Soon, Fall Will Be GMO Apple Season Too
If you live in the Western United States, the Arctic Fuji may be coming soon to a store near you. It’s the latest of three genetically modified apple cultivars (the others are the Arctic Golden Delicious and the Arctic Granny Smith) that were developed by Okanagan Specialty Fruits, in British Columbia, and received USDA approval last fall.
What we now must start thinking of as “regular,” or non-GMO, Fuji apples were introduced from Japan to the U.S. in the 1980s. The cultivar’s distinguished American pedigree includes the Ralls Janet; named in 1793 by Thomas Jefferson, it has great flavor and texture and is an excellent keeper.
With “Arctic” in the name, you might presume that this new Fuji incarnation was genetically modified for cold hardiness, perhaps with antifreeze proteins from fish swimming in polar waters, but nope—nonbrowning properties are what bioresource engineer Neal Carter, founder and president of Okanagan, is after. The fruit has been altered not by adding a gene, as with some other GMOs, but by suppressing the gene that controls the enzyme polyphenol oxidase, the primary cause of enzymatic browning.
Enzymatic browning—as opposed to caramelization and the Maillard reaction, two nonenzymatic forms of browning—happens to a variety of fruits and vegetables when they are cut or bruised so that oxygen is introduced into the injured plant tissue. If your kitchen tasks ever involve cutting potatoes, artichokes, mushrooms, or lettuce; making guacamole or pesto; or throwing out or composting a child’s untouched sliced banana or pear because it’s “yucky,” you know what I’m talking about.
“When oxygen is present in cells, polyphenol oxidase (PPO) enzymes in the chloroplasts rapidly oxidize phenolic compounds naturally present in the apple tissues to o-quinones, colorless precursors to brown-colored secondary products,” Lynne McLandsborough, a professor of food science at the University of Massachusetts Amherst, told Scientific American. “O-quinones then produce the well documented brown color by reacting to form compounds with amino acids or proteins, or they self-assemble to make polymers.”
Browning by PPO is not always undesirable, McLandsborough added, noting that the familiar brown color of tea, coffee, and cocoa is developed by PPO enzymatic browning during processing. But when it comes to produce, it’s been estimated that a gobsmacking 50 percent of the world’s fruit and vegetable crops is lost because of postharvest enzymatic browning, which is visually unappealing (think of those premade California rolls that languish in a deli’s take-out case) and results in the loss of antioxidants as well as flavor and texture.
If you think that some apple varieties brown more quickly than others, it’s not your imagination. Depending on the cultivar, an apple’s levels of PPO activity and phenolic compounds can vary. If I were to slice apples for a fruit salad or a cheese plate, for example, I’d opt for Granny Smith, Calville Blanc, Cameo, Ginger Gold, or Cortland (the most resistant of them all to browning). “In addition, a tissue’s PPO level can vary depending on growing conditions and fruit maturity,” McLandsborough explained.
“Whatever,” you interrupt. “All I know is that I wouldn’t touch a G.M. apple with a 10-foot pole.”
I’m right there with you. I can see why commercial kitchens and the flourishing “fresh-cut” industry, which typically rely on a calcium ascorbate dip to reduce browning, might prefer to skip a processing step and use a nonbrowning apple instead—but give me the apples from my local orchards any day. (The United States is a treasure trove of non-GMO apple varieties, and here’s a handy cheat sheet for you.) I’ll sprinkle the sliced fruit with lemon juice, which slows down but does not eliminate the browning, and hope for the best.
The reason lemon juice helps keep apple slices from discoloring, by the way, is that it’s full of ascorbic acid (aka vitamin C), which essentially creates a barrier between the cut plant cells and the air: The oxygen will react with the ascorbic acid before it’ll react with the enzyme in the fruit. (Once the ascorbic acid gets used up, however, browning will occur.) The low pH level of lemon juice also helps prevent browning. It’s in the 2.0 range, and the enzyme is inactivated below a pH level of 3.0.
This time of year, one of my go-to “home alone” suppers is an apple with a piece of good farmhouse cheddar. At some point this week, the mix of Macoun, Gala, and lord knows what else in the crisper drawer is going to be cooked down into a complexly flavored applesauce (a blend of a few varieties is the key). It’ll be wonderful in the morning stirred into plain Greek yogurt or oatmeal, or with skillet pork chops at suppertime.
What I have in mind for this evening’s scratch supper, though, are fried apples, which aren’t deep-fried but simply sliced and sautéed in butter. I like to get them working on a back burner just as I’m pulling everything else together. By the time they’re browned and a little crisp on the outside, they’re creamy inside. They make a fabulous side to pork, ham, sausages, or roast chicken.