What causes apples to turn grey/brown?!


Question: What causes apples to turn grey/brown!?
When I slice an apple, ang leave it for 5 mins, it has grey/brown spots!. :\ not much of a presentation for cooking!.Www@FoodAQ@Com


Answers:
Apples contain phenolic compounds and enzymes that discolor on contact with oxygen!. Slicing through an apple, breaks the cell membrane, allowing oxygen to come in contact!.

Apples also contain tannins!. Tannins are astringent, a bitter plant polyphenol that either bind, shrink and precipitate proteins!. Tannins darken when exposed to metal or hard water!. Let's say you are slicing the apple with a knife, or you rinse off the sliced apple with tap water!. Tap water contains small amounts of metal!.Www@FoodAQ@Com

It is a chemical reaction to oxygen exposure, same happens to artichokes, quinces, avocados etc!. Simply sprinkle the cut and exposed areas with a little lemon juice or sugar - depending on what you are cooking and they should stay fine!.Www@FoodAQ@Com

it's a chemical reaction to do with exposure to oxygen!. rub a little water with some lemon juice on the apple and it won't happen!. the acid in the lemon juice inhibits the reaction!.Www@FoodAQ@Com

it's an oxidizing tyrosinase reaction forming melanin, the identical pigment in our skin

you can either prevent exposure to oxygen or use a reducing agent like any acid to prevent the reactionWww@FoodAQ@Com

oxygen

either put lemon juice on it,
or dont cut it right awayWww@FoodAQ@Com

the air gets on it , put them in water until you cook themWww@FoodAQ@Com





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