Angiosperm Fruits as Human Food

The Role of Tomatoes, Apples, and Oranges in Agriculture

Sep 1, 2009

"Botanically speaking, tomatoes are the fruit of a vine, just as are cucumbers, squashes, beans, and peas." (Horace Gray)

Botanically speaking, a fruit is an enlarged reproductive structure that forms a seed or multiple seeds on the inside. However, in agriculture, many fruits are referred to as vegetables. In this article a fruit is considered to be any plant part that has seeds inside it. Vegetables would be any plant part without seeds inside – roots, stems, or leaves – that is eaten by humans for food.

Botanists recognize two basic categories of fruits: dry (peanut and walnut) and fleshy (apple and peach). With fleshy fruits it is usually the fruit that is eaten and the seed(s) or core of the fruit discarded. In dry fruits the opposite is true.

The familiar fleshy fruits in this country are the tomato, grape, blueberry, orange, lemon, lime, pumpkin, cantaloupe, watermelon, cucumber, cherry, peach, plum, apple, apricot, and pear.

Agriculturally, the “Big Three” fleshy fruits are the tomato, the apple, and the orange.

The Tomato: Food or Poison?

Tomatoes are native to South America but are believed to have first been domesticated in Mexico. The Spanish conquistadors introduced the tomato to Europe, where it was known as the “Apple of Peru.” The common name comes from the Mexican Indian word for it, tomatl.

Somehow the tomato developed a reputation as being poison (possibly because it is a member of the deadly nightshade family). On top of that, it was also blamed in various circles for everything from emphysema to polio to insanity.

One strange demonstration of its lack of toxicity took place in 1820 in Salem, New Jersey when Colonel Robert Gibbon ate a bushel of tomatoes in front of a crowd gathered they thought to watch his certain death. Not long after, the tomato was reintroduced in this country as a food crop.

And what a food it has become. Yearly in the United States each person consumes approximately 80 pounds of tomatoes sliced, in chunks, or processed into ketchup, salsa, soups, and sauces.

Although they contain only moderate amounts of vitamin A and C, tomatoes lead all other fruits and vegetables in supplying these dietary requirements because of the volume consumed. Plus, a five-ounce tomato has only 35 calories.

There are over 1,000 established varieties in the United States alone including the traditional red varieties but also yellow, pink, and white tomatoes – even striped varieties!

The Apple: Overwhelming Fruit of Choice

Apples were among the first tree fruits domesticated by humans in temperate climes. Most of today’s cultivated varieties are descendants of apples native to the Caucasus Mountains of western Asia where the apple has been in domestication for thousands of years.

A ripe apple is mainly water but also contains about 12% sugar, 1% fiber, and negligible amounts of fat and protein. Approximately 50% of the apples harvested yearly are consumed as fresh fruit, with the remainder processed into applesauce, apple butter, apple cider, apple juice, cider vinegar, dried apples, and canned apples.

Although there are thousands of varieties of apples, only a few can be found in the modern supermarket. Virtually gone from this venue are the old staples such as Baldwin, Early Harvest, Fall Pippin, and Gravenstein. Today, Red Delicious (first discovered in Iowa in the 1870s), Golden Delicious (which arose by chance on a West Virginia farm in 1910), and the tart green Granny Smith (which originated in New Zealand) dominate the shelves. A red and yellow apple also from New Zealand known as Gala is also rising in popularity.

The Orange: A Celebration of Citrus

The citrus family is the source of many edible fleshy fruits: sweet and sour oranges, grapefruits, tangerines, lemons, limes, citrons, pummelos, etrogs, bergamots, and kumquats. Most of these are native to southeastern Asia, where they were undoubtedly cultivated by native peoples.

The New World was introduced to citrus by the Spanish and Portuguese explorers and sour orange trees were growing in Florida as early as 1565. The wild groves of sour oranges became rootstock for the sweet orange industry that began to flourish about the time Florida became a state in 1821. Florida became, and remains, the leading orange-producing state.

Oddly enough, the color development in oranges is not related to ripening. The orange color associated with the fruit develops only under cool nighttime temperatures; in tropical climates the fruits stay green.

However, the public demands an orange-colored orange so growers use various methods to achieve the desired color. The most widely used method involves exposing the ripened fruit to ethylene gas, which promotes the loss of green chlorophyll, thereby making the orange carotene pigments visible.

As a group, the citrus fruits are high in vitamin C and those that are orange-colored also provide some beta-carotene (a precursor to vitamin A) and calcium.

Because of their sweetness, visual appeal, and versatility, fruits may well be the most popular part of angiosperm plants eaten by humans.

Source material gathered by author for presentation in high school and college botany course lectures and for print publication.

The copyright of the article Angiosperm Fruits as Human Food in Ethnobotany is owned by Dennis Holley. Permission to republish Angiosperm Fruits as Human Food in print or online must be granted by the author in writing.