This week’s post is a re-post from a short lived tumblr account of mine. I learned quickly that my writing is usually too long to tumbl deftly. Enjoy.
You guys remember Johnny Appleseed?
The man who travelled across America in the early 19th century, flinging apple seeds in his wake, establishing orchards full of the shining red fruit for people to eat?
It’s a nice story. But despite what you may have been told in elementary school, Appleseed’s apples were never intended for direct human consumption. As Michael Pollan wonderfully details in his book, The Botany of Desire, Applespeed was in it for the booze, his apples destined to become alcoholic cider—the main use for any seed-grown apple at the time.
For the most part, apples grown from seeds taste nothing like the grocery store varieties, with most flavors being unsavory. Fermenting the fruit into cider is about the only way large quantities of seed-raised apples can be made profitable (and consumable), which is exactly what Appleseed had in mind.
But apples are good for plenty of uses beyond boozing, and varieties with predictable colors, shape and flavorful taste are easily found in most supermarkets. However, these apples didn’t sprout directly from seed-sowed trees. They’re genetically engineered clones.
For thousands of years people have been cloning apples by grafting, a technique that cuts a portion of one tree with desirable characteristics and sticks it to another host tree. If all goes to plan, the transplanted tree survives and continues to grow and produce fruit, not worrying it hijacked the lower-half of a different plant. (Plants are pretty OK with this, you can even fuse tomato and potato plants into a single entity that makes tubers below and fruits above!)
In effect, many of the most well-known apple varieties are clones of apples that were first-born hundreds of years ago. The Red Delicious was first developed in 1880, the McIntosh in 1811 and Granny Smith in 1868. Genetic cloning via grafting has kept these apples going for centuries. And now a biotechnology company is hoping to use more precise measures than the low-tech grafting to genetically engineer apples to be even more to our liking.
The Canadian biotech firm Okanagan Specialty Fruits Inc. has made an apple that’s resistant to browning. They’re called “Arctic Apples,” because of the ability of apple slices to retain bright white flesh, even when left to idle on the counter top for a few hours.
Unlike conventional selection techniques, Okanagan’s apples were made to order. They contain a transgenic gene (it’s a mix of four known plant genes) that reduces expression of the enzyme, called polyphenol oxidase or PPO for short, which instigates the browning reaction when the apple is cut or bruised. According to Okanagan’s website, the transgenic apples (they come in three varieties: Granny Smith, Golden Delicious, and Fuji) produce less than 10 percent of the enzyme than conventional cultivars. With so little enzyme present, the apple remains “arctic white” until other forces of nature kick in, like molding or bruising, which work on a longer time scale.
The result of genetic tinkering is apples with “no enzymatic browning, no ‘yuck’ factor to discourage you from enjoying that delicious apple,” according to Okanagan.
I am a total advocate for concept genetic engineering technology, but personally, when I first heard of Arctic Applies I thought they were an over-the-top solution for a minuscule problem. After all, all you need to prevent browning is a small squeeze of lemon juice.
But then I started to wonder: Besides spoiling an Instagram shot of your fruit salad (a filter can probably fix that anyway), what’s role of PPO in first place? What other attributes could Arctic Apples have besides being non-browning?
PPO is ubiquitous in plants and is released from cell vacuoles following trauma. Once released, PPOs oxidize a class of nutrients called phenols, with a side effect of this oxidation being browning. The exacts of why this chemical cascade happens in the first place isn’t well known and is a topic of diverse study (though it’s thought that plant defense might be a major reason). But by oxidizing phenols, PPO deactivates an important class of antioxidants thought to help promote and preserve cell-health.
Therefore, by inhibiting browning, Arctic Apples may also help preserve nutritional value. This is a second point that Okanagan makes on its site.
I haven’t been able to find any research as of now comparing the active phenol concentration between fresh apples and brown apples, and I imagine it’s something that’s hard to measure—a likely reason why this point is often upstaged by the Arctic Apple’s aesthetics.
Still, nutrition and beauty aside, I still wonder how much of a market there is for Arctic Apples. I couldn’t find any stats on the apple eating habits of Americans, or any other nationality for that matter, but I assume most people like their fruit fresh—in a state where browning or phenol degradation isn’t much of an issue. And for better or worse, the whole organic/anti-GMO popularity will likely have consumers passing by Arctic Apples if they’re outwardly identified as GM.
Either way, the Arctics fit into a long history of humans molding apples to meet our desires; grafting has expanded to include genetic material as well as tree limbs. It will be interesting to see if this particular apple is desired (conventional apples are already best selling fruit.) and what other effects, if any, may come from the added gene.
One more thing—You can’t currently buy Arctic Applies. Right now they’re under evaluation by the USDA, CFIA, Health Canada and the FDA. I give Okanagan props for the FDA evaluation because under current law it’s completely unnecessary. I presume a successful FDA evaluation could help alleviate worries surrounding this potentially new iteration of America’s most beloved fruit.
Pictured at top: a diagram for grafting. Courtesy of http://chestofbooks.com/
RE: Science 