In simple recipes the ingredients are responsible for the flavour and nutritional attributes of the food, but in processed foods, much more is expected and required: shelf-life extension, product sterility, colours and flavours as close to fresh as possible, etc. Processed foods for specific markets may be required to have fat, sugar, or salt substitutes but still have the flavour and texture attributes of the original products. In this chapter the basic properties and applications of the main groups of ingredients used in the preparation of canned and other processed foods are discussed.