Spinach Powder Substances that are added to food to maintain or improve the safety, freshness, taste, texture, or appearance of food are known as food additives. Food additives have been used for centuries to enhance the appearance and flavor of food and prolong shelf life. Food additives can be derived from plants, animals, or minerals, or they can be synthetic. Functional substance that is normally neither consumed as a food itself nor is used as a food ingredient, but is intentionally added to food (usually in small quantities) to assist in its processing or to improve its certain characteristics such as aroma, color, consistency, taste, texture, packaging, and/or shelf life.