Using natural pH indicators in cooking

[Anonymous Modernist 15855]

I'm new to the idea of molecular gastronomy. So, maybe this is old hat for many of you. But I was wondering if anyone has used natural pH indicators in their cooking? The pH scale, as you might know, measures how acidic or basic a substance is. You might remember using litmus paper in school. Of course, I'm not suggesting cooking with litmus paper... and I'm not even sure if that litmus is edible. However, there are some other amazing naturally occurring pH indicators.

The classic example is red/purple cabbage broth. Mix lemon juice into the purple-colored broth and it will turn red! But if you would add baking soda, it would turn blue! This is because of a pigment called flavin which is a molecule belonging to the anthocyanin family. Anthocyanin are very sensitive to pH and are found in a range of edible plant matter. For example, blackberries, raspberries, cherries, grapes, violet petals, and eggplant skins.

So, I'm wondering about applications for this. Since the affect is purely visual, it seems it would add flair and interest to the eating experience. For example, a simple a dessert with a anthocyanin-rich berry sauce and a small sampling of fruits of various pH.

Another idea is a vegetable broth that included eggplant skins or red cabbage; giving it a purple tint. A simple application would be place an acidic ingredient in the middle (ex. few drops of lemon juice) before serving. However, I was also thinking of including include two small bowls for washing your spoon with a slightly acidic or base solution... turning a soup bowl into a canvas.

Has anyone else played with this idea before? How have you used this? Any suggestions or pitfalls that you experienced?

[Anonymous Modernist 3840]

I can see noodles with the pH sensitive pigment in a clear broth of acid or basic nature. Where the noodles are above the surface they are a different color than where are below the surface.

[Anonymous Modernist 14040]

Honestly, I just use a digital pH probe. I am color blind, which makes litmus paper nearly useless for me. As a result, several years ago I picked up a digital probe. I keep it stored in a pH neutral solution and depending on how often I use it either recalibrate weekly or at the next use if over a week. Only takes a few minutes to calibrate and it keeps on working. It may not be as absolutely accurate as when I first bought it, but I can replace the end of it if I ever want to for fairly cheap.

[Judy Wilson]

Hi trey_rowzie,

We go over pH quite a bit in Modernist Cuisine. You might check out the sections on using a pH meter (page 2·316), the chemistry of pH (3·194), and color change (3·274-275) (plus many other sections). Like maztec, we also recommend using a pH meter.

[Anonymous Modernist 15855]

CJM,

That would be amazing to see. I wonder if the starch in the pasta would inhibit the anthocyanin pigment.

Maztec and Judy,

Thanks for the input. Yes, I agree a pH meter would be best when in the kitchen. Actually, for what I am recommending, a pH meter would be needed in preparation.

My question was more directed to how can we leverage the effect of natural pH indicators in increasing visual flair/ presentation of the food themselves. .

[Anonymous Modernist 310]

The problem is that the food is palatable on a much smaller range than what is needed for the color changes...

[Anonymous Modernist 3840]

Trey, could one make colored gel noodles that would be one color in the broth and a noticably different shade out of the broth and still taste palatable? I just ordered a spherification kit from modernist pantry, and their site says sodium alginate only gels between pH 4-10. Would you end up making a lutfisk like alkaline noodle in an acid broth? Or how about just making a gel noodle with the color indicator in it, but vary the pH as you extrude it, so it looked like a multicolor skein of yarn in the bowl? Just a few brainstorming ideas.