Flavors are expected to provide a characteristic flavor, as well as cover undesirable base notes. Flavor companies take a multi-functional approach to solving these flavor challenges by using masking agents in combination with flavoring ingredients. Flavors that provide physical and/or chemical properties are the next generation of flavor compounds.
Masking bitterness is perhaps the number one candidate for taste modifiers. Many ingredients cause bitter notes to develop, including artificial sweeteners, botanicals, preservatives, caffeine, glycerin, and grapefruit juice/extract. Bitterness is caused by naturally occurring bitter compounds, or through chemical reactions during storage or processing. Adding sugar helps, but may not be an option, particularly for diet products.