Chemistry can be found even in our daily lives, in activities such as cooking. By understanding the certain chemicals and the processes associated with the creation of meals, scientists can take their research even further to the benefit of humanity, such as detecting signs of food poisoning to prevent it.
Chemical reactions continuously are occurring, even when the actual cooking process may not. Foods such as apples and avocados undergo oxidation as they release a hormone within them triggers the release of ethylene gas (C₂H₄). This causes the familiar brown color if they are left outside for too long (See Figure 1). Some food companies have harnessed this hormone in order to
decrease the time it takes for food to ripen and place it in the markets sooner. For spicy or hot foods such as peppers or curry, there is a chemical called capsaicin which causes the taste that we associate with spiciness. The formula for capsaicin is:(CH3)2CHCH=CH(CH2)4CONHCH2C6H3–4–(OH)–3–(OCH3).
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| Figure 1 |
When the tongue detects the presence of this chemical, they release calcium ions, which triggers a pain signal in the brain. This is the reason why people’s tongues will burn while eating spicy foods. It has been advised to drink milk when this happens because water isn’t soluble with capsaicin. Milk/dairy products like yogurt contain casein which will effectively help ease the burning feeling. Chemical processes are also occurring when people cook meat. Meat is roughly 75% water, 20% protein, and 5% fat, with other minerals and substances in there also. When people cook raw meat, the protein coils begin to unwind as they are heated, increasing the enthalpy and therefore giving those molecules more energy to escape the bonds. The water in the meat begins to leak out as well and evaporate, which is the reason why the meat will often be smaller after it is cooked. If the meat that is being cooked is red meat, there is a protein called myoglobin that stores oxygen in red blood cells. It reacts to heat, which triggers an iron atom oxidation. The iron atoms in the protein lose an electron and this gradually changes the color from red to brown. Finally, there are also explanations due to our understanding of chemistry as to why popcorn can pop. Popcorn kernels are around 13.5% water, and when you heat the popcorn, the water in the kernel boils and turns to steam. Since you have the popcorn sealed in the pot, the pressure increases and eventually, the kernels explode. These revelations about the chemical and physical processes behind the foods we eat can be harnessed to create a better understanding of our bodies’ processes and how to alleviate certain undesirable feelings.
Research is currently developing in Colorado State University. Published March of 2017, a group of chemists are trying to find ways to create simple, handheld tests that may detect certain pathogens that may be hiding in food/water to avoid food poisoning cases. Food poisoning is usually caused by a bacteria called FIB which are the most dangerous type of pathogen to get with food poisoning (is the cause of the most cases of hospitalization). Before now, the most common methods of detecting food poisoning have been immunoassays and polymerase chain reactions (PCR). These methods may work moderately well, but they also have the unfortunate tendency towards false positives and also require expensive equipment. The research focuses on creating less expensive, more accurate ways of detection to aid the future of medical treatments of severe food poisoning. The first test that they created is a small strip of paper treated with a substrate molecule that changes color when it contacts the bacterial enzyme. It’s almost like a litmus paper used to test pH. The second test they developed is electrochemical and consists of screen-printed carbon electrodes on transparent sheets, which indicate the same bacteria by being inserted into a reader. These tests would not be as specific in detecting the exact bacteria that is causing the food poisoning, but it would be faster and give them the general idea.
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Pictures:
http://www.oneresult.com/sites/default/files/u3/Apple%20Browning.png
Anandi you post has taught me so much. I really shouldn’t be drinking water after eating really spicy foods, but instead I should be drinking milk. I do love to cook and this information is very helpful to me. I do enjoy eating apples and I was always so confused when I would let it sit for a minute and when I came back it was already turning brown. I am wondering though why is it that apples and avocados oxidize so fast?
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ReplyDeleteIt's always fun and interesting to read in-depth explanations for chemical processes that we take as simple just because we witness them often. Mixing simple descriptions of particle interaction and thermal chemistry with relatable examples of cooking and an intriguing topic, you have cooked up a very informative and readable post. Great job. (pun intended)
ReplyDeleteAs someone who cooks a lot, I thought this post was really interesting. Obviously the oxidation of things like fruits is something we've talked about this year, but by reading your post it is easier now to apply these facts to other elements of cooking involving the heating and cooling of foods. Additionally, I can see how the oxidation process would apply to advanced aging techniques such as the dry-aging of steak.
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