Question

Which of the following acid is present in sour milk?

• A. Lactic Acid
• B. Citric Acid
• C. Glycolic Acid
• D. Tartaric Acid

Answer 1

The correct option is A

Lactic Acid

The correct option is A

Explanation of the correct option:

1. Any substance, which tastes sour in water solution is an acid.
2. An acid changes blue litmus paper to red, reacts with bases to produce salts, and reacts with some metals to discharge hydrogen.
3. In sour milk, lactic acid is present, it is the product of the fermentation of milk sugar, that is, lactose by the bacteria Lactobacillus.
4. Lactic acid is mainly present in sour milk and other milk products like kefir, cottage cheese, yogurt, etc. The acid is primarily accountable for sour flavors.

Explanation of the incorrect option:

Option B:

1. Citric acid is a colourless weak organic acid, which is found primarily in citrus fruits.
2. Citric acid is used for cleaning purposes, as a food additive, in cosmetics, as a water softener, etc.

Option C:

1. A colourless, odourless, hygroscopic crystalline solid, which is highly soluble in water is glycolic acid.
2. It is an alpha hydroxy acid, which is found naturally in sugarcane.

Option D:

1. A white, crystalline organic acid, which occurs naturally in several fruits like grapes, bananas, citrus, and tamarinds is tartaric acid.
2. It is generally used in the manufacturing of soft drinks, and tanning leather, and provides tartness to foods.

Final answer: Lactic acid is present in sour milk.