Well, I'd dissolve the yeast in some of the juice diluted with water and a pinch of yeast nutrient. That should be good. Maybe 1/2 juice and 1/2 water (a cup or so of each) would be enough to get it going well.
__________________ Broken Leg Brewery Giving beer a leg to stand on since 2006
An easy technique that I learned from a fellow brewer is to buy some of those cheap six packs of 10 oz bottles of apple juice from Walmart and when you need a starter, just open one, pour about 1/2 of it out, shake it up to aerate it, add your yeast to it and replace the cap or even better use an airlock. Check it frequently as the last one I did came alive and had about 1.5 inches of foam on top in only 3 hours.