The reason we use apples in most juices is because they are sweet but aren't an overpowering flavour. Apples are great for juicing as they don't need peeling, but people often do remove the core. Apples go well with pretty much every other type of fruit and vegetable, and add a great flavour to your juice.
Depending on if you want a bitter or sweeter tasting juice, this is really down to what sort of apples you use. Using Cox or Granny Smith apples will create a bitter, sharper taste. However if you prefer a lighter tasting juice, go for Pink Lady, Golden Delicious or Royal Gala apples.
Apples contain high levels of a soluble fibre called pectin, that is said to bind to toxins, which then causes them to be pushed out of the gut. Apples are also said to contain substances that can block cancer causing actions of different pollutants, for example those gained from smoking cigarettes. These substances are also said to eradicate cholesterol from the body, breaking down excessive amounts in the liver. Pasteurised juices don't contain much of these substances – another reason why you should be juicing apples!
Apples contain plenty of vitamins and minerals – just a few of these include Vitamins A, B, C and E. They also contain Calcium, Magnesium and Potassium, plus others, even some that haven't been recognised yet!