Are apples beneficial to compost?

First are apples "good" to compost and do they really add anything to the soil?

Second, do they tend to take longer to break down and why do they smell like vinegar?
Thanks, John.

Buried in a big enough pile of brown (leaves are good) they are fine. Watch for scavenging animals, however. I had a trash barrel full of rotten apples to compost once; a favor for a friend. They turned into goo quikly, stunk for a day or two, but after they were a liquid, they "melted" into the compost, added some good green material, and promptly disappeared. Having dry carbon-rich material as a foil is key.

The vineagar smell is from the fact that there are a lot of wet sugars to break down initially, and the bacteria that does that is the same as in vineagar. (When humanity found out about starving this process of oxygen, the results were much more likable. Can you say:
applejack!)
Kenton