A food may test positive for glucose but not have enough glucose to taste sweet, or the sweet flavor may be masked, . by a sour flavor. Sweet foods may have little glucose, but significant amounts of other sugars (or artificial sweeteners that bind to taste receptors for sugars). When there is a small amount of a type of molecule (. fat in pretzels) the tests used in this activity may not be sensitive enough to read positive. The results of the protein test for pretzels may be somewhat ambiguous, but if a little bit of pretzel is crushed.
