This Citric Acid is a colorless weak organic compound, not the naturally occurring but the manufactured citric acid (MCA).
Citric acid is a natural fruit acid found in citrus fruits. Citric acid gives a characteristic sour flavor, balance the acidity and improve taste.
Citric acid is used extensively as a food and beverage additive as a preservative, acidifier, flavor enhancer and a chelating agent.
1 tsp citric acid equals to one medium fresh lemon juice.
Citric acid is also used to curdle milk in preparation of paneer: Use ½ tsp/ liter milk.