Final answer:
A substance that enhances food's taste, texture, or appearance is called a food additive, which is regulated by the FDA for safety and effectiveness.
Step-by-step explanation:
A substance added to food to improve its taste, texture, or appearance is called a food additive. These additives provide a variety of beneficial functions, such as enhancing flavors, maintaining or improving the appearance with color additives, and giving foods the desired consistency and texture through emulsifiers, stabilizers, and thickeners. The Food and Drug Administration (FDA) regulates all color additives and other food ingredients to ensure safety, efficacy, and accurate labeling for consumption.