Many fruits and vegetables have a high sugar content. Most of these also have a high starch content; starches convert to sugar as the produce ripens, which makes them more flavorful. Although most vegetables are considered savory and are prepared accordingly, some vegetables have a high enough sugar content that they can be used to prepare sweet dishes, such as desserts. And although almost all fruits are sweet by definition, some are sweeter than others and consequently have a higher sugar content.
Native to Europe, parsnips (Pastinaca sativa) have been cultivated there since Roman times. Before cane sugar was readily available, parsnips were often used to sweeten cakes and other desserts. Parsnips look like a large white carrot, and are a member of the same botanical family (Umbelliferae). Parsnips are a starchy vegetable and their flavor improves after they are exposed to freezing temperatures. When this happens, some of the starch is converted to sugar. Parsnips are often left in the ground all winter under a protective mulch. When dug in spring, much of their natural starch has been converted to sugar. Spring-dug parsnips are the sweetest and best tasting.
Sweet potatoes (Ipomoea batatas) are well-known for their high sugar content. Aside from the ever-popular sweet potato pie--a stand-in for pumpkin pie--the high sugar levels in sweet potatoes lend them for use in many sweet dishes. They can add both flavor and sweetness to breads, cakes and cookies in either starring or supporting roles. Cut to resemble either french fries or potato chips, they can be deep fried or baked and coated with a cinnamon sugar mixture for an unusual snack. Sweet potatoes are heat-loving vegetables and are more commonly grow in tropical areas than in temperate zones.
Apples (Malus domestica var.) are one of the most popular of all fruits. All varieties of apples (except crab apples) have a high sugar content, but some varieties contain more sugar than others. These varieties make the best dessert or snack apples for eating out of hand. Because of their high sugar content, they are also frequently used to make wine. For the sweetest apples, try Golden Delicious, Jonathan, Winesap or Stayman.
Pineapples (Ananas cosmosus) are native to South America. The South American varieties are green and the new varieties developed and now grown in Hawaii are yellow. Pineapples contain a lot of sugar and no acid. They must be picked when they are ripe and will not ripen further after picking. To tell if a pineapple is fully ripe, look at the stem end. The skin should have a yellow cast to it, even if it is a green variety. Yellow varieties will show a more intense yellow color at the stem end when fully ripe. Another indication of ripeness is scent. Smell the stem end of a pineapple; if it has a strong pineapple scent, it is ripe.