Final answer:
Pepsin functions optimally in the stomach at a low pH of around 1.5, where it helps break down proteins. The FDA ordered fortification of all enriched grain products with an absorbable synthetic form of folate-folic acid. This means that manufacturers of grain products must add this form of folate to their products to increase its nutritional value. This is done to ensure that people, especially women who might become pregnant, can meet the recommended daily intake of folate.
Step-by-step explanation:
Pepsin is a digestive enzyme that is secreted in the acidic environment of the stomach, and it works best at a very low pH level. The optimum pH for pepsin to effectively break down proteins is approximately 1.5. This pH level is maintained by the hydrochloric acid (HCl) secreted by glands in the stomach lining, which can bring the pH of gastric juice to about 1.0. However, when food enters the stomach, it may raise the pH to between 1.5 and 2.5, still suitable for pepsin to convert the inactive form pepsinogen into the active enzyme.