April 30, 2013

Cajun Cooking and Chemistry

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On April 9, three student teams combined Cajun cooking and chemistry in a national competition as part of the American Chemical Society’s New Orleans conference, which was themed “The Chemistry of Food and Energy.” The competition, titled “Communicating Chemistry: Cajun Cooking,” was organized by Prof. Gavin Sacks M.S. ’01 Ph.D. ’05, food science, and Prof. Justin Miller, chemistry, Hobart and William Smith Colleges.

The teams from California State University, Fresno, College of the Ozarks and Cornell University were selected as finalists out of a dozen of applications to compete at Dickie Brennan’s steakhouse in the French Quarter. The students’ task? To deliver a compelling, scientifically rigorous cooking demonstration that catered to the theme of Creole or Cajun cooking. Both Creole and Cajun cuisines originated in Louisiana and were heavily influenced by French recipes and techniques.

Participants were encouraged to develop their presentations as if they were on a food-related television show.

“We wanted the students to come up with at presentation that they could imagine someone watching television to be drawn in and stuck on their channel,” Sacks said.

The teams investigated and presented the chemistry that drives the flavors and textures of traditional Louisiana recipes.

“We intentionally didn’t give a lot of guidance for what the presentations were to look like, and students came from very different perspectives – 1 [group] did a cooking show, one was more of a documentary style, and the third approached it more like an experiment,” Sacks said.

First on the menu was Fresno State’s gumbo, a one-pot stew that usually includes seafood and vegetables with a base of roux, a thickener made by carefully heating flour and oil. The team applied biochemical principles to explain the gelatinization and caramelization that is responsible for the roux, often described as one of the of the “mother sauces” of French cooking.

Flour, one of the main ingredients of the roux, contains starch, long chains of sugars, and amino acids, the building blocks of proteins. Heating flour in oil causes the sugars to react with the amino acids, which results in browning – this famous cooking reaction is called the Maillard reaction. Manipulating the heating conditions changes the chemistry behind the roux, which includes many other caramelization reactions in addition to the Maillard browning process, leading to different aromas and colors.

The second course was provided by the team from College of the Ozarks, which also explored another classic Cajun roux-based dish – crawfish étouffée. In French, “étouffée” means “to smother,” which describes the method of cooking the meat covered with a thin layer of vegetables and sauce. The students explored the chemistry of the ingredients in étouffée, including compounds such as capsaicin which is responsible for the heat of peppers.

“They made a mock-up of a cooking show with a Southern host who was giving the audience instructions on how to make an étouffée, but would periodically cut away to other group members to explain the chemistry,” Sacks said.

Last up was dessert, provided by the Cornell team. The students explored the science behind making pecan pie with the perfect consistency.

“You want a gelatinous, rich, creamy, custard-like filling. You don’t want something weak and runny that drips off the plate, but you also don’t want something impossible to chew,” Sacks said.

The pie filling is a gel – a solid dispersed in a liquid – which, in the case of pecan pie, is made from combining eggs and corn syrup. The secret to achieving that creamy pecan filling lies in the role that protein and metal ions, both present in egg yolks, play in stabilizing the gel. To demonstrate the importance of these key components, the Cornell team made a host of pecan pies by adapting the original recipe to include all egg whites, all egg yolks, gelatin, and other egg substitutes.

The students performed their demonstrations for a group of 100 attendees and also provided samples to the audience members. After evaluating the chemistry and the clarity of the presentations, the judges, a panel of food science experts including Shirley Corriher, Harold McGee, Darin Nesbit, and Prof. Terry Acree, food science, declared the contest a three-way tie.

Sacks said that he and Miller are looking ahead to future American Chemical Society conferences, where the locations would lend themselves well to a study of the local cuisine. The August 2014 meeting is scheduled to be San Francisco: the home of Ghirardelli chocolate and a large wine-producing region.

Original Author: Jacqueline Carozza