There are a few fruits and vegetables that simply can’t be forced into giving up their precious liquids. A juicing machine or juice extractor removes the juice or liquid from fruits or vegetables by force. And because the machine is doing the squeezing and separating of the pulp and juice, you can juice many hard fruits and vegetables that you couldn’t juice by hand.
The fruits and vegetables that you can't juice can be used in smoothies:
Avocado: Avocado is a great source of omega-3 fatty acids and, when ripe, it blends nicely, making smoothies and dips creamy and smooth. But if you try to juice it, it will only jam your juice machine. You can add avocado to fresh juice, though — here’s how: In a blender, combine 1 cup fresh juice with 1/2 avocado, cut into chunks. Blend until smooth. Pour this mixture into the rest of your juice and mix well. The avocado will make the juice thick and creamy.
Banana: Bananas are high in potassium, but they gum up the working parts of the juicer when you try to juice them. To add bananas to your glass of fresh juice, follow these steps: In a blender, combine 1 cup fresh juice with 1/2 banana, cut into chunks. Blend until smooth. Pour this mixture into the rest of your juice and mix well.
Rhubarb: Rhubarb leaves are high in oxalic acid and inedible, but the stalks contain such tiny amounts of the toxic acid that most people can eat small amounts of rhubarb stalks in pie and jam without experiencing problems. However, because of the amount of fresh rhubarb required to make one glass of juice, the amount of nutrients and the toxic oxalic acid is concentrated and much higher than if you eat the stalks raw. Juicing rhubarb could cause a reaction of stomach irritation and kidney problems, so you’re better off leaving it for smoothies and rhubarb pie.
Winter squash: Winter squash is just too hard to juice. In fact, you can damage your grating basket or blades if you try to juice raw squash. But the nutrients are exceptional, so to juice squash, you can soften chunks of butternut or acorn squash by lightly steaming them before juicing.
Nuts, seeds, and grains: Nuts, seeds, and grains aren’t suitable for juicing, but you can finely chop them and add them to fresh juice as a protein boost.
