How to Preserve Vegetable Pigments

Thank you for a terrific class!

Good one and welcome back. You were missed.

Nice lesson. And very useful now that summer approaches! Don't forget your suntan lotion everyone, we don't want any unwanted Enzymatic browning;p

Thank you for the great lesson. Rouxbe is great as always!!

I do, however, have a question. Often, I roast my cauliflower with olive/canola/safflower oil and what ever herb I am inclined to that particular day. If I were to add an acid (say in a spray bottle to disperse it evenly) in order to keep the cauliflower white(r) when roasting would this work? Is it even desirable? I happen to love the roasted flavor, but sometimes the color is unappealing. I want the brown roasted part, but on a whiter background. Gosh, one would think I was referring to a painting. There is some thing wrong with us foodies. Seriously. And in keeping with Iain G, you put suntan lotion on your face, arms, etc. DON'T FORGET THE TOPS OF YOUR FEET! A friend developed skin cancer in that location recently, who knew?

I like to steam cauliflower and other vegetables. If steaming a veggie that benefits from an acid cooking environment, should the acid be in the steaming water or applied to the vegetable?

We will cover other cooking methods for veggies, such as steaming, roasting and braising down the road, even sous vide hopefully.

Unless cooking the vegetable in a liquid medium, adding acids topically during the cooking won't really benefit. Adding an acid to the steaming water won't benefit the pigment that much. Roasting will alter some pigments, but not as dramatically as simmering, and create desired caramelization.

So if not simmering or blanching, don't go out of the way to put an acid on your food, unless you want that flavour there.

Thank you very much, this lesson is really helpful.

I suspected an acid spray would not really help after a little investigation in my various cookbooks and on the Net, but KNEW I'd receive an informed reply here at Rouxbe. My roasted cauliflower comes out very nice; I'm working on sauces instead of herbs now as I need to keep it interesting and the BF prefers more complex food. I have done that with broccolini already, but do not think it will convert from green to white vegatable, although the theory will. Once again Tony M thank you much.

Is there any way that I can make purple mashed potatoes ?? I think it will look really good but I heard that after boiling purples potatoes they tend to loose their beautiful color ...

To make purple mashed potatoes is really just the same as making regular mashed potatoes. The darker the purple the more deep the color will be, but when cooked they usually do loose some color. I personally have never been able to keep that deep color when cooked.

Here is a recipe from another blog site for purple mashed potatoes - http://www.restaurantwidow.com/2007/07/pretty-purple-p.html
Here's another link for purple potato gratin with bacon - http://www.eatingoutloud.com/2008/02/purple-potato-gratin-with-bacon.html

Happy Cooking!

Thank you very much I'll try that ...

Do you think that steaming would retain the color in purple potatoes? I know it's a nice way to prepare taters for mashing.

I think that steaming would help to retain some of the color because the potatoes will be will be in less water.

Another eye opening lesson, thanks!

I have a question. Why in almost all cooking, e.g. vegetables, pasta, et al is one told to begin with cold water? I asked that question in Tuscany during a cooking class and the answer was something about hot water might have more "rust from the pipes" than would the cold water. I think there was a language problem in the Q and A. Please give me an explanation that makes sense, or is it just habit?

The reason for this is - as you said - because water is heated by hot metal which can lend water a metallic taste which is undesirable, always use cold water, some times you actually need to use filtered or bottled water

Despite the language barrier, your Tuscan teacher was correct. Hot water can absorb off flavors from sitting in heating tanks and pipes. Depending on where you live and how old your hot water system is, this can be more of an issue for some. Here at Rouxbe, we prefer to start with cold water (especially when making stock or cooking pasta/vegetables).

There is a lot of discussion on the subject (see this thread on Chowhound). Hope this helps.

According to "The Silver Spoon" in it's "Cooking Terms" section there is the following:

Add While Cold
To add an ingredient to a liquid or sauce before heating. For example, meat it put in cold water when the flavour of the stock is more important than that of the meat.

Add While hot
To add an ingredient to a hot or boiling liquid or sauce. For example, meat is put in hot water when the flavour of the meat is more important than that of the stock.

I've always taken this to mean that starting from cold is liable to leach more flavour out of the ingredient added (ie. if you were making stock, you'd want to start with cold water)

I think that you may be misunderstanding the response above. We were referring to the water that is coming from the tap (before the cooking even starts). We were saying that it is best to start with cold tap water rather than hot tap water, as hot tap water can sometimes have off flavors from the pipes.

You are correct in what you were saying about adding ingredients to cold or hot water.

Hope this clears things up for you. Cheers!

Is there method to preserve exposed bananas for a short time.
Relative to the veggie preservation video I should submerge them in a "acid" water. Is this correct?

Carlos

If you squeeze a bit of lemon juie onto the bananas, like when making a fruit salad, it will help keep them from going too brown; however eventually they will go mushy. I would not suggest that you submerge them in an acid water as this will only make them mushy. For the best results, peel and eat or use the banana immediately. Cheers!

I am still a bit confused about the acid matter with lid on and lid out. What is the difference between the natural acids of green vegetables that cannot condensate with the lid on, and the acid added to the liquid with other pigment families, that can condensate with the lid on?

Green veg pigment, chlorophyll, reacts adversely with all acids - all other pigments do not, in fact most welcome it. When cooking veg in water, some acids are released by the veg at the surface level. With a lid on, these acids condensate and can denature the green pigment. Other pigments are not affected, but often require additional concentration of acids (especially white and red pigments) to preserve their colour.

thanks a lot....it helps me to my culinary lesson!!!

thank you great lesson

Well, it's true. Yes, you can teach an old dog new tricks. I've been cooking for 40 years and never knew this. Just in time for the next 40. Thanks so much!!

r there any lesson for deserts?

If you search the Cooking School page you will see all of the lessons that are currently available. and if you search the Recipe page, you will find all of the instructional video recipes available. Cheers!

I just want to be sure my assumptions about peppers are correct. I believe that bell peppers are flavinoids. I assume that means that all are treated as if they were red vegetables, even though they may be yellow, green, orange, etc.

Admittedly, I rarely cook bell peppers in water, but I do have a few "Sweet and Sour" dishes that require it. In that case, my peppers always lose their vibrant colours. I am caught between wanting to have brightly coloured vegetables in the sweet & sour, and wanting to cook the peppers long enough to infuse their flavour into the sauce. Any suggestions? Maybe I should use some finely diced peppers for flavour, and add a few larger pieces near the end of the process for colour?

Peppers have all the pigments in them, but concentrations change at different times. So green have higher chlorophyll, so adding acid will discolor them; yellow and orange have higher carotene, so acid doesn't affect their pigment; and likewise for red, which have higher anthocyanins. Purple peppers, when cooked, somehow always turn an off-green.

I'd go for the red and orange peppers for your sweet and sour preparations. Your last suggestion, a good one, tells me you're thinking like a cook. Good stuff.

Is there a problem with steaming green veggies? The lid needs to be on, will the acid drip back on the veggies?

You may want to check out the lesson "How to Steam Vegetables" as we discuss this in that lesson (in particular Topic 3). Cheers!

Is there a general rule for adding salt to water for boiling/ blanching vegetables?

What is the ration Salt/ Water and does it vary for different types of vegies boiled?

Thanks for this heaven send cooking class on line, this is an overall improvement , love it.

There is a general rule for salting water when cooking vegetables in water. See the lesson on Cooking Vegetables in Water for more information. Cheers!

We bought some purple hull green beans yesterday at the farmers market. I understand that much heat at all is going to make them turn green (per the farmer). That leads me to believe I should treat them as a "green veggie" despite their color.

I guess I will try a short boil and then shock them. Thought about steaming them but I read that still changes the color.

I tried the short uncovered boil and shock but these beans changed from purple to green in 60 seconds. The shock at least kept a nice green color.

I'm thinking you might not be able to keep the pigments in this one.

Bit of an anti cooking question but are there any disadvantages of using microwaves to cook veg, in terms of taste and/or healthiness?

We do not focus on microwave cooking in our lessons; we focus on the methods taught in professional culinary schools and those include the old-fashioned ways of cooking ;) Whatever cooking medium you choose to use, the most important thing is to not overcook the vegetables. Some say that it is fine to use the microwave and that it even maintains some of the vegetables nutrients (again, providing they are not overcooked), while others would never use a microwave. The best thing you can do is to test each cooking method for yourself and see what works for you. Cheers!