I have been trying to introduce fruit and freshly squeezed juice into my diet too. However, since this is something I'm re-introducing to my diet I have been trying to make the foods as easily digestible as possible.
For example, I pour certain juices through a sieve to remove the residue. Also, the sugar concentration can be a bit high in fresh juices so I've been diluting it with an equal amount of water. I'm also eating fruit such as apples and pears without the skin/peel and making sure the fruit isn't too hard and has ripened well. I read somewhere that citrus juices though acidic, leave an alkaline residue in the body - so they should be fine; however, a lot of people with UC can't tolerate citrus fruits so I'm staying away from them for now.
So far I've had no problem with the juice and fruit. In fact, I feel a lot better having a couple of glasses of fresh juice first thing in the morning instead of a solid meal. (The juice combo I've been having is a mixture of red apple, white grapes, pomegranate - and occasionally I add in some carrot juice).