Can 3D printing change our future dramatically, by generating any material. Eg Human organs, 3D printed any food of our liking etc ?
At present 3d printing reproduces shapes, using various (plastic?) materials. The stuff you are asking about cannot be made with the current technology.
Actually, printing can currently be done using a huge variety of plastics, metals, resins, ceramics, etc. The ones that aren't ungodly expensive or complicated are the plastics As far as food goes however, I seriously doubt printing will be anything more than a novelty. I mean - all it does is render shapes which is already achievable with things like cookie cutters and muffin tins. With the exception of some ornate chocolate sculptures or cake icing, I think it's completely useless for food.
Well 3D printing doesn't create raw materials. It creates goods, and they are being used experimentaly to create organs in labs.