Thursday, June 27, 2013

Culinary arts lesson #4: Don't forget to bring chemistry in the kitchen.

Back in college, I had a classmate whose hands got exposed to phenol, a chemical that transforms into phenolic acid (which causes nasty burns) when mixed with water. Because of this incident -- plus a few others that involved my MCB 101 classmates almost burning the lab down -- one professor remarked: " Don't forget to connect what you've learned in Chemistry class to what you're doing in other subjects". Then, I wasn't integrating ideas from different disciplines, except Human Physiology (HFDS 12, if I remember correctly) and Microbial Physiology (MCB 120) with Biochemistry (Chem 160.1).

As I attend the Fundamentals of Culinary Arts in ISCAHM these days, I notice that the instructors -- Chef Kenneth, Chef Joey, Chef Manoj, and Chef Rudolf -- are emphasizing the science behind the way food is prepared and cooked. I find it fascinating that the things I had learned in college, which I've always treated as concepts I only keep in school, are actually applicable in the kitchen. 

How? Here are a few examples...

Solvents, such as water, always move from regions of low solute concentration to areas of high solute concentration in order to maintain equal concentration between the two regions. In the cases of biological systems, the movement of water may occur through semi-permeable materials (such as the cell membrane).

In preparing food, this movement of water is the very reason why salt is added to fruits and vegetables during mise-en-place. Cucumbers and pineapples are two of these items that have very high moisture content. For certain dishes, these fruits have to be really dry and so salt is added to them to draw out the moisture from the plant cells. Osmosis is also the reason why salt is added just before meat is cooked (i.e., grilling and frying): the meat needs to remain moist; if the salt is added to early (or if the marinade is really salty) water is removed unintentionally and the meat eventually becomes dry.

Starch chemistry and functional properties
Potatoes and cereals are some of the major sources of peoples' caloric intakes. The calories (carbohydrates) come in the form of starch. There are two forms of starch, amylose and amylopectin; they are basically made up of glucose molecules that are attached differently: amylose is made up of glucose units stuck together in a linear fashion while amylopectin is composed of glucose units arranged in a branched pattern. The amylose content is known to affect the texture of cooked starchy foods while amylopectin structure affects their cooking time.

The starch composition of potatoes, as Chef Kenneth mentioned in one of our classes, defines how we should use the potatoes. There are those that are good for baking and that are good for boiling; then there are "general purpose" potatoes like the ones sold here in the Philippines. Chef Manoj, on the other hand, talks about different water ratios when cooking Basmati and jasmine rice types on stove tops and in rice cookers.

Back in the day when I was a Chemistry student, my teachers were discussing the different types of mixtures (such as colloids, suspensions, solutions, and emulsions). In class, I've encountered emulsions and suspensions so far. Chef Kenneth taught us how to make mayonnaise (an emulsion of oil and egg yolk), and vinaigrette (an emulsion of olive oil and vinegar) during the Salads and Dressings class. Chef Rudolf taught us how to make Hollandaise sauce (emulsion of egg yolk and butter) in our Sauces class. Chef Manoj emphasized the importance of cornstarch suspended in water as a thickening agent for the chicken teriyaki sauce. 

If there's one thing I've learned so far, it is this: Culinary arts is scientific too!