Blue Tofu (healthy, gluten free, high protein + synthetic dye free)

Here’s a Food Science fact: did you know that there are no naturally occurring blue foods on Earth? Yep, it’s true. According to one of my Food Science professors, due to the fact that blue light reflects poorly on green leaves during photosynthesis, rarely do natural foods exude the color blue. Oh, and before you say that blueberries are blue, they’re purple. Just smash some on a white plate. See the purple juice? There’s your proof!

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Truth be told, I was relatively shocked when I first heard my professor’s statement. I could have sworn that there are actually real foods from this planet that are blue and not actually purple or green of any sort. But the more I thought about it, the more truth I unraveled from this articulation. Most blue-looking fruits and vegetables are actually more of a deep purple, red, or even black.

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At the same time, I read a few blog posts and some YouTube videos dedicated to plant-based food dyes. Here’s the quick list of my favorites:

  1. I love this kid-friendly take on making plant dyes out of flowers and certain fruits and vegetables such as beets, grapes, and spinach. Now I know EXACTLY what to do with my leftover onion skins!
  2. Proof that you can dye your foods blue without any synthetic or artificial food dyes. Blue spirulina and blue goji berries? MUST FIND.
  3. Read this visually beautiful, specifically articulated, and easily understandable tutorial on how to create and succeed with natural food dyes out of all kinds of ingredients–many that you already have in your kitchen!–such as matcha, cocoa powder, turmeric, parsley, carrots, blueberries, and sweet potatoes!
  4. Absolutely adore Willa’s “soil-to-studio” food dyes that use the same method, but can be used with almost anything! The colorings made from black beans and rosemary are absolutely gorgeous. I’m seriously so inspired.
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Not until now have I realized how incredibly fun and rewarding it is to experiment with making your food way more colorful out of other vibrantly colorful foods! Admittedly, some wholesome food are just pretty sad-looking when plain without sauce or seasoning. Take tofu. It’s literally the edible blank canvas: three-dimensional, rectangular, white, and absorbant of anything you flavor it with. But guys, this recipe is a HUGE. WIN.

Drawing inspiration from all my resources (including the links listed above), I had to take advantage of red cabbage and put its coloring ability to the test. How vibrant is the resulting color? While it really depends on how long you soak the cabbage leaves in the water, the shade of blue is almost always POPPING. The water transforms from a transparent liquid to a deep, vivid, and gorgeous indigo dye that works magnificently in this recipe. I decided to use the final dye as a marinade for my firm tofu and see if the dye would remain intact after cooking as well as whether any changes in color would occur. Will the tofu become purple, black, brown, or would it just remain blue? Drum-roll please: post pan-frying, the tofu come out as these stunning vibrantly sky blue, almost lavender, rectangles with golden-brown specks.

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Important to note: it is strongly discouraged from adding any other ingredient into the cabbage dye. This is because you run the risk of altering the color of the dye from chemical reactions. For instance, any acidic ingredient such as lemon juice will transform your indigo color to a red or deep magenta. Baking soda will turn the dye green. Adding a starch such as flour or cornstarch will give you a pale pink hue. If you want to use any sauces or seasonings, be sure to do so after you cook the tofu.

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Evidently, this is why I love Food Science. You utilize your knowledge of food chemistry, culinary ability, sensory, and processing to create something magical. What’s even better? You get to EAT your creations after some praising time. Who wouldn’t want a delicious meal after a science experiment?

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Yes, everyone. Y’all are scientists. Cooking is science. Okay, maybe pouring cereal over milk or eating bread slices straight out of the polyethylene and polypropylene bags aren’t considered science in terms of cooking. But you still perform digestion after eating, which are both biochemical reactions. You’re basically a walking science experiment in that case.

Ba-chooooooooooo. *blows my own mind*

RECIPE (serves 2-3)

  • 1 block of firm tofu
  • 2 cups of red cabbage
  • 4 cups of water
  • Cooking spray or any cooking oil
  • Additional seasonings and/or flavorings to serve with


  1. Remove the tofu from its packaging.
  2. Completely wrap the tofu in paper towels or a cloth.
  3. Using a paperweight or tray, press the tofu to squeeze out any liquid. Do not over-press.
  4. Cut the tofu into cubes, slices, or strips. Set aside.
  5. Bring the water to a boil in a saucepan.
  6. When the water just comes to a boil, reduce the high heat to low-medium, and soak the cabbage in the water for at least ten minutes, or until the water obtains a deep blue color. Alternatively, you can continue to boil the cabbage, but the cabbage will just be more soggy.
  7. After ten minutes, save the water in a tin, deep dish, or medium bowl while straining the cabbage. Set the cabbage aside for later purposes (I like eating it with the tofu!).
  8. Marinade the tofu in one cup of the dyed water for at least five minutes, flipping them around if necessary. The longer the marinading time, the deeper the color.
  9. When ready to cook the tofu, lightly coat a skillet with the spray or oil on medium heat.
  10. Pan-fry the tofu once the skillet is very warm, waiting one to two minutes on each side before flipping periodically.
  11. Serve warm after the tofu has been prepared to your liking.

Do you agree or disagree that there are no naturally-occurring blue foods? Have you ever tried experimenting with natural food dye?

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