The ingredients in Pepsi are carbonated water, high fructose corn syrup, caramel color, sugar and phosphoric acid, as well as caffeine, citric acid and natural flavor, according to PepsiCo Beverages. There are 63 milligrams of caffeine in 20 fluid ounces of Pepsi, 15 milligrams of potassium and 89 milligrams of phosphorus.
A further breakdown of what each of these ingredients actually consists of can be found on WhatIsThatIngredient.com Carbonated water is carbon dioxide gas dissolved in plain water. High fructose corn syrup is a form of sugar made from corn starches in a liquid form. The color comes from burnt or caramelized sugars and starches that are usually suspended in water. The sugar most commonly used in Pepsi is a granular form of processed sugar cane or sugar beet plants.
Pepsi also has caffeine, a central nervous stimulant, which restores alertness and keeps people from being drowsy. Phosphoric acid is also added to give a bitter acid accent similar to lemon; it is calcium phosphate rock treated with sulfuric acid. Citric acid is also added as a flavoring; it is a powder made from the product of fermented carbohydrates.
Natural flavor may be the most ambiguous of the ingredients in Pepsi. It is flavoring in the form of an essence or extractive, protein hydrolysate, distillate, or any product of roasting or heating or enzymolysis from a spice, fruit or fruit juice, vegetable or vegetable juice, edible yeast, herb or similar plant material. Natural flavors are also derived from meat, seafood, poultry, eggs, dairy products, or fermentation products from these different kinds of food.