There are two main anthocyanins that are responsible for the color of strawberries, namely, pelargonin (pelargonidin-3-glucoside) and cyanin (cyanidin-3-monoglucoside). Pelargonin accounts for a minimum of nearly two-thirds of a strawberry's anthocyanin pigments ( http://sciencelinks.jp/j-east/article/200216/000020021602A0562491.php )
Interestingly, anthocyanins are not always red. In fact, they can be purple (e.g. concord grapes), or even blue (e.g. blueberries). Beyond fruits, they are also responsible for most of these same colors in flower petals, tree leaves and other plant parts ("anthocyanin" comes from two Greek words which mean "blue flower").
The differences in color are caused by differences in the pH (that is, the acidity/alkalinity) of the plant tissues. Since strawberries are somewhat acidic, their anthocyanins reflect red light (the acid in strawberries gives them their sourness), whereas the more alkaline fruit of blueberries causes their anthocyanins to reflect blue light (the alkalinity of a blueberry's skin is what makes it slightly bitter tasting). These effects of pH on anthocyanins are also what cause the color changes in litmus paper during a chemical "litmus test".
Much research has been conducted in regards to the antioxidant properties of anthocyanins. In vitro (that is, under laboratory conditions outside of the body), anthocyanins are very powerful absorbers of the single, ionized oxygen atoms commonly referred to as "free radicals". It is therefore speculated that these same anthocyanins may have similarly strong antioxidant capabilities in vivo (that is, inside the body).
If so, eating brightly-colored foods might be very helpful in preventing many chronic illnesses caused by free radical damage, particularly cancer. This is in some doubt, however, due to the fact that only a small fraction of the anthocyanins that people eat is ever absorbed into the bloodstream, and even that amount tends to be eliminated fairly quickly by the body (perhaps too quickly to be effective).
It should also be noted that a link seems to exist between strawberry allergies, strawberry flavor, and a strawberry's red color. For more about this, go to
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