Mustard Oil Experiment

3.2.2.1 VISCOSITY: - Viscosity of the Mustard Oil was determined by the Brookfield viscometer. Different spindle no. (Spindle no 4 and 5) were used according to the thickness or consistency of the puree at different speeds of 10, 20, 50 and 100 rpm. Viscosity was expressed as centipoise (cps).

Viscosity was measured by following formula:

Viscosity = Dial Reading × Factor

(Centipoise)

3.2.2.2 DENSITY:-

3.2.2.3 COLOUR:- The L*, a* and b* values of the mustard oil sample was measured using the Hunter Colorimeter (Colour Quest –XE Di8). Total colour difference was calculated using the equation:

TCD= ½{(Lo-L) ²+ (Ao-A) ²+ (Bo-B) ²}

Where, TCD represents the total color change; Lo, Ao and Bo refers to reference values, i.e., colour

Analytical Importance:

The value is a measure of the amount of fatty acids, which have been liberated by hydrolysis from the glycerides due to the action of moisture, temperature and/or lipolytic enzyme lipase.

Reagents:

a) Isoprpanol

b) Phenolphthalein indicator solution: - Dissolve one gram of phenolphthalein in

100 mL of ethyl alcohol.

c) Standard aqueous potassium hydroxide or sodium hydroxide solution 0.1 or 0.5

N. The solution should be colourless and stored in a brown glass bottle. For refined oils, the strength of the alkali should be fixed to 0.1 N.

Procedure:

1. Take 5 gm sample in to erlemeyer flask

2. Then add 50 ml isopropanol

3. Then boil at hot plate

4. Then add 0.5 ml Phenophthalein

5. Then neutralize it by adding of 0.1 N Potassium Hydroxide till faint permanent colour was obtained.

Free fatty acid as oelic acid % by weight = 28.2VxN/W

Free fatty acid as lauric acid % by weight = 20.0VxN/W

Free fatty acid as ricinolic acid % by weight = 29.8VxN/W

Free fatty acid as palmitic acid % by weight =

X 1000 / wt of sample.

3.2.3.3 Iodine value:

Principle:

Iodine value (I.V) is the nomber of g of iodine absorbed per 100 g of the oil or fat, when determined using Wijs solution.The material is treated in carbon tetrachloride medium with excess of iodine monochloride in glacial acetic acid. The excess of iodine monochloride is treated with potassium iodide, and the liberated iodide is estimated by titrating with standard Na2S2O3.

Reagents:

1. Wijs solution : Dissolve 8g of iodine trichloride in 200 ml of glacial acetic acid and mix with 9g of iodine dissolved in 400 ml of glacial acetic acid.

2. 10 % Potassium iodine solution : Dissolve 10 g of potassium iodide in 90mml of water.

3. 0.1 N Na2S2O3 slution.

4. Starch indicator,freshly prepared.

Procedure:

1. Take 0.5 g sample in 250 ml glass-stoppered conical flask

2. Then add 10 ml carbon tetrachloride

3. Then add 25 ml Wijs solution

4. Then store in dark place for 1 hr

5. Then add 15 ml of 10% Potassium iodide soliution and 100 ml distilled water

6. Then titrate with 0.1 N Na2S2O3solution using starch as an indicator near end point .

7. Carry out a blank determination alongside without the