Final answer:
Making the sauce or dressing with egg or mustard simulates the action of bile salts that emulsify fats, aiding in their breakdown during digestion.
Step-by-step explanation:
Making the sauce or dressing with egg or mustard simulates bile salts. In the small intestine, bile salts emulsify fats, breaking them down into smaller droplets, which increases the available surface area for digestive enzymes such as pancreatic lipase. This process is critical for efficient digestion and absorption of lipids.
Emulsification is important because it transforms large globules of lipid into an emulsion, allowing lipases to more effectively break down triglycerides into fatty acids and glycerides. These components can then be absorbed by epithelial cells in the intestinal lining. Emulsifying agents such as egg yolk, which contains lecithin, and mustard work similarly to bile salts in this regard. Both contain compounds that can act as emulsifiers in sauces and dressings, similar to how bile salts function in lipid digestion.