Q. Determine the acidity in the given sample of honey?

This activity will help you to:

• carry out the acidity test of the given samples of honey,

• learn about the keeping quality of honey, and

• check the conformance or non-conformance of the samples to the standards for acidity.

Principle

Acidity of honey is primarily due to presence of acids such as formic acid, gluconic acid, pyruvic acid, malic acid, citric acid and succinic acid. Acidity of a afresh honey is usually very low, 13 to 35 mEq/kg. Honey with acidity more than 40 mEq/kg is considered as poor in quality. Acidity is determined by titration of a known weight of honey with 0.1M Sodium hydroxide (NaOH).

Materials Required

0.1 N NaOH

Phenolphthalein indicator

Conical flask

Pipette

CO₂ free water

Procedure

Now carry out the activity following the steps enumerated herewith:

1) Take 10 g of honey sample in a ‘conical flask'.

2) Dissolve in it 75 ml of CO₂ free water (Boiling distilled water and cooling).

3) Mix thoroughly and titrate against standardized NaOH using phenolphthalein as indicator. (Add 1 ml of phenolphthalein during mixing of honey and water).

4) Observe for the change in colour to light pink.

5) Pink colour should persist for at least 10 seconds.

6) Also conduct blank titration with 85 ml of CO₂ free water and phenolphthalein indicator.