Acidulants

i. Lactic Acid

Lactic acid is used as acidulant in beverages like soft drinks, mineral water,carbonated fruit juice acid, pickles, jam, jellies, etc. It is also used in the manufacture of beer and wine, and dairy products like paneer, casein, chhana, processed cheese, unsalted butter and in processing of meat, egg whites and sauces of canned fish.

Purity

Weigh accurately a portion of the sample equivalent to 5 g of lactic acid, transfer to a 250 ml flask, add 50 ml of 1N NaOH, mix and boil for 20 min. Add phenolphthalein (Dissolve 0.2 g of phenolphthalein in 60 ml of 90 percent ethanol and add water to make 100 ml), and titrate the excess alkali in the hot solution with 1N sulphuric acid, and perform a blank determination. Each ml of 1N NaOH is equivalent to 90.08 mg of lactic acid.

ii. Phosphoric Acid

Purity

Weigh 1 g of phosphoric acid into a glass stoppered flask, dilute with about 100 ml of water, and add 0.5 ml of thymolphthalein solution (Dissolve 0.1 g of thymolphthalein in 100 ml of ethanol and filter, if necessary.) Titrate with 1N  NaOH. Each ml of 1N NaOH is equivalent to 0.049 g of H3PO4.

iii. Citric Acid

Citric acid is used as an antioxidant, synergist, sequesterant, acidulant and flavouring agent. Its use has been permitted in the PFA rules.

Purity

Dissolve about 3 g of the accurately weighed sample in 40 ml of water. Add phenolphthalein (1 g in 100 ml alcohol) and titrate with 1N NaOH. Each ml of 1N NaOH is equivalent to 64.04 mg of citric acid