White asparagus & blue potatoes: Veggie color variations explained


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What's going on with that freaky white asparagus and neon-purple cauliflower? Believe it or not, this is creative agriculture at work — and doesn’t have anything to do with genetic modifications or additives. We investigated the science behind these natural phenomena, examining just how much the various color varieties differ in the way they’re farmed, their nutrition and their taste.  


Purple and blue potatoes

You know those awesome bright blue potato chips Jet Blue serves on its flights? The Terra Chip company uses potatoes that really start out that blue. The vibrant color you see in purple and blue potatoes is due to healthy pigments known as carotenoids and flavonoids, which are associated with a reduced risk of cancer and a lower mortality rate from numerous diseases.

While all potatoes are nutritious — they’re a good source of complex carbohydrates, potassium, vitamin C, folic acid and iron — the more colorful ones contain the highest amount of carotenoids and flavonoids. Those blue Terra chips get their cool color from the flavonoids in particular. According to Whole Foods, the darker the starchy yellow flesh of the yellow potato, the greater quantity of carotenoids, including beta-carotene — and in some cases, lutein.  


White asparagus

You may have noticed ghost-white stalks of asparagus at the market before. It looks exactly the same as its green counterpart but for the color — and nutritionally, they’re very similar. Though studies have shown white asparagus may contain fewer antioxidants than green, both kinds are a very good source of protein, vitamins A and C, folate and potassium.

White asparagus gets its color — or lack thereof — from the strange way it’s grown: It’s covered with mulch and plastic to block out all sunlight, so photosynthesis never occurs and the crop’s chlorophyll pigment never absorbs enough sunlight to turn it green.

While the taste of these two asparagus varieties is comparable, white asparagus has a slightly more delicate flavor, with thicker, bitter skin.  


Orange and purple cauliflower

Cauliflower breeders fairly recently discovered a way to drastically alter the color of the vegetable without genetically modifying it. It took decades, but they used traditional selective breeding to produce the unusually bright orange and purple varieties you’ve probably seen in stores.

Orange and purple cauliflower generally taste the same as white, but the different varieties vary in nutrients. Part of the reason orange cauliflower is orange is because it contains a high concentration of beta-carotene, a form of vitamin A contained in carrots, pumpkins and sweet potatoes that promotes healthy skin. In fact, the orange variety contains 25 times the amount of beta-carotene found in the normal white variety.  


Colorful heirloom tomatoes

If you’ve ever been to a farmers market, you’ve noticed that heirloom tomatoes barely resemble the ones you see in the grocery — they’re odd shapes and sizes, and they come in a range of colors. As you may have guessed, this is because the mass food industry realized that consumers prefer “pretty,” so they’ve altered their tomatoes to look as perfectly round and as intensely red as possible.

In order to produce tomatoes with that bright red color, tomato breeders bred them with a specific gene — unfortunately, this gene also diminishes flavor and results in tomatoes’ lower concentrations of carotenoids.

This is yet another reason — in addition to low cost, organic produce and helping local farmers — to go to the farmers market. Heirloom tomatoes might not look as perfect, but they offer more flavor and health benefits.  


Green, red, orange & yellow bell peppers

We always want to grab the beautiful red, orange and yellow bell peppers when shopping for dinner ingredients, but we so often end up with green bell peppers because of the price. It turns out there’s a very logical reason green bell peppers are cheaper than their colorful counterparts: They don’t take as long to grow.

The reason bell peppers come in different colors is because they’re harvested at different times, according to Whole Foods. Green peppers are plucked from the plant before they’re fully ripe. If left on the plant, they usually change to yellow-orange and then red.

This also explains the slight difference in taste. Because the pepper’s sugar content increases at the fruit ripens on the plant, the green varieties are the least sweet and have a sharper, almost bitter, taste.

All four colors have their own nutritional benefits: Green peppers are packed with chlorophyll; yellow peppers contain plenty of lutein and zeaxanthin carotenoids; orange peppers offer alpha-, beta- and gamm-carotene; and red peppers provide lycopene and astaxanthin (two other carotenoids).