Explain why food changes color when cooked

Beef is brown, shrimp is red . all have causes.

Explain why food changes color when cooked

Recently, netizens are roaring up to the photo movement: white corn after boiling turns yellow with lots of ideas such as: red beef but turns brown, gray shrimp turns red . .

Photos are being shared wildly.

Ignoring the humor factor, have you ever wondered why the food when cooked is discolored? Although it is considered by many to be obvious, not everyone can answer this.

From the reaction to create brown and smell Maillard .

For those who learn food chemistry, cooking together is just a synthesis of chemical reactions. The reactions are caused by changes in temperature, water, pH of the material .

Mailard reaction makes the meat turn into a very attractive brown color.

One of the most important reactions in cooking is the Maillard reaction - also known as 'browning reaction' in processing.

Specifically, when the food temperature reaches over 140 degrees C, amino acids and reducing sugar in food will be rearranged. The bonding rings formed then reflect light into the eyes into brown.

Toast is brown, also thanks to Maillard reaction.

Maillard reactions occur for nearly all foods, including brown toast, brown beef, yellow bumps, corn from white to yellow . Based on temperature and Moisture, dishes will have different colors and flavors.

. to more specific examples

However, the Maillard reaction is not the only thing that makes food discolored during processing. For example, beef becomes brown, but chicken and pork become white .

Red beef turns brown when processed.

The reason that beef can be browned is by the Mailard reaction, in beef containing myoglobin - which makes red for beef or other red meats. Myoglobin is a protein that stores oxygen in muscles, containing iron atoms like hemoglobin in red blood cells.

Under normal conditions, the iron in myoglobin comes in contact with oxygen to form red iron (II) oxide. However, when there is an effect of temperature, iron oxide (II) becomes brown (III), which turns the color of the meat. Meanwhile, white meat such as chicken, pig . contains less myoglobin, so when cooking, it becomes white.

But what about shrimp and crab? Why do normal crabs and shrimps appear green, gray . but when they are cooked, all of them turn red?

Experts explain that in fact , these species already have red pigments in the shell from a chemical called astaxantin , but they are normally obscured by another chemical - crustacyanin .

Under the influence of temperature, crustacyanin will denaturation, breaking the inherent chemical structure and then giving way to "shine" astaxantin .

Some green vegetables may also discolour when processed, which is because chlorophyll-chlorophyl l - in vegetables with metamorphosis. When exposed to high temperatures, magnesium atoms in chlorophyll will be replaced by hydrogen, causing it to turn into gray-green porphyrin.