Orange juice science

Reading ingredients in the quintessential American breakfast drink feels good. It’s simply “orange juice.” I get a mental picture of a factory smushing the tangy orange balls until nothing else drips out. Then it strains some or all of the pulp and bottles the bright, vitamin C-filled juice. Three steps. At least, that was the picture I had until I overheard a conversation on my plane ride back from Science Online last month. A woman from the orange juice industry was explaining something I never thought to wonder about.

“You know how oranges taste different at different times of year?” she asked her seat partner.

“Yes,” I thought. There’s nothing more disappointing than a tasteless, or worse, bitter, orange.

“Well, that makes orange juice taste different at different times of year too,” she said.

“That makes sense,” I thought. And then she came out with the zinger.

“Except that every bottle of orange juice you’ll ever buy at the store tastes exactly the same.”

And she’s right. How could this  be? Luckily, she didn’t leave me in suspense for long. There are manufacturers, she explained, that spend their days juicing oranges and then siphoning off all possible flavor compounds from the juice and selling them in pure, concentrated form. When juice makers hit the citrus offseason, and the juice doesn’t taste as nice, they test their flavor compounds and simply open up which ever hydrocarbon, alcohol, aldehyde, and ester is missing and dump it in.

Though my taste buds are happy, I felt slightly disillusioned about the ingredients on my orange juice bottle after these few minutes of eavesdropping. My first impulse, of course, was to army crawl into a juice factory and stealthily factcheck this overheard revelation. But since I have access to Google and scholarly databases, I am investigating from my living room instead, with an orange in hand to add credibility.

An old UC-San Diego project website on increasing orange juice flavor quality confirms that my mystery source’s explanation is at least plausible. Orange juice concentrate, the site states, is not only manipulated when the fruit is out of season, it happens simply because the flavor compounds are affected by processing. 95% of juice is water and the remaining 5% is mostly volatile flavor compounds that are easily lost during pasteurization and evaporation. The site states that: “One method for improving the quality is to strip the aromas from the in going raw juice stream before processing and to feed them back into the final product.”

This combined with several studies ranging in publication from 1978 to 2011 on the “volatile flavor compounds” in orange juice have left me at the conclusion that indeed, my orange juice is not simply the result of smushing. The healthy-tasting liquid has been dismantled and then rebuilt so my tongue’s expectations are exactly satisfied. This makes me wonder why freshly-squeezed juice is more expensive than chemically-disassembled-and-then-reassembled juice. Lucky for me this blog is called eating science, not eating economics. I encourage any economist reading to write a complementary post called “orange juice economics.”

Photo credits: orange shared from and orange juice by Ian Britton.


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