It’s two weeks after spring break and it is time to get back to work. This week in the chemistry of food, we are talking about corn and all of its complexity. At the beginning of class we defined exactly what kinds of corn there are. This definition was necessary because there is some corn, though on the cob, that we as humans do not eat during our summer cook-outs. Basically, there are two kinds of corn: sweet corn and Number 2 Commodity corn.
Sweet corn is the kind of corn we can eat. This is the kind of corn you buy at the store on the cob or in the can, and cook for dinner Sunday nights. Number 2 commodity corn, however, has a less direct application in our diet. This is the kind of corn with which companies make high fructose corn syrup (HFCS), and what the meat industry uses for feeding their cattle. From this definition launched a discussion about the different parts of a cob of corn and finished with the chemistry of making HFCS.
When you break it down, a cob of corn is made up of about 4 parts. You have the base cob, of course, the skin of the kernel (which is a carotenoid), the germ (which contains the proteins and oils), and the endosperm (which contains the starches and carbohydrates).
Most of these parts are fairly straightforward; however the starches have a couple of different uses. The first is that xanthan gum is made from the starch of the corn kernel. Xanthan gum is a compound that is used as a stabilization substitute for gluten free breads, as well as other products that could use some extra stability. The second is that the starch from the endosperm of the corn can be used to make HFCS.
If you take the starch from the endosperm and treat it with acid, you will eventually get glucose. By treating that synthesized glucose with glucose isomerase, the resulting product is HFCS.
Another added use of the starch from corn is if you ferment it, you will eventually produce ethanol. This is an important tip for corn farmers as it allows them to expand their market beyond the food industry. They made a deal with the gas and oil companies that now, all gas must contain around 10% ethanol in their mix, which is a very useful trick for the corn industry. The history behind this deal is simple: the government is already involved in the corn industry. Corn is a subsidized product, meaning that the government is paying the farmers by the bushel of corn they grow, for that corn. As a result, the government can make a law requiring that all gas must contain a percentage of ethanol. Hence the deal between these seemingly unrelated industries.
The other main chemical point we discussed was the Haber-Bosch process. Essentially this is the process by which artificial fertilizers were made. You may find yourself asking, “How can a fertilizer be artificial, isn’t it just manure?”. Well, what these German scientists found was that if you add 1 mol of N2 to 3 mols of H2 with an added catalyst of ruthenium and run this reaction under a lot of heat (created by fossil fuels) and a lot of pressure, you can synthetically make ammonia. If you oxidize that product you will eventually get nitric acid. By adding in some more NH3, you will create ammonium nitrate (NH4NO3) which is what can be marketed as artificial fertilizer. This can essentially eliminate the need of using manure or having a source of the wonderfully smelly stuff around to use as fertilizer. It also makes things easier for farmers (such as corn farmers) to purchase and fertilize their massive farms effectively.
So, in a nut shell, corn is not such a simple product. It can be manipulated and changed into completely different products and can make its way into our industry in many different ways. You can also see that normally natural processes have been found to be accomplished synthetically and learned the process by which this is done.