If you are purchasing a pre-cut watermelon that has already been
sliced into halves or quarters, choose the flesh that is deepest in
color and lacks any white streaking. If the watermelon is seeded, the
seeds should also be deep in color, or white.
When purchasing a whole, uncut watermelon, there are several
features to you'll want to evaluate. The first is its weight. A fully
ripened watermelon will feel heavy for its size. Heaviness in a
watermelon is a good thing because the water content of a watermelon
will typically increase along with ripening, and a fully ripened
watermelon will be over 90% water in terms of weight, and water is one
of the heaviest components in any food
Second, look for a watermelon with a relatively smooth rind that is
slightly dulled on top. The top and the bottom of a watermelon are worth
determining and examining on a watermelon. The bottom or "underbelly"
of a watermelon is the spot where it was resting on the ground. If that
"ground spot" is white or green, the watermelon is unlikely to be fully
ripe. A fully ripened watermelon will often have a ground spot that has
turned creamy yellow in color. Opposite from the ground spot will be the
top of the watermelon. In a fully ripened watermelon, that spot will
typically not be shiny but somewhat dulled. The green color may appear
in many different shades, however, from light green to deeper shades.
Perhaps most controversial about ripeness testing of a watermelon is
whether or not to give it a thump. We've read many arguments both pro
and con. However, among experts who recommend thumping, most seem to
agree that a fully ripened watermelon will have a deeper, hollower
"bass" sound rather than a solid and shallow "soprano" sound.
Finally, some grocers will be willing to core an uncut watermelon
so that you can have an actual taste. (If you decide not to purchase
the melon, the grocer can slice it up and sell it in sliced form.) So
consider requesting this if you are uncertain as to the quality.
Uncut watermelons are best stored at temperatures of 50-60°F (10–16°C).
In many regions, room temperatures will typically be warmer than 60°F
and may be less than ideal for whole watermelon storage due to increased
risk of decay. Better storage temperatures will typically be found in
cellars or basements that are partly or completely below ground level.
While we've seen one study showing increases in lycopene content when
whole watermelon was stored at a temperature of 68°F (20°C), we believe
that a fully-ripe or close-to-fully-ripe melon will already have
outstanding lycopene content and that it would be better for you to err
on the safe side in terms of decay risk if you are planning to wait
several days before slicing open your watermelon.
Like temperatures above 60°F (16°C), temperatures much below 50°F
(10°C) are not recommended for storage of uncut watermelons. This is due
to increased risk of chilling-type injury that can decrease shelf life
and flavor. (Therefore, the refrigerator would not be a good place for
you to store a whole, uncut watermelon for this reason.)
With uncut, whole watermelon, one final storage precaution would
be the avoidance of contact with high ethylene-producing foods like
passion fruit, apples, peaches, pears, and papaya. Watermelons are
ethylene-sensitive fruits that may become overly ripe too quickly under
these circumstances.
Once cut, watermelons should be refrigerated in order to best
preserve their freshness, taste, and juiciness. Store your cut
watermelon in a sealed, hard plastic or glass container with a lid.
By Source : http://www.whfoods.com/
By Source : http://www.whfoods.com/