Ace the NANP Board Exam 2025 – Unleash Your Natural Health Mojo!

The correct answer is acid hydrolysis, which is a key process that occurs in the stomach during digestion. This process involves the action of gastric acid, primarily hydrochloric acid, which creates an acidic environment. This acidity not only helps to denature proteins, unravelling their structures, but it also activates pepsinogen, an inactive enzyme secreted by the stomach lining, which is then converted into pepsin. Pepsin is an enzyme that efficiently breaks down proteins into smaller peptides.

In contrast, options like bacterial action are more related to fermentation and digestion processes that occur later in the digestive tract, particularly in the intestines, rather than the breakdown of proteins in the stomach. Heat processing, while it can alter the structure of proteins, is not a significant factor in the physiological process that occurs in the stomach. Oxidative stress pertains to cellular damage caused by reactive oxygen species and does not play a direct role in protein digestion.