04-02-2013, 04:18 PM
ESTIMATION OF FREE FATTY ACIDS IN PICKLE OIL FREE FATTY ACID (ACID VALUE)
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FREE FATTY ACID (ACID VALUE)
Acid value is the number of milligrams of KOH required to neutralize the free fatty acid present in one gram of the oil or fat. If the free fatty acids content of coconut oil or palm kernel oil has to be in percentage by weight, the calculation is based on the molecular weight of lauric acid.
REAGENTS:
1. Neutral alcohol: Boil ethanol, add a few drops of phenolphthalein and titrate against 0.01N NaOH.
2.0.01 and 0.1 N or KOH
PROCEDURE:
Weigh 10g of oil or melted fat, Dissolve the sample in hot 100ml of neutralised ethanol and titrate using 0.01 or 0.1N alkali using phenolphthalein as indicator. Shake vigorously during titration and keep the solution warm.
When testing oils and fats, which give dark coloured solution ,use thymolphthalein or alkali blue in place of phenolphthalein or an indicator containing 1ml of 0.01%(w/v) solution of methylene blue in water.
CALCULATION:
Acid value = ml of alkali x N of alkali x 28.4
Weight of sample (g)
PRESENCE OF MINERAL OIL (HOLDE TEST)
PROCEDURE:
The method is sensitive when the mineral oil content is 0.5% or more. To 1ml of oil or melted fat in a conical flask add 25ml of 0.5N alcoholic KOH solution. Boil under reflux for 5 min or until saponification is complete. Add 25 ml of hot distilled water. In the presence of mineral oil distinct turbidity appears.
[attachment=49590]
FREE FATTY ACID (ACID VALUE)
Acid value is the number of milligrams of KOH required to neutralize the free fatty acid present in one gram of the oil or fat. If the free fatty acids content of coconut oil or palm kernel oil has to be in percentage by weight, the calculation is based on the molecular weight of lauric acid.
REAGENTS:
1. Neutral alcohol: Boil ethanol, add a few drops of phenolphthalein and titrate against 0.01N NaOH.
2.0.01 and 0.1 N or KOH
PROCEDURE:
Weigh 10g of oil or melted fat, Dissolve the sample in hot 100ml of neutralised ethanol and titrate using 0.01 or 0.1N alkali using phenolphthalein as indicator. Shake vigorously during titration and keep the solution warm.
When testing oils and fats, which give dark coloured solution ,use thymolphthalein or alkali blue in place of phenolphthalein or an indicator containing 1ml of 0.01%(w/v) solution of methylene blue in water.
CALCULATION:
Acid value = ml of alkali x N of alkali x 28.4
Weight of sample (g)
PRESENCE OF MINERAL OIL (HOLDE TEST)
PROCEDURE:
The method is sensitive when the mineral oil content is 0.5% or more. To 1ml of oil or melted fat in a conical flask add 25ml of 0.5N alcoholic KOH solution. Boil under reflux for 5 min or until saponification is complete. Add 25 ml of hot distilled water. In the presence of mineral oil distinct turbidity appears.