The acidic semidigested food coming out of the stomach is neutralized

The acidic semidigested food coming out of the stomach is neutralized by

pancreatic juice
duodenal secretion
large intestine secretion
bile juice
This question was previously asked in
UPSC NDA-2 – 2018
The acidic semidigested food (chyme) coming out of the stomach into the duodenum is neutralized primarily by the bicarbonate ions present in pancreatic juice. Bile juice and duodenal secretions also contribute bicarbonate.
– Stomach contents are highly acidic (pH 1.5-3.5) due to hydrochloric acid.
– Enzymes in the small intestine, particularly pancreatic enzymes, function optimally in a slightly alkaline environment (pH 7-8).
– Pancreatic juice is rich in bicarbonate ions (HCO₃⁻), which effectively neutralize the acidity of the chyme entering the duodenum, raising the pH to the optimal range for enzyme activity.
Bile juice, produced by the liver, is also alkaline (pH 7.6-8.6) due to bicarbonate ions absorbed from the blood and secreted by bile duct cells, and it also helps in neutralization, in addition to its primary role in fat emulsification. Duodenal glands (Brunner’s glands) also secrete alkaline mucus containing bicarbonate, providing protection and lubrication. However, pancreatic juice is generally considered the main source of bicarbonate for bulk neutralization in the duodenum.