Golden Apple

Golden Apples are moderately difficult to obtain, but are the most beneficial Food item. They are extremely rarely found in Dungeon, Stronghold, and Abandoned Mine Shaft chests, though they can also be obtained by crafting a Red Apple and eight Gold Nuggets together. Eating one heals, and grants enhanced regeneration for 4 seconds, regardless of hunger level. They are considered to be very valuable to players and are often kept as a kind of trophy, although it is now easier to obtain after 1.1.0. When in your inventory, Golden Apples shine purple, much like enchanted tools and armor.

Advantages

 * They are the only food items that cause temporary constant health regeneration that is not dependent on the player's hunger. This is indicated by the line of hearts bobbing up and down in a wave pattern, with each full wave restoring half a heart.
 * Compared with potions of regeneration, golden apples are available for fighting monsters before you are able to brew or even go to the Nether in single player mode. This is especially true for Blaze, who are the sole source of Blaze Rods needed for brewing.
 * Golden apples also are stackable up to 64 like other food, unlike restoration potions which take up an inventory space with just one.

Disadvantages

 * Apples can come from Dungeons and now can be cut from trees, but they are still hard to find due to the fact that not all Dungeons have apples in the chest and that when you cut down a tree not every tree has an apple.
 * Golden apples have an extremely slim chance of appearing in chests: 1/125 (0.8%).
 * As of the 1.0.0 release health generation is no longer unique to golden apples as the player can brew health regeneration potions. Not only do potions last longer (0:45) than a golden apple (0:04), they can also be upgraded with redstone and glowstone dust to either heal the player more rapidly or to have an even longer duration (2:00). Since golden apples are a food, they cannot be upgraded, unlike potions.

History
Golden Apples were added at some point between late Indev and mid Infdev,(needs clarification) some time after the addition of Red Apples themselves. They healed a full ten hearts of health when eaten prior to the Beta 1.8 update, making them the single best food in the entire game-at the expense of being near unobtainable.

Since Beta 1.8, due to the addition of hunger, Golden Apples were changed so that they only healed five hunger points, but also gave the status effect of regeneration for 30 seconds.

Since Beta 1.9 pre-release 2, Golden Apples gained a purple glow when viewed from the player's inventory, and its name tag was changed from the standard white to a magenta color.

In the second weekly build, 11w48a, Gold Apples became easier to craft. Red apples became able to very rarely drop from Oak Leaves, meaning that players no longer have to venture into Strongholds/Dungeons/Abandoned Mineshafts to find one.

Before 1.0.0, golden apples were the only food item that could completely refill the player's health, without a full hunger bar.

In Minecraft 1.1, Golden Apples were nerfed so that they only healed two hunger and only gave 4 seconds of regeneration. To balance this, their crafting recipe was changed to requiring Gold Nuggets instead of Gold Blocks. For although its natural spawn is rare, it is easier to obtain through crafting. With now common availability of apples and a cost of 1.25% their former cost in gold, they are for the first time a practical source of healing in Survival. All of these factors make the Golden Apple's value decrease greatly.

Trivia

 * The Golden Apple is just a recolor of a Red Apple