I want to make my own fruit flavors for cake and cake fillings but I am not sure what to use. For example I want to make three types raspberry filling: Buttercream, mousse, and a perserve type of thing. What do I use as the fruit flavoring in each of these? Puree, extract, emulsion, coulis, fruit paste?

A few other things I was wondering as well:

1. How do I make fruit puree? Do I need to strain it?
2. If I make apple puree am I making apple sauce? What is the difference?
3. Can you freeze puree, compote, or coulis and if so for how long? Once at room temperature can they be refrozen?
4. To use puree in my recipes do I just substitiute the puree for the liquid (milk/ water)?

Any other ideas would be helpful.