Sixteenth-century author William Butler wrote this tribute to the strawberry: "Doubtless God could have made a better berry, but doubtless God never did." Red, juicy and conically shaped, the strawberry is a member of the rose family and has grown wild for centuries in both the Americas and Europe. The Romans valued the fruit for its reputed therapeutic powers for everything from loose teeth to gastritis. However, it wasn't until the late 13th century that the plant was first cultivated. The most common American variety is the result of several centuries of crossbreeding of the wild Virginia strawberry (North America's main native strawberry) and a Chilean variety.Commercial strawberry products include preserves, jams, jellies, syrups and various desserts. Strawberries are an excellent source of vitamin C and also provide some potassium and iron Stabilizers, thickeners and gelling agents, like agar or pectin (used in jam for example) give foods a firmer texture. While they are not true emulsifiers, they help to stabilize emulsions. Food additives are substances added to food to preserve flavour or improve its taste and appearance. Some additives have been used for centuries; for example, preserving food by pickling (with vinegar), salting, as with bacon, preserving sweets or using sulfur dioxide as in some wines. With the advent of processed foods in the second half of the 20th century, many more additives have been introduced, of both natural and artificial origin.