In Brazil, "sumo" means the liquid substance of the essence of the fruit. So it could be used for "juice", but it would sound very unusual.
For oranges, we call "sumo" the bitter liquid that comes from the peel. So if you say "sumo de laranja", you can be misunderstood.
By the way, I've noticed that when you ask for 'sumo' in Portuguese cafés, you might easily end up with Fanta and other beverages that are only superficially similar to juice. :/ And to get real juice, you have to ask for 'sumo natural'.
Is it same for 'suco' in Brazil?
Tecnically, it's correct.
But there's no context to identify whose juice is that. So you go to the most probable answer: talking to another person, "você".
If you had in context another person you're talking about, you could say "o suco é seu" reffering to him. But even so, you could be misunderstood.
Using the pflammertsma's option is best. "o suco é dele (de+ele)"
After reading all replies I'm still confused, so I'd like to check if my thinking is correct:
Due to Brazil's usage of "Você" instead of "Tu", the correct way of using possessives for "yours" is to use "Seu/Sua" - but with possessives this becomes confusing because now you don't know if it means "yours" or "hers/his". So the way to come out of this quandary people have decided to use "Seu" only for "your/yours" and to say "hers/his" you use the form of "something of her / of him". So to say "His juice", you transform that to "The juice of him" and that translates to "O suco é de ele". But because this is used so often people just concatenated "de ele" to "dele" and now you have "O suco é dele".
Is that correct?
I am laughing my ass off :D :D Brazilian Portuguese is a comedy :D
Normally, if you use the article "o" (or a/os/as) it is a designation of an individual object. Saying "o seu" would imply that there is another "suco" that is not "seu" - yours. The most neutral translation is "o suco é seu". Imagine that you and a friend asked for a juice on a bar counter. While you were distracted looking aside you try to grab your glass of juice and you don't know witch is yours. You can ask "Este suco é o seu?" - verifying the correct one. But imagine you offer a juice to someone. Than you should say "o suco é seu" - meaning that the property is transferred. On the other hand, when the bar tender comes back to grab the empty glass you could say "Pode levar o meu" - "You can take mine". You should not say "Pode levar meu" - "You can take my" - It's confusing.