Cooking Onions: Flavor Chemistry Changes

Chemistry, Food
[caption id="attachment_21597" align="alignright" width="480"] M-m-m, Sweet![/caption] An onion, particularly a yellow or Bermuda onion possesses a strong, perhaps acrid flavor. And its aroma? You are likely to weep when you chop one! Yet, if you take that same onion and fry it, it can be just as fragrant and sweet as ever you could wish. What happened? It's a matter of chemistry. From Wild to Tame The flavor of a raw onion is the product of a number of complex organic substances. The ingredient primarily responsible for tear-ing, is (Z)-propanethial-S-oxide. This compound, a lachrymator (tear-producing gas), is produced when onion cell walls are broken by slicing and chopping. Does frying result in a decrease of this chemical, resulting in sweetness? Does this compound decompose on frying to producing the sweetness?1…
Read More

What is Carrageenan?

[caption id="attachment_10160" align="alignright" width="480"] Cultivated Chondrus crispus seaweed.[/caption] Carrageenan is a thickening agent and stabilizer. It is derived from seaweed. Would you believe it is frequently used in dairy products? One example is commercially formulated chocolate milk. Thickening the base imparts a feeling of creaminess to the milk. And yes, this seaweed derived thickener is a major ingredient in less expensive (read: cheap) brands of ice cream. Vegetarians Its origin makes carrageenan a natural for vegetarian products. One historically important variety comes from Chondrus crispus seaweed. It is very often called Irish Moss. It replaces animal based gelatin. Another well known form comes from the seaweed Gigartina stellata (which is called Carrageen Moss). Chemically Chemically, the thickener is not simply one substance. It is a whole family of substances, the…
Read More