Food and blue are toxic吗? -healthy recipes and snacks

User Ah Fung question: I liked the deep colors of vegetables to eat. Such as carrots, West blue flowers and purple cabbage. However, recently I bought a purple cabbage, found some anomalies: cheuk with boiling water half a minute to one minute after the color of water in particular blue, as deep as blue ink pen, which is very terrible. I remember a few years ago, the color is not so deep. So, I suspect that the "illegal farmers" in purple cabbage growth process chemicals used in dyes. Do not know whether my conjecture makes sense? Person or people, how to identify it is indeed a natural food color? Now I also敢吃Purple Cabbage吗?

In fact, this problem is not the first time heard. A day go canteen to eat Peking University, students ask me: This is Beijing's紫米how soft cake are blue? Ah really terrible! Do not let the dye pigment are!

shake my head and said: If you want to dye, who will specially dyed it blue? Why not direct dyed it purple? In fact, this is a normal phenomenon. However, anthocyanins are food substances at different pH just under Change.

(Say the truth, at my elementary school before they know it, because when the 6-year-old saw a "scientific experiment", which says This Fantastic change, then I am fascinated. - not to mention早慧matter, anyway, everyone has felt the Ran Min. later taught food chemistry class, the natural pigment in Chapter 1, Procyanidins must talk about this period are the .)

To verify that this pattern may be a simple test. Get a purple cabbage leaf, put it to shred. It is purple, right? Now put it in tap water, coupled with some baking soda. You will see, leaves the color of the blue.

want to know the north are basically alkaline water, pH value of Beijing's drinking water at about 8, groundwater higher. So leaves will become a blue-violet purple. When will usually make pasta add a little alkali, to do the soft porous cake, but also must add baking powder, which has baking soda. Therefore, Beijing University of soft cake are blue-violet, which is not strange, and toxic, are hard not to adulterate the top. Rather, the absence of such changes are possible only by the color of dye, because there is no artificial pigment discoloration such wonderful responses from the public.

when fried purple cabbage discoloration, but also because one of the heating so that volatile organic acids, acid drop, they are moving the color to blue. If you want the color of vegetables look good, is too easy - just add enough vinegar! Regardless of vinegar rice vinegar, can let the color of purple cabbage purple into a good-looking than the original but also red.

restaurants on the use of this rule, using purple cabbage to make the "big side dishes." Since such a cold dish is bound to be mixed加醋, purple cabbage color always seems Hongyan beauty, great peach-Yan if the feeling ... ...

Finally give students food review click: Procyanidins at different pH values have four kinds of forms of existence, under the acidic condition flower sheep salt form (He has sheep, not beat) a bright red, when subalkalic rearrangement for the quinone-type structure, showing the blue. Near neutral showed a mixture of purple red and blue. Under alkaline Procyanidins easily into chalcone-type or intended to be colorless basic structure, but under the color of acid remained relatively stable.