I'd suggest Fruit Fresh - which is a mixture of ascorbic acid and citric acid. It actually takes a lot more lemon juice to do what a tiny amount of powdered citric or ascorbic acid can do. This important when you dehydrate produce since the acidic ingredient will also help prevent bacteria growth, and not just prevent browning (oxidizing) as an antioxidant.

-Grainlady

Will they stay nice looking for several hours?

I like tossing them in pineapple juice, I find the fruit fresh leaves a bit of a acidic taste to it. They last at least four hours (that's as long as I've left them)

It also depends on the type of apple, how long it's been in storage in your refrigerator, have they been banged and bruised between the post-harvest storage, transport to the store, the produce person and general public hands-on treatment - as well as the type of acid you are using as an antioxidant. There are too many variables to give a "guarantee". I have some Fuji apples that are turning brown by the time I get the apple cored and sliced. The Granny Smith apples seem to be better "keepers" than the Fuji or Galas I've been using lately. You may want to do your own testing on the variety/s of apples you want to use, as well as using the different types of acidic ingredients. Give us a report back what works best for you.

-Grainlady

I have a recipe for a fruit dip using apples, and the recipe calls for dipping the apple slices in orange juice. For the dip recipe, this works really well and tastes quite good. I usually use a green organic Granny Smith and a red apple (whatever looks good in the organic section). I usually take the apple slices out of the OJ and put them in a ziplock bag until I 'm ready to plate the dip. I've had good luck with this.

I have a recipe for a fruit dip using apples, and the recipe calls for dipping the apple slices in orange juice. For the dip recipe, this works really well and tastes quite good. I usually use a green organic Granny Smith and a red apple (whatever looks good in the organic section). I usually take the apple slices out of the OJ and put them in a ziplock bag until I 'm ready to plate the dip. I've had good luck with this.

My favorite is fresh lime juice on apples. It works very well and tastes unbelievably good.

I use plain old salt water. Either for serving fresh or freezing. Works great.

I've heard 7-Up recommended before. Paul Prudhomme says that for apples he puts in coleslaw, he always gives them a soak in vinegar/water.

If I need to make an apple dip sort of thing....I just prepare a bowl of ice water and squeeze half a lemon into it....dunk the apples or pears....and remove. No mussing with citric acid, no 7 UP, no worry about what kind of apples and how long they have been stored.(If they have been stored for more than a couple of months you shouldn't be serving them as a feature! they are over the hill)
Now if I were making dried apple rings or drying a lot for long storage....it might be different.
If you are just doing a fruit tray....just dunk in lemon water....they will be un browned for easily 5 to 6 hours.

Thanks for all the responses. I had to make a decision fast and after the first couple of responses I was afraid to do the apple wedges. I was taking a meal to the funeral home for the family to be able to take turns eating during a 7 hr visitation. I decided to just take whole apples, bananas and grapes in a bowl. I will try these suggestions when the fruit doesn't have to sit out for so long. Thanks.

Cortland apples go brown more slowly than other varieties when cut.

Jim