How to cook a vegetable? Or how to cook food to make food taste better? That is a problem that has been studied for a long time. In 1988, a brand-new cooking method was proposed by two scientists: the scientific discipline called “molecular gastronomy.” The purpose of this new cooking method is to give people the ability not only to taste food, but also to experience food in ways other than simply flavor.
Honeydew is a common fruit. But can you imagine “drinking” a honeydew bubble? In this week’s food class, we used some “magic chemistry” to make honeydew bubbles! First, the honeydew juice was separated from the melon. Second, 1 gram of sodium alginate was added to the honeydew juice. But wait a minute, what is sodium alginate? It’s a polysaccharide (string of sugars) found in the cell walls of certain algae (alginate, right?), which looks like the structure here, except that the carboxylic acids (O=C-OH) are sodium salts:
After adding sodium alginate, the honeydew juice, which had been crystal clear (but green), became thick, as seen in the picture:
In the third step, 39 g of CaCl2 was dissolved in 655 g of water. What came next was the most important “magic” part of making honeydew bubbles: the honeydew mixture was slowly added to the CaCl2 solution to form the bubbles.
When the honeydew juice/sodium alginate mixture was added to the CaCl2 solution, a layer of gel formed outside of each honeydew drop. This gel was made of water trapped by calcium alginate, which is much less soluble than sodium alginate. That layer of precipitate made the shape of each bubble and locked the rest of the honeydew juice inside of the bubble. So the outside layer was the gel and inside was still liquid. That property can make infinite possibilities. We can make small bubbles like this:
or worms like this:
or blobs like this (oops, poured it in too quickly):
So by using chemical reagents, we can make honeydew juice into any shape we want. In other words, food chemistry gives cooking infinite possibilities.