Varieties ~
The most popular variety is the Delicious.  Good apples for juicing are Delicious (both red and golden yellow), Granny Smith, and Winesap varieties.

(There are a great many varieties of apples, the Delicious being the mildest and usually the easiest to digest.  Apples have a cleansing effect which is particularly noticeable when impactions are present in the intestines and in this condition during the cleansing process some varieties are likely to give some discomfort.  When this is the case then it is sometimes found that some other varieties may be eaten with less or no discomfort.)

Key Benefits~
Apples are a good source of many vitamins and minerals, particularly if they are UNpeeled.  Unpeeled apples are particularly high in non-provitamin A carotenes and pectin.  Pectin is a remarkable type of fiber that has been shown to exert a number of beneficial effects.  Because it is a gel-forming fiber, pectin can improve the intestinal muscle's ability to push waste through the gastrointestinal tract. Pectin can also bind to and eliminate toxins in the gut, as well as help reduce cholesterol levels. Since pectin is a water-soluble fiber, fresh juice still retains a portion of this beneficial fiber.  Apple juice has also been shown to be antiviral.

Apples, as well as other soft fruits and vegetables, contain ellagic, chlorogenic, and caffeic acids, anutrients with significant anticancer actions.*  Fresh whole apples and fresh apple juice contain approximately 100-130mg per 100g (roughly 3-1/2 ounces) of these valuable compounds.  The content of these compounds in canned, bottled, or frozen apple juice is at or near zero.  Another strong case for drinking your apple juice fresh.

A great deal of exciting research has been done on ellagic acid, which has been referred to as a "new breed of anticancer drugs."  One of its prime actions is to protect against damage to chromosomes and block the cancer-causing actions of many pollutants.**  Specifically, ellagic acid has been shown to block the cancer-causing effects of several compounds in cigarette smoke known collectively as polycyclic aromatic hydrocarbons (PAH).  Ellagic acid is a potent antioxidant and has also shown an ability to increase many of the body's antioxidant compounds, including glutathione.***  Ellagic acid is just one more example of an anutrient with powerful anticancer properties, and it is one more example of why we need to consume foods fresh.

(Apples, when eaten on an empty stomach, tend to stimulate the activities of the lower intestines. They are rich in magnesium, iron and silicon, while their potassium content is very high.  They contain approximately 85% water and are a valuable aid to digestion, both in their natural state and in the form of fresh juice.)

(The juice of fresh apples, when raw, is of great help in the case of fevers and inflammation.  Apple cider has a beneficial effect on the system.  No sugar of any kind should ever be added to apples.  If sweetening is needed, then honey should be used.)

Selection~
You should definitely buy organic apples if you can.  Apples will often be waxed to keep them fresher longer.  Be aware that even organic apples will appear "waxy," because apples have a natural coating of a waxlike substance.

Fresh apples should be firm, crisp, and well-colored.  If an apple lacks color, it has likely been picked before it was fully mature and has been ripened artificially.  Apples picked when mature will have more color and better flavor, and will store longer than apples picked too early.  Check out the hardness of the apple.  A fresh apple will produce a characteristic snap when you apply pressure to the skin with a finger.  Overripe apples will not give you a crisp snap; they will feel softer.

It is obvious fresh apple juice has benefits of its own, but one of the key uses of apples is to mix it with other fruits as well as vegetables because of its sweet but not overpowering flavor.

References~
   *Kuhnau J, The flavonoids:  A class of semi-essential food components:  Their role
    in human nutrition, Wld Rev Nutr Diet 24:117-91, 1976.
 **Smart RC, Huang MT, Change RL et al., Effect of ellagic acid and 3-O-decylellagic
    acid on the formation of benzo[a]-pyrene in mice, Carcinogenesis 7:1669-75, 1986.
***Majid S, Khanduja KL, Gandhi RK et al., Influence of ellagic acid on antioxidant
    defense system and lipid peroxidation in mice, Biochem Pharmacol 42:1441-45,
    1991.

Thanks to~
(The Vegetarian Guide to Diet & Salad)
by Dr. N.W. Walker, D.Sc., pp. 102-103.

The Complete Book of Juicing: Your Delicious Guide to Youthful Vitality
by Michael T. Murray, N.D., Jay Kordich, pp. 71-73.