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Chapter 23 Separation Techniques: Mechanical and Chemical Methods
The stomach and intestinal walls release water into food in the
digestive tract. This helps create the liquidity needed for chemical
reactions to occur. These reactions will break down protein,
carbohydrates, and fat. These macromolecules must be broken into
components that are small enough to be absorbed through the intestinal
wall for use by the body.
As the partially digested food solution reaches the small intestine,
the gallbladder releases bile. Bile is an emulsifi er. It suspends the fat
molecules in the partially digested food solution. Bile is produced
in the liver and stored in the gallbladder until needed. In addition
to bile, digestive enzymes from the pancreas are released into the
small intestine to break down the macromolecules. The pancreas
also releases bicarbonate to neutralize the hydrochloric acid from
the stomach. This raises the pH of the small intestine to about 7.
Food residue moves from the small intestine to the large intestine.
Here, water and minerals are removed from digested food. The large
intestine also contains colonies of bacteria that produce vitamin K.
carbohydrates (such as potatoes)
fats ( such as butter)
proteins (such as steak)
monosaccharides
glycerol, monoglycerides,
and free fatty acids
amino acids
Nutrient Breakdown During Digestion
Goodheart-Willcox Publisher
23-10 The body breaks down macronutrients from foods into usable substances through the process of digestion.