Question

What are the official AOAC methods for determining the saponification value and acid value of cooking oils?

Answer 1

for the determination of the saponification value:

In this case, it is done by refluxing with a known excess of alcoholic potassium hydroxide solution. The alkali required for saponification is determined by titration of the excess potassium OH- with standard hydrochloric acid.

Calculation:

Saponification Value = 56.1 (B-S)N W

B = Volume(ml) of standard hydrochloric acid required for the blank.

s = Volume(ml) of standard hydrochloric acid required for the sample

N = Normality of the standard HCl and

W = Weight(g) of the oil/fat taken for the test

Determination of Acid Value :

The acid value is determined by directly titrating the oil/fat in an alcoholic medium against the standard potassium hydroxide/sodium hydroxide solution.

Calculation:

Acid value = 56.1VN W

here V = Volume(ml) of standard potassium hydroxide or sodium hydroxide used

N = Normality of the KOH solution or Sodium hydroxide solution; and

W = Weight(g)of the sample

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