How do I disable antialiasing completely in Zengl?

I'm making a retro-styled 8-bit-like game which I would like to look pixellated when sprites are enlarged, but it seems that the engine is rendering some antialiasing or interpolation when I resize sprites.

I want the sprites resized with no interpolation nor antialiasing whatsoever.
I looked at the source and couldn't figure it out.

Thanks in advance for any indications you can give me.