Roundup: Food Browning

If the only ingredients in caramel are sugar and water, why does it have a taste and smell different from sugar? Why do bananas get darker as they ripen? How do caramelized onions get so sweet? Why do people have different opinions about the center of a piece of bread as opposed to its crust? Why would someone choose a browned piece of meat to a similarly cooked, but visibly lighter piece?

To understand the answers to these questions requires an explanation of the different chemical reactions involved in “food browning“. The brown color of ripe bananas, bread crust, and caramelized onions, for example, are the result of three different processes — the first is enzymatic and the other two are have to do with the rearranging or breakdown of amino acids or sugars at different temperatures.

Food browning is something that affects what we eat everyday, but if you were to look for information about it on Wikipedia back in September, you’d see a short article with no citations or references. Then it was improved by a student in Heather Tienson’s Introduction to Biochemistry class at UCLA. Now it’s three times the size, complete with citations to reliable scientific sources.

Another student in the class substantially improved Wikipedia’s biography of African American nutritional chemist and former Howard University dean, Cecile Hoover Edwards. One of the more difficult, more frequently underdeveloped parts of science biographies is the section on the person’s research contributions — yet those contributions are typically the very reason we have a biography about them in the first place. For the article on Edwards, the student focused almost entirely on building out the section on her work, such as her extensive efforts to identify low-cost foods for optimal protein production.

Other stand-out work from this class included expansions of articles on the proteins VDAC1 and SCN8A, the process of protein folding, and biographies of pharmacologist Nancy Zahniser and University of Colorado professor Natalie Ahn.

There’s a lot of great chemistry content on Wikipedia, but also a whole lot of room for improvement. Some important topics have articles which are underdeveloped, outdated, missing references, or missing altogether. Students are of an age when they’ve begun to grasp the material, but they also remember what it’s like not to have the necessary vocabulary. In that way, they are well suited to writing on Wikipedia, where they not only research class topics but communicate it to a general audience. To learn more about how to get involved, send us an email at or visit

Photo: Barangan banana Indonesia.JPG by Midori, CC BY-SA 3.0, via Wikimedia Commons.


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