Devise a brief experimental protocol (conceptual) to test the hypothesis that increasing mechanical breakdown (chewing) increases the rate of starch digestion in the mouth. Which control and measured outcome would best test the hypothesis?

• A. Have subjects chew identical starchy bread either 5 chews or 50 chews, collect mouth rinse at fixed intervals to assay maltose concentration produced by salivary amylase—control the amount of food and swallowing time; outcome: greater early maltose levels with more chewing supports hypothesis
• B. Feed subjects different breads of varying fat content and measure gastric pH over 24 hours without controlling chewing; infer increased starch digestion from lower pH in the group that chewed more
• C. Give subjects amylase pills and compare blood triglyceride levels after a high-protein meal to conclude chewing’s effect on starch digestion indirectly
• D. Measure breath hydrogen after feeding a fatty meal with different chewing patterns; if breath hydrogen is lower with more chewing, conclude that starch digestion increased

Answer: (A)