Aroma and Flavor: How They Come to Be

We went to Cornell University College of Agriculture and Life Sciences New York State Agriculture Experiment Station (Ag Station). Here we met up with Dr. Gavin Sacks, an Assistant Professor of Enology and Food Science. He gave us a tour of the Ag Station, explaining in large what they did there, which was anything from helping individuals produce a food product on a larger scale so they could sell it to grocers, to determining how much poop was on our food.

Some of the products that the Ag Station helped make

The Ag Station is able to have a distiller because they have a license for it otherwise it’s illegal

Gavin took us to the room where individuals can make their own wine, or distill their own spirits. There were two types of tubs that were meant for fermenting the wine, some were for red wine, which ferments with the skins and seed and the other tubs were for white wine, which ferment without the skins and seeds.

After the crash course on how wine was made, Gavin took us to some of the research labs, which dealt with wine flavor and aromas. He showed us some machines that took fractions of compounds that would help better understand their function and what produces the aroma and flavor of wine. Which brought us to Dr. Terry Acree a Professor in Olfaction Taste Flavor Perception.

The oflactometer is used to smell aromas in food

Dr. Acree showed us this machine called the olfactometer and he gave us a demo where he filled a small syringe with some espresso. The olfactometer would break down the espresso into fractions of compounds and send it through a tube that lead to the nose. Since I was writing the blog I was able to use the olfactometer. I sat down in front of it and the tube where the aromas came out was placed under my nose. I was told to take short quick breaths through the nose and out my mouth, and do it without hyperventilating, which I thought was rather difficult. The first aroma that hit my nose was a cracker like smell. There wasn’t much time to enjoy it though because as soon as it came out it stopped and five seconds later a new aroma came out. Some other aromas I smelled from the syringe of espresso were flowers, dirty socks, earthworm, garlic and sulfur. The coffee aroma did eventually come out, but I never expected all those other aromas to be present in espresso. The olfactometer allows Dr. Acree and his colleagues to identify aroma compounds that are in our food, they can then try and determine how these compounds originated. However, I’d imagine that it’s more fun to figure out how the flavor and aroma compounds came to be that are not expected to be in the food that we eat, such as dirty socks in the espresso.

This is where perception of taste is tested in individuals

The last place Gavin took us was to the taste testing room for wine. He explained that perception plays a big role on how people judge if wine is good or not. Therefore, the fancier the glass the wine is served in the better people think the wine is, even if it is not good wine. And the exact opposite can be said, a good wine, poured in a crummy cup is not going to be good to the consumer.

Just imagine for a second the smell of a rich chocolate bar. Your nose becomes engulfed in a smooth, sweet, creamy delectable fragrance, which makes you yearn for its source to become one with you. One would expect their original forms to mirror these same traits. However, the cocoa bean raw is nothing like the chocolate that we eat and enjoy today. The cocoa bean has a dark or light brown appearance, with a hint of a dark chocolate aroma, so naturally you expect it to taste similarly. This is not the case at all; the cocoa bean has a very dry chalky/earthy and bitter flavor, your expectations were completely crushed.

So how can you take the bland taste of a cocoa bean and turn it into the chocolate we enjoy so much? Fermentation of the bean is the first key step in acquiring chocolate. The fermentation produces acetic acid and ethanol, which inhibits germination and also produces structural changes in the flavor compounds. However, both over and under fermentation will lead to undesirable chocolate traits, so according to the study conducted by “Afoakwa, Emmanuel Ohene,

Flowchart on making chocolate

Paterson, Alistair, Fowler, Mark and Ryan, Angela(2008) ‘Flavor Formation and Character in Cocoa and Chocolate: A Critical Review’, Critical Reviews in Food Science and Nutrition, 48: 9, 840 — 857”, reaching a pH of 5.20-5.49 gives the ultimate chocolate sensations. After fermentation the beans are then dried, which further oxidizes the compounds creating new flavor compounds. The roasting is a huge component in forming flavor compounds. Roasting is a type of Maillard reaction, which is a browning reaction, and through Strecker Degradations and Amadori Rearrangements these new compounds are achieved. After the beans have been roasted they are ground and refined creating a dark thick paste like fluid called cocoa liquor. The cocoa liquor is then pressed, separating it into cocoa powder and cocoa butter. Then in a process known as conching, which takes pure cocoa liquor and adds sugar, milk solids, vanilla exact, a few other ingredients and finally cocoa butter. By mixing all of these ingredients together for a while, we ultimately obtain the chocolate that we love so much.


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