Ola olowo

I really appreciate your work I am an Engr am into machine production here in Nigeria, my question is that is it under most that extruder must have heating devices?I read one of your writeup, can you explain what is the meaning of the following:1) Land height of a die, short land and longer land of a die2) Dextrin. molecules 3) Gelatonizable proteinNote: I need a professional explanation, sir.