of 0.6 M sulfuric acid. After adding 28mM sodium phosphate and 4mM ammonium molybdate solutions, the test tube was incubated at 85 oC for 90 minutes and absorbance was recorded at 695 nm through a spectrophotometer. Total antioxidant activity was expressed as mg Ascorbic Acid per gram. And followed by thE Nabasree method .
Sensory evaluation was conduct by 8 panelists in the sensory evaluation lab in the central lab complex UVAS Ravi Campus Pattoki.Each judge provided written Performa for sensoric evaluation. The panelists were provided informative instructions and brief definitions of attributes such as color, flavor and overall acceptability. Proficient and unexperienced evaluators carried out the sensory analysis of channa marulis fillets according to the instructions given by Meilgaard . They received a set of samples in a randomized order. The fillets were presented at room temperature served in white dishes. The various sensory attributes were analyzed: color, odor, taste, texture, and general acceptability. The panelists were provided a rank to judge the sensory properties according to sensory score 1 to 9 (extremely dislike, dislike, dislike moderately, dislike slightly, neither like nor dislike, like slightly, like moderately, like very much, extremely like) followed by Codex Guidelines.  sensoric analysis was performed at different storage intervals for experimental treatments.
Statistical analysis of the experiment was done by using SAS 9.1 version statistical package. The statistical data was analyzed in two-way analysis of variance. Means of treatment compared by Duncan multiple range tests. (P < 0.05)