Many criteria affect how a flavour performs in the application they are used in. The majority of flavours work in most application but their profile will change depending on the applications and the ingredients used to make up the product, also processing techniques can alter the profile. The main points are listed below to aid selection:
If a flavour is to be exposed to heat either by baking or pasteurization process the flavour must be a heat/bake stable. This means that the alcoholic content of the flavour should be below 30% to avoid the flavour being cooked out.
This is important for drink application. Some oil based flavours will not be suitable as they will not emulsify with liquids.
The presence of fat in a product can reduce the impact of a flavour profile, high fat products (usually above approx 25%) will need higher dosage levels or more concentrated flavours. Applications high fat yoghurts.
Generally if a product has a high sugar content (cane sugar, sucrose, fructose) this will aid the flavor profile, as most flavours work well in a sugar sweetened application. This is untrue if the product is artificially sweetened (acelsufame K, Aspartame etc,etc) as they tend to change the profile through the products shelf life and also have a bitter and metallic aftertaste. Some flavours can be used to try and mask this bitterness, tests usually need to be done in a laboratory environment to monitor the product over its shelf life.
Powders can be used in most application, but in areas such as dairy etc., they tend to contribute to a powdery mouthfeel, which is not always desirable. They can be used in baking and some pharmaceutical applications and also dry products such as milk shake powders, coatings, etc.
Limited dosage and restricted ingredients in some countries may influence the choice and creation of some flavours.
Some flavours will not be suitable for religious dietary needs, i.e. Muslim or Jewish diets. If a specific need is required check that the flavour is suitable, usually it can be reformulated.