Main digestive function occurring in the stomach?

The main digestive function occurring in the stomach is protein digestion. The stomach is a muscular organ that secretes gastric juice, which contains hydrochloric acid and the enzyme pepsin. Hydrochloric acid creates an acidic environment in the stomach, which kills bacteria and denatures proteins, making them more susceptible to digestion by pepsin. Pepsin is a protease that breaks down proteins into smaller peptides, initiating the process of protein digestion.