What are the 'natural flavors' in a fruit drink that contains no juice?

Ok... I'm going to ruin your day with this. In orange juice for instance, the process of homaginization and storage kills the flavor of orange juice, so the industry has enlisted the help of the perfume industry to help them. Each orange juice company has basically a perfume of orange flavors that it uses from the peels and rinds and biproducts that it uses to try to recreate the taste of real orange juice... It's why every orange juice brand tastes slightly different even though they are all "fresh squeezed" (btw, they are technically fresh squeezed, they're just then stored :))

If you google "orange juice flavor packs" you can see what this is talking about. The flavor packs are incidentally made out of parts of the orange, so the fda has no problem with them (sadly).

http://consumerist.com/2011/07/oj-flavor-packs.html

So to directly answer your question, you can flavor something with fruit derived perfume and call it "natural flavors"

Here's a quote from the site:

Juice companies therefore hire flavor and fragrance companies, the same ones that formulate perfumes for Dior and Calvin Klein, to engineer flavor packs to add back to the juice to make it taste fresh. Flavor packs aren't listed as an ingredient on the label because technically they are derived from orange essence and oil. Yet those in the industry will tell you that the flavor packs, whether made for reconstituted or pasteurized orange juice, resemble nothing found in nature. The packs added to juice earmarked for the North American market tend to contain high amounts of ethyl butyrate, a chemical in the fragrance of fresh squeezed orange juice that, juice companies have discovered, Americans favor.

Both natural and artificial flavors are "man-made", or manufactured. The difference is, essentially, in which chemicals are used in the process. For "natural" flavors, alcohol or oil extracted flavors are generally permitted, and heat or enzymes can be used to extract the flavors. For "artificial" flavors, solvents with a shorter history, created since the industrial age, and petroleum products may be involved. But either way, "flavors" are just chemicals, or mixes of chemicals. The rules that define the differences are fairly arbitrary. The same companies that make artificial flavors and fragrances make "natural" ones.

Once flavor compounds are discovered and isolated by flavor manufacturers, they can produce them using techniques considered natural or artificial. Some "natural" flavors may actually come from sources that don't match their namesakes; cherry, almond, peach, and apricot flavors are essentially made from the same source, as I recall, and different concentrations and contrasting items (including citric acid) affect your perception of the flavor. There's no guarantee that "natural" means "safer" or "healthier"; "natural" peach flavor may contain trace amounts of cyanide, for example, but "artificial" versions won't.

If something tastes juice-like but isn't "juice", chances are it has added citric acid (which is "natural", even though as an isolate, it, too is an industrial product), in addition to small quantities of flavor compounds, and sweeteners of some sort.

In home cooking, I've used citric acid to make some items taste brighter or more intense than they would otherwise, especially if I had some sort of fruit syrup that I considered too sweet for my purpose.

While they may employ scientists from the perfume industry, there's an important point missing here that might impact how you feel about flavor packs. As orange juice is heat processed, aroma and flavor compounds, which are volatiles (they evaporate easily, or are fat-soluble and don't stay in water based solutions well) are collected. These compounds are worth their weight in gold, basically. The orange juice right after pasteurization is pretty bland and terrible, but these volatiles are added back as a "flavor pack" to reincorporate the flavor and aroma of orange juice. and yes, the flavor packs are standardized (mixing of lots of different flavors and aromas to make sure none are really far off the ideal orange juice flavor/aroma combo), because there's a lot of variation in crops season to season because of weather, soil, other growing conditions, etc. Consumers wouldn't like it if their orange juice might be kind of good or kind of bland or flat or just different between cartons. So in my mind it's just separation of food components and then putting them back where they belong, but I come from a mindset that's kind of...pro-food processing. See below.

Source: I'm a junior level food science undergraduate student at a top ten university in the U.S. Orange juice is one of the products we talk about a lot, in terms of processing, food characteristics, and food safety. Pepisco (which owns Tropicana) is one of our primary industry connections and industry reps come talk to us about their products fairly frequently.