ABSTRACT
This chapter begins with the exploration by setting the scene in “parietal” or “oxyntic” cells. These line the inner walls of the stomach. Oxyntic means acid-generating; parietal comes from the Latin word for “wall. The cells secrete hydrochloric acid at about pH 0.8, giving hydrogen ion concentrations about three million times greater than that found in blood. In making Champagne, the fermentation process converting grape sugars into alcohol and carbon dioxide traps the gas inside the bottle during its second fermentation stage. Champagnes, sparkling wines, and beer are saturated with carbon dioxide produced by the fermentation of sugar. Soda drinks are carbonated commercially. The use of yeast, microbes, and a type of fungus metabolize carbohydrates such as sugars and starches into carbon dioxide and alcohol. The carbon dioxide is supplied either as dry ice or as the liquid.
