Gastric.juice contains three substances: hydrochloric acid, enzyme pepsin and mucus. Their functions are:
(i) Hydrochloric acid in the stomach is used to make the medium acidic to facilitate the action of the enzyme pepsin and to kill germs if any.
(ii) Enzyme pepsin digests proteins to convert them into peptones.
(iii) The mucus helps to protect the stomach wall from its own secretions of hyclrochloric acid.
