None at all. They argue that "the fruit of the vine" (Matt. 26:29) is to be understood as grape juice, but there are three main problems with that notion.
First, the two common drinks in Palestine were water and wine. The phrase "fruit of the vine" meant "product of the vine." Grape vines were grown not for grapes, but for wine.
Second, grape juice spoils quickly without refrigeration. There were very few refrigerators in Palestine at the time of Christ.
Third, at the wedding in Cana, after Christ changed water to wine, the headwaiter who tasted it said to the bridegroom, "Everyone serves good wine first, and then when people have drunk freely, an inferior one; but you have kept the good wine until now" (Jn 2:10).
Translation: Normally a host will put the good wine out first so, when people get tipsy (which you can't do with grape juice), they won't notice the cheap stuff later on. You, on the other hand, have saved the good stuff for last.