Some fruit juices can handle pasteurization without hurting flavor and nutrition. Remember, taste is a very good indicator of the quality of the nutrients in the juice. You can get 24 hours out of cantaloupe juice before it loses its fresh flavor, unless juicing a very ripe one, which then needs to be consumed that day. Conversely, citrus juice can taste great, and remain fresh for three days after juicing. I know that adding lemon to my veggie juice not only provides a lift to the heavy veggie flavor, but also helps the juice from oxidizing into an unpleasant muddy color.
Of all store-bought juices I think orange and grapefruit juice tastes the closest to freshly made juices, provided you spend a little more for a quality brand. Two superior brands I love are Simply Orange and Tropicana. If you are looking for a quality juice, watch for “not from concentrate.” The juice will still be pasteurized, but if you buy “not from concentrate” you reduce the processing dramatically. Think about it, why would a company concentrate (remove the water) then re-concentrate? It’s not for the benefit of the consumer; it’s for easier storage, which is for the benefit of the company and their own bottom line. Again, it’s worth spending a little more for quality.
A trick I use to get a great yield of juice that tastes like freshly made is to juice grapefruit and mix it half and half with a quality store-bought orange juice. I don’t know why this is, but it’s easier to consistently find quality grapefruits than oranges. Also, during the winter I’m amazed at how inexpensive grapefruits are—sometimes just 5 for a dollar. I find that a thin-skinned grapefruit produces loads of juice compared to an orange that can often have very thick skin and little flesh. I’m in Canada so this may not be true if you live in the southern US. I juice 6 grapefruits, add them to two 20 ounce Rubbermaid water bottles, and then top them up with orange juice. It’s liquid sunshine in a bottle which is a great antidote for our long cold winters.