Apples

In every grocery store I shop at, apples take up the most real estate in the produce section. All year long, while other fruits come and go, shiny round apples sit waiting to be bought. Why are apples so popular? Besides the great taste and crisp texture, apples are hardy and useful. Read on to learn more.

An apple is a fruit. It grows on an apple tree and is harvested in the late summer or fall. These trees are very hardy and can grow in almost any temperate region. Domesticated, the trees grow to be six to fifteen feet tall. In the wild they can grow up to forty feet tall. Apple seeds do not grow into trees that produce the same apple variety they came from. So, to grow a specific type of apple, commercial apple trees are grafted onto rootstock. Grafting is the process of binding a branch or branches from one tree onto the trunk of another tree.

 

There are thousands of varieties of apples. They can be red, yellow, green or a combination of these colors. The inside flesh is typically off-white. The apple core is at the center of the apple. It is harder than the surrounding flesh and has the seeds.  Apples are round and typically between two and four inches in diameter. One end of the apple dimples in and connects to the stem, the other end has the residue of the apple flower.

Apple Nutrition

Apples are a good source of vitamin C. A medium sized apple (182g, or 3 inch diameter) has approximately 25g of carbohydrates, 19g of sugars, 0.5g of protein, and 4.4g dietary fiber.

Apple History

Historically, apples were gathered from wild apple or crabapple trees. Remains of apples have been found in European Neolithic sites. It is speculated that apples were first domesticated in the Middle East and the method traveled both west and east. The Romans encouraged the spread of domestic apple trees throughout Europe. In the first century A.D. Pliny knew of about thirty apple varieties. By 1640 approximately sixty varieties were listed in John Parkinson’s Theatrum Botanicum . In Downing’s Fruits, printed in 1866, the apple variety count was up to 643. Now there are about five thousand varieties.

Out of the thousands of apple varieties created, only about thirty are used commercially. Those varieties show up in your local grocery stores at different times. Some apples, like Red Delicious, are available year round. Others do not store as well, so they are available seasonally.

Apple Storage

Part of the reason apples have been so popular throughout history is because they store well. Most apple varieties can last for months in a cool cellar. Today, instead of using a cellar apples are stored in refrigerators. Cool temperatures decrease the rate at which the apples produce ethylene gas. Ethylene is a gaseous plant hormone that helps control the aging or ripening process. Less ethylene production means it will take an apple longer to become overripe.

Ethylene production can also be manipulated by controlling the atmosphere. Decreasing the oxygen levels will decrease ethylene production. Increasing carbon dioxide levels will also decrease ethylene production. The air that we breathe contains 21% oxygen and less than 1% carbon dioxide. In comparison, the ideal storage conditions for apples are 2-3% oxygen and 2-5% carbon dioxide. In these conditions ethylene production almost stops and apples ripen very slowly.

Controlling the humidity is also important. Ideally, the humidity is high enough to prevent the apples from loosing water but not so moist that bacteria and fungi grow easily.

Thanks to these manipulations of storage conditions, Gala apples and other less hardy apple varieties are available in stores almost year round.

Apple Uses

Apples are a very versatile fruit. They can be eaten raw, made into juice, cider, applesauce, jelly, and many desserts.

Apple pomace, the leftover plant material from making juice, is a good source of pectin. Pectin is a gelling agent in jellies and jams. It can also be used as a stabilizer and source of dietary fiber.

One unique use for apples is as a substitue for other fruits. Apples hold up well to cooking and storage while many other fruits do not. They have a mild flavor which can be masked and the pale color of apple flesh is easy to add color to. Because of these attributes, apples can easily impersonate other fruits. Just the other day I ate a fruit medley granola bar. The main fruit flavors were cranberry and strawberry. But strawberry  was not in the list of ingredients. The granola bar had tiny strawberry-flavored, red colored pieces of apple in it. What a genius way to create a product with a fruit flavor that would otherwise be impossible or too costly to make!

Wrap Up

Apples are an amazing fruit. They are not the most nutrient dense fruit, but they are still good for you, convenient, and tasty. You can eat them straight off of the tree, store them for later, or make them into many dishes. It is no wonder apples continue to be a favorite.

 

Images: John De Boer, Patrick Hajzler, Jay Simmons, Colin Brough

Sources:

• “Basic Report:  09003, Apples, raw, with skin.” National Nutrient Database for Standard Reference. Release 28. Accessed Jan 11, 2016.
• Fennema’s Food Chemistry, 4^th Edition, edited by Srinivasan Damodaran, Kirk L Parking, and Owen R Fennema. 2008.
• Foods: A Scientific Approach, 3rd Edition, by Helen Charley and Connie Weaver. 1998.
• The New Oxford Book of Food Plants: A Guide to the Fruit, Vegetables, Herbs and Spices of the World. by JG Vaughan and CA Geissler. Illustrated by BE Nicholson. 1997.
• On Food and Cooking: The Science and Lore of the Kitchen by Harold McGee. 2004.
• Postharvest: an Introduction to the Physiology and Handling of Fruit, Vegetables and Ornamentals, 5th Edition by Ron Wills, Barry McGlasson, Doug Graham, and Daryl Joyce. 2007.
• Vegetables, Herbs, and Fruit: An Illustrated Encyclopedia by Matthew Biggs, Jekka McVicar, and Bob Flowerdew. 2006.