When eating a slice of watermelon, the part usually thrown away is the whitish green at the outside of the fruit, known as the rind. Most people don't do much with the rind, even though watermelon rinds have many uses and can be pickled, added to food dishes, or studied for medicinal benefits.

Watermelon rinds contain citrulline, an amino acid that, in the human body, removes nitrogen from the blood and helps convert it to urine. Citrulline assists in creating arginine, a second amino acid that some people are deficient in. Scientists have studied citrulline and arginine to find out if a treatment can be created for sickle-cell anemia-related afflictions. It might be possible to make a dietary supplement with watermelon rind.

Preserved watermelon rinds are unique and can be more easily prepared than pickles. It can also be a surprise gift to friends. Trim the green skin and pink flesh from the rind. Cut the rind into 1-inch pieces. Dissolve 3 tablespoons of slaked lime in 2 quarts of water and pour this over 4 quarts of rind so that all the pieces are covered. Let them stand up to four hours. To pickle them, use this recipe: 2 tbsp whole cloves, 3 sticks cinnamon, 2 pieces ginger root, 1 thinly-sliced lemon, 8 cups sugar, 1 quart white vinegar and 1 quart water.

Soak 1 cup rice in warm water for two hours and drain water. Grind 1/2 cup coconut, rice, 3 dried red chillies, 1/2 tbsp coriander seeds, 1 tsp cumin seeds, salt to taste and three cups of chopped watermelon rinds without water. To this, add a chopped green onion, two green chilis, 2 tbsp coriander and a few chopped curry leaves to the mixture and mix well. Set it aside for 15 minutes so the flavors combine. Heat a frying pan, add a drop of oil and ladle batter onto it. Spread it into a circle with the back of the ladle. Cook both sides on medium-low until the pancake is golden brown. Serve hot with chutney or honey.

Make a traditional southern relish. Pare off the green skin of the rind with a vegetable peeler. Cut the rind into 1 1/2-inch cubes until you have about 4 cups. Place the rind and 3 tbsp kosher salt in a large plastic bag. Seal and refrigerate the rinds for 24 hours. Remove the rinds from the bag, rinse under cold water and drain. Boil the rinds in a large saucepan with enough water to cover the rinds. Cover the rinds and simmer for 15 minutes. Drain and rinse again. Set the rinds aside. Combine in the saucepan, 1 1/2 cups sugar, 1/2 cup white vinegar, 1/2 cup cider vinegar, 1 tsp pickling spice and a 1-inch piece peeled fresh ginger. Bring this to a boil and stir. Pour the sugar mixture over the rinds, let it stand for a couple hours, then refrigerate for five days.