Squeezed from fresh oranges.
Juice can be obtained from the mission: Meet and Greet with Django or collect the gift box from the event: Day of the Bright Sun and maybe (This detail is written in the game.) purchased at the Food Store.
Data taken from game assets, game version 7.0100427. Listed values are without The Giver skill, which gives an extra 1-2 points.
All other characters will default to Neutral (+1).