Prebiotics are compounds in food that induce the growth or activity of beneficial microorganisms such as bacteria and fungi. The most common example is in the gastrointestinal tract, where prebiotics can alter the composition of organisms in the gut microbiome. Dietary prebiotics are typically nondigestible fiber compounds that pass undigested through the upper part of the gastrointestinal tract and stimulate the growth or activity of advantageous bacteria in the colon by acting as substrates for them. They were first identified and named by Marcel Roberfroid in 1995. Depending on the jurisdiction, they may have regulatory scrutiny as food additives for the health claims made for marketing purposes. Common prebiotics used in food manufacturing include beta-glucan from oats, resistant starch from grains and beans, and inulin from chicory root. Definition The definition of prebiotics and the food ingredients that can fall under this classification, has evolved since its first definition in 1995. In its earliest definition, the term prebiotics was used to refer to non-digestible food ingredients that were beneficial to the host through their selective stimulation of specific bacteria within the colon. Further research has suggested that selective stimulation has not been scientifically demonstrated. As a result of research suggesting that prebiotics could impact microorganisms outside of the colon, in 2016 the International Scientific Association for Probiotics and Prebiotics (ISAPP) produced the following definition of prebiotics: a substrate that is selectively used by a host microorganism to produce a health benefit. In 2021, The Global Prebiotic Association (GPA) defined a prebiotic as a product or ingredient that is utilized in the microbiota producing a health or performance benefit. Compounds that can be classified as prebiotics must also meet the following criteria: non-digestible and resistant to breakdown by stomach acid and enzymes in the human gastrointestinal tract fermented by microorganisms on or in the body stimulating the growth and activity of beneficial bacteria Thus, consumption of prebiotics may facilitate the health of the host. Based on the previous classifications, plant-derived carbohydrate compounds called oligosaccharides as well as resistant starch are the main source of prebiotics that have been identified. Specifically, fructans and galactans are two oligosaccharide sources which have been found to stimulate the activity and growth of beneficial bacterial colonies in the gut. Fructans are a category of carbohydrate consisting of fructooligosaccharides (FOS) and inulins, while galactans consist of galactooligosaccharides. Resistant starch has been shown to shift the intestinal bacteria,