By Jan Roberts-Dominguez

For The Bulletin

A fun lesson for children (and adults!) in cooking with anthocyanin:

The beautiful red and blue vegetables that contain anthocyanins (beets, red cabbage, red onions, for example) will show extrordinary color changes as the acidity varies. Check it out for yourself.

2 cups red cabbage, shredded

4 cups water (2 cups in each of two pots)

1/2 cup vinegar

1 teaspoon bicarbonate of soda (baking soda)

Boil the water in the first pot and add 1 cup of the cabbage and 1 tablespoon of vinegar. Continue boiling. The cabbage will turn reassuringly red.

Now boil the water in the second pot, add the other cup of raw cabbage and the bicarbonate of soda, bit by bit. The cabbage will turn purple, red-blue or blue. Now add the rest of the vinegar (the water will foam), and see the color change reverse itself to red.

This shows how the red-blue pigments are acid/alkalai-dependent, and they are soluble in water. If they weren’t soluble, borscht might be as colorless as vodka.

From “The Cookbook Decoder - Culinary alchemy explained,” by Arthur E. Grosser.

Just as Picasso instinctively understood the drama associated with his interpretation of the female anatomy, a cook with style knows how to make food look good. I’ve always marveled at some people’s innate sense of color and design as it comes to life in the kitchen.

A scintillating offering of green beans, glistening from just a light dressing of olive oil on a stark-white platter. Elegant and delectable in its simplicity. That’s the art of presentation. An uncanny knack of building a menu in your head that will wow a dining room full of guests based on visual components alone.

The art of cooking? Perhaps. But for every culinary Picasso, there’s a legion of cooks who can be just as successful without stewing over their lack of right-brain brilliance. All you need is a simple lesson in food science.

Indeed, brushing up on your food chemistry can do wonders for your palette — and your palate. You see, within the produce world, there are four culprits — pigments, actually — responsible for any given fruit or vegetable’s color:

• Chlorophyll is responsible for all of the greens that are so predominant in the produce world.

• Anthocyanin produces the beautiful reds and blues found in such blushing beauties as purple eggplants, berries, beets, red cabbage and red onions.

• Anthoxanthin is responsible for the creamy whites of cauliflower, parsnips, kohlrabi, white cabbage and onions.

• Carotene is the pigment in charge of the oranges and yellows in persimmons, carrots, corn, squash, sweet potatoes, peaches and a family of citrus fruits.

Understanding how these pigments react to the stresses of cooking will help you bring out the beauty within each fruit and vegetable.

Let’s begin with chlorophyll.


Remember, this is the pigment found in such green veggies as: artichokes, beet tops, broccoli, Brussels sprouts, green cabbage, celery, chard, chicory, collards, cress, dandelion greens, green beans, lima beans … the list goes on and on. Heat and acid are the enemies of chlorophyll, so if any of these vegetables are exposed to acid or heat, there’s a rapid destruction of the chlorophyll pigment, and before you know it, the vegetable starts looking bleak and miserable.

The best way to combat the acid/heat problem is to cook green vegetables as quickly as possible — without acid, of course. Already, you can see that’s a problem for such long-cook veggies as artichokes. But acclimating ourselves to the idea that cooked artichokes are a more muted green gets us over that culinary hurdle, so to speak. It would seem odd to eat a bright-green artichoke, now wouldn’t it?

But for every other green that we want to be vibrant and beautiful, consider what food scientist Shirley Corriher has to say. In her runaway best-selling cookbook from the ’90s, “Cookwise: The Hows & Whys of Successful Cooking,” she discusses the problem of cooking with chlorophyll-rich foods.

All vegetables contain acids, Corriher says. When these vegetables are heated, their cells are damaged so that the acids that were walled off from the chlorophyll in the living cells now come in contact with it. Color changes begin at that moment of contact.

That concept is something I learned from Mrs. Ireson back in Cooking 101. But all these years, I’ve thought the reaction to heat and acid was fairly swift. One minute a plate of exquisite green beans, the next, a pathetic meal of drab leftovers.

Well, think again. Corriher discovered some exciting things during her research. The amount of acid varies in vegetables, so there is a slight difference in how fast this change will take place in different vegetables.

How cool is that?

With most green vegetables, we have about seven minutes of heat before there is a major color change. So to preserve the bright-green color, don’t cook a green vegetable more than seven minutes. With larger vegetables — such as fat stalks of broccoli or big and juicy green beans — you should cut them into smaller pieces. Trim the stalks into 1½-inch florets; French-cut the green beans.

My favorite approach is blanching green vegetables in large amounts of boiling water. When blanching green vegetables, make sure the water’s boiling before adding the vegetables. Cover the pot ONLY for a moment to encourage the water to return to a boil more quickly, but then remove the lid so those volatile acids won’t wash back down into the cooking liquid. If your recipe calls for acidic ingredients such as wine, lemon juice or tomato sauce, be prepared for a dramatic change in color.

I consider blanching to be part one of a two-part process. Once blanched for three to four minutes, I whisk the pot of veggies over to the sink and strain through a colander. Then — unless the veggies are heading straight to the table — I plunge them into cold water to stop the cooking process and set the color.

At this point, the veggies can be refrigerated for several hours or overnight if necessary, and stage two (whatever procedure called for in your recipe, such as braising or sauteeing) is applied just before serving.


Like chlorophyll, this red/blue pigment is acid sensitive. But it’s not nearly as reactive as chlorophyll, so we can relax a bit. When anthocyanins come in contact with acids, exciting things do happen eventually, colorwise. During cooking, red cabbage, for example, will turn deeper red in vinegar, or bluish-purple in a less-acidic solution. One of the recipes I’ve included on this page, Sweet ’N’ Sour Red Cabbage, is a perfect example of how cooks put this principle to work to create a brightly colored dish. Without apples and vinegar — two very traditional ingredients in red cabbage recipes — the mixture would turn out grayish-lavender.

Anthocyanin pigments are also water soluble. If they weren’t, borscht would be colorless. But for centuries, cooks have known to cut their beets into tiny pieces so the dye could leach into the broth and produce a brilliant beet red soup.


This pigment is predominant in the white-toned veggies — from white cauliflower and parsnips to white and yellow onions, kohlrabi and pale-green cabbage. Like red-blue anthocyanins — and totally opposite from the chlorophylls — creamy white anthoxanthins are better off in an acidic environment. Without a splash of white wine, cream or lemon juice in the cooking liquid, these white-toned vegetables have a tendency to yellow with prolonged cooking. Try it some time, and you’ll see what I mean.

Anthoxanthins also react with iron and aluminum. Have you ever chopped an onion with an iron (instead of stainless steel) knife and noticed a gray-green residue? That’s anthoxanthin pigments reacting to the metal. So avoid iron and aluminum utensils and containers when working with these fruits and vegetables.


Unlike the other three pigments, the carotene pigment is fairly indestructible. This is the pigment that produces the bright oranges and yellows found in carrots, pumpkins, corn, sweet potatoes, winter squash, peaches, apricots, persimmons, citrus fruits, paprika, red peppers and tomatoes. And it’s as sturdy as pigments come, making it virtually indestructible where heat and acid are concerned, which means these fruits and vegetables can be overcooked — within reason — without a dramatic loss of color. Chemically speaking, this makes them rather dull. But when there are three finicky pigments to worry about, it’s a relief to know that carotenes are stable souls.

The accompanying recipes are good examples of working with some of the pigments in vegetables. And even though there are still nutrition experts who insist on cooking their greens in a covered pot with only an inch of water — for maximum vitamin retention — I don’t. Sure, they’re saving a few more B vitamins, but I’ve yet to meet the child who would willingly fork down a plateful of G.I. Joe combat-green broccoli.

As Mrs. Ireson used to say, “What do you want? A healthy family or a well-nourished garbage disposal?”

— Jan Roberts-Dominguez is a Corvallis food writer, artist and author of “Oregon Hazelnut Country, the Food, the Drink, the Spirit” and four other cookbooks. Readers can contact her by email at or obtain additional recipes and food tips on her blog at