Sour Patch Kids

Sour Patch Kids 14.5 Reactions of Acids 14.9 The pH and pOH Scales ... 

A number of other foods contain acids as well. The taste of lemons and limes, the bite of sourdough bread, and the tang of a tomato are all caused by acids. Acids are substances that— by one definition that we will elaborate on later— produce H ions in solution. When the citric and tartaric acids from a Sour Patch Kid combine with saliva in your mouth, they produce H ions. Those H ions react with protein molecules on your tongue. The protein molecules then change shape, sending an electrical signal to your brain that you experience as a sour taste ( Figure 14.1). 

We have just discussed examples of the sour taste of adds (Sour Patch Kids) and their ability to dissolve metals (spy movies). Acids also turn blue litmus paper red. Litmus paper contains a dye that turns red in addic solutions ( Figure 14.3). In the laboratory, litmus paper is used routinely to test the addity of solutions. Some common acids are listed in Table 14.1. Hydrochloric add is found in most chemistry laboratories. It is used in industry to clean metals, to prepare and process some foods, and to refine metal ores. 

Bases are less common in foods than acids because of their bitter taste. A Sour Patch Kid coated with a base would never sell. Our aversion to the taste of bases is probably an adaptation to protect us against alkaloids, organic bases foimd in plants (see the Chemistry and Health box in Section 14.9). Alkaloids are often poisonous—the active component of hemlock, for example, is the alkaloid coniine—and their bitter taste warns us against eating tirem. Nonetheless, some foods, such as coffee, contain small amounts of base (caffeine is a base). Many people enjoy the bitterness, but only after acquiring the taste over time. 

What makes tart gummy candies, such as Sour Patch Kids, sour ... 

---