Lingual glands secrete lingual lipase into the mouth. Where does this enzyme actually begin working, and on what?

1. Lingual glands in the lamina propria of the tongue secrete a serous fluid containing lingual lipase. 2. The enzyme is therefore released in the mouth, which is what makes this question a trap. 3. Lingual lipase does not begin working until it is activated in the stomach. 4. The trigger is the acidity of chyme, which inactivates salivary amylase and activates lingual lipase. 5. Its substrate is triglycerides, which it breaks into free fatty acids and mono- and diglycerides. 6. So the two options placing its activity in the mouth confuse the site of release with the site of action. 7. The duodenum option is wrong because activation has already happened by the time chyme leaves the stomach. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 23 "The Digestive System", section 23.3 The Mouth, Pharynx, and Esophagus_