Archives for category: cooking

This changed the way I look at beer. More specifically, this is what I saw in the sediment at the bottom of various beers with a 60x optical microscope. I think I like this fermented beverage even more now.

Harpoon UFO

Harpoon UFO (60x)

Lambic Beer

Lambic Beer (60x)

Hefeweizen

Hefeweizen (60x)

I’ve been spending the week looking at microbes in food: http://www.msi.harvard.edu/graduates/microscopy.html. I think all my favorite foods and drinks (natto, yogurt, tempeh, beer, wine, chocolate, coffee, bread, cheese, kefir, kimchee, sauerkraut, nutritional yeast, mushrooms…) have some bacteria, fungi, or yeast involved.

Cooking: The Exhibition

coming soon....

One area of food science that I find quite interesting is how to reverse engineer traditional dishes with unconventional ingredients. One example is the dairy-free Dulce de Leche ice cream from Turtle Mountain:

INGREDIENTS:FILTERED WATER, ORGANIC SOYMILK (FILTERED WATER, ORGANIC SOYBEANS), ORGANIC DEHYDRATED CANE JUICE, CARAMEL SAUCE (TAPIOCA SYRUP, WATER, MOLASSES, SOY PROTEIN, NATURAL FLAVOR, COCOA BUTTER, SODIUM CITRATE, SALT, CARRAGEENAN), ORGANIC TAPIOCA SYRUP AND/OR ORGANIC BROWN RICE SYRUP, ORGANIC SOYBEAN OIL AND/OR ORGANIC SAFFLOWER OIL, CHICORY ROOT EXTRACT, CAROB BEAN GUM, GUAR GUM, ALGIN (KELP EXTRACT), CARRAGEENAN, YUCCA EXTRACT, TAPIOCA SUGAR, SEA SALT, NATURAL FLAVOR.

It’s a whole syllabus of food science in an ingredient list. Here are my best guesses:

  • To replicate the browning reactions of milk, they use tapioca syrup and carrageenan for the viscosity, cocoa butter for the melting behavior, and sodium citrate for the slight acidity.
  • The soybean and safflower oils provide fat, but the chicory root extract, carrageenan, algin, and gums are needed to stabilize the emulsion.
  • Yucca extract could be a saponin (soap-forming molecule), which is also used in root beer.

Another example is Babycake in New York City. Here is the ingredients list for the chocolate cupcake recipe (full recipe available here):

  • 1 cup garbanzo and fava bean flour
  • 1/4 cup potato starch
  • 2 tablespoons arrowroot
  • 1/2 cup cocoa powder
  • 2 teaspoons baking powder
  • 1/4 teaspoon baking soda
  • 1/4 teaspoon xanthan gum
  • 1 teaspoon salt
  • 1/2 cup coconut oil
  • 2/3 cup agave nectar
  • 6 tablespoons applesauce
  • 2 tablespoons vanilla extract
  • 1/2 cup hot water or hot coffee

I’m intrigued by the mixture of polysaccharides (chickpea and fava bean flour, potato starch, arrowroot, and xanthan gum) and the flours also have a considerable protein and fat content. I haven’t been able to find more quantitative information yet, but I would like to compare this to regular pastry flour. The coconut oil is high in saturated fats, so its melting range would be similar to butter. The pectin in the applesauce could help stabilize the batter. I’m not sure about the role of the baking soda.

Yet another example is vegan meringues. Here’s the ingredient list from Angel Food:

Ingredients: rice starch, emulsifiers 475 and 471, tapioca starch, methylcellulose, xanthan gum. All ingredients are plant-derived.

Emulsifier 475 is a “polyglycerol ester of fatty acid” and E471 is some type of salt of a fatty acid (thanks Food Additives).

2,000 calories/day: we’re all 100 watt light bulbs with the orthodox nutritional advice. The more I read more about metabolism, the more ludicrous it seems.

  1. Change in energy stores = energy input – energy output. This equation has to be balanced, although it implies no causality. An increase in energy input (i.e. eating more) could cause a person to increase his energy output (i.e. higher metabolic rate), etc.
  2. Overweight people overeat. This is about as profound as saying that alcoholics drink too much. Daily caloric intake between two adults can vary by a factor of five (e.g. people on caloric restriction diets vs. ultramarathon runners), yet their weights can be stable.
  3. Twenty-seven hundred calories per day is a million calories per day. Over two decades that’s 25 tons of food. It’s actually amazing that humans can maintain such a relatively stable weight for so long.

After reading “Good  Calories, Bad Calories” by Gary Taubes, listening to the Cooking Issues podcast, looking through “What I Eat” by Peter Menzel and Faith D’Aluisio, and watching “No Reservations” with Anthony Bourdain, as well as tracking my own diet with MyPlate, I’ve broken down a lot of assumptions that I made in the past.

One of the best things about my job is serendipity. Having an inconveniently located office that is often way too hot or too cold means that I’m walking around a lot. In the past couple days, stopping to chat with people in the hallway has led to new ideas for: scheduling equipment on the lab’s website, studying the textures of cooked meats with an electron microscope, a molten chocolate cake lab to teach heat transfer to grad students, using microfluidics to study emulsions, studying sourdough bacterial growth with a new microscopy technique, and more.

This morning I worked on developing a lesson plan for the ENGAGE program, to integrate everyday examples of engineering into undergraduate curricula and persuade more students to stay in related disciplines. I picked sous vide cooking, since it incorporates to many different aspects of both science and cooking:

  1. Engineering: an immersion circulator uses negative feedback to maintain the temperature of the water bath. How could this equipment be made more accessible to home cooks?
  2. Biochemical: the proteins or starches in the food denature at specific temperatures. Is it possible to qualitatively understand differences in these temperatures by looking at the amino acid sequences and protein sizes.
  3. Mathematical: the heat diffusion into the food can be modelled by diffusion equations. How well do these match up with values in recipes and why might there be discrepancies?
  4. Microbiological: microbial growth rates are relevant when developing safe food handling procedures. How does the temperature affect the doubling times of different  species?
  5. Culinary: in addition to precise control over texture, the method makes preparing fish, meats, and eggs potentially far more convenient (e.g. no need to soft boil eggs during service). How does a restaurant optimize the use of the water baths, if different foods require different temperatures?

I think that a similarly broad set of questions can come from looking at a single nutritional label, investigating the numerous roles of eggs in cooking, or all the steps involved in making chocolate.