why add sucrose to homogenate?

Answer 1

Likely it's to stabilize the structure of one or more organelles or even of cells, depending on what you're homogenizing and how much the homogenizer will agitate the mixture. If there's a higher osmotic pressure inside the organelle or cell than outside, it might take on water until it explodes. Adding sucrose to the homogenizing fluid will make the osmotic pressure outside higher, so the structure will remain intact.

Answer 2

Homogenate of what? I add sucrose to my homogenate of brewed coffee and creamer to make it palatable. Need more info to answer your question.