Make yourself Familiar with the instrument (hover for more info)
Measuring cylinder
Conical Flask
Weighing Scale
Burner
Burette
Step 1: Select the sample
Step 1-1: Melt the solid Mixture
click to turn on hot
plate
click to place
flask
Generally fats are solid at room temperature
Step 2: Weigh 5g of oil/fat sample in conical flask
click to place flask
What is the required quantity of sample to be taken for estimation of peroxide value of oil/fat
Step 3: Add 30 ml acetic acid-chloroform solution in the sample flask and swirl to dissolve
click to pour
acid solution
In what ratio acetic acid and Chloroform solution is prepared
Step 4: Add 0.5 ml saturated KI solution and shake it for 1 min
click to suck KI
solution
Step 5: Add 30 ml distilled water
click to pour
distilled water
click to pour
distilled water
Step 6: Titrate the mixture with 0.1 N sodium thio-sulphate solution until yellow color is almost gone
0 ml
click to pour
0.1N NaOH
Step 7: Add 0.5 ml 1% starch solution
click to suck
solution
Which indicator is used in titration for estimation of peroxide value of oil/fat
Step 8: Further titrate until blue color just disappears
0 ml
Observation Table
| Selected sample | Weight of sample (g) (W) | Normality of Sodium thiosulphate solution (N) | Burette reading (ml) | Titrant used (ml) | |
|---|---|---|---|---|---|
| Initial value | Final value | ||||
| 5.0 | 0.1 | 0.0 | |||
FFA(%) =
| Peroxide value (mEq peroxide/kg) = | V x N |
|---|---|
| W | |
| Peroxide value (mEq peroxide/kg) = | x 0.1 |
| 5 | |
| Peroxide value (mEq peroxide/kg) = |
Fresh oil sample has less peroxide value than used oil which indicates its good quality and better shelf-life
Inference
The rancid oil has the peroxide value (mEq peroxide/kg) in the range of
The rancid oil has the Peroxe value in the range of 30-40 mEq/kg as per FSSAI standard.
The peroxide value of the given sample is 9.2%. So, this sample is safe for edible purposes.