Even if you’re not watching your cholesterol, there are plenty of reasons to avoid eating eggs. Ethical issues aside, industrial eggs provide only about 20% of the energy it takes to produce them. And while some egg substitutes do exist, they often pale in comparison to the real thing. Josh Tetrick, the CEO of Hampton Creek Foods, thinks we can do better. Read more
With the Science of Pie coming up in just a few weeks, we’ve been spending a lot of time thinking about baked goods. And one ingredient in particular has really captured our imagination—the egg! In the realm of baked goods, eggs are highly revered for their binding and leavening abilities. The fats and proteins within an egg can also contribute to important properties like moisture, texture, and mouthfeel [1]. Read more
Two weeks from now, renowned Brazilian chef Alex Atala will be joining Science & Food for the first 2013 public lecture at UCLA. Chef Atala has generated a lot of buzz in the food world by discovering and classifying new ingredients from the Amazon basin. But Atala isn’t the only one looking to the South American rain forest for inspiration. By studying the fruit of the tropical plant Margaritaria nobilis (commonly known as the bastard hogberry), a team of researchers led by Dr. Mathias Kolle has created an amazing new material that changes color as it stretches. Read more
The 2013 Science & Food lineup is here!
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While waiting for the lectures, you can satisfy your science and food cravings by watching last year’s lectures and browsing our blog archives. Over the next couple of months, we will feature exciting new content here on the blog, including chef profiles, recipes, and contests. Don’t miss out! Follow us on Twitter, Facebook, and Tumblr to get all the latest Science & Food news.
We can’t wait to see you at the 2013 Science & Food lectures!
Primitive X Modern: Cultural Interpretations of Flavors
Featuring Chef Alex Atala
Wednesday, April 17 @ 7:00pm
Moore Hall 100 (map)
Chef Atala will discuss his approach to food and how his cooking has been impacted by science. Atala is renowned for pioneering regional cuisine using indigenous Brazilian ingredients and works closely with anthropologists and scientists to discover and classify new foods from the Amazonian region.
Edible Education
Featuring Chef Alice Waters, Dr. Wendy Slusser, and Chef David Binkle
Thursday, April 25 @ 7:00pm
Royce Hall Auditorium (map)
Chef Alice Waters will be joined by Professor Wendy Slusser and Chef David Binkle to provide and informative discussion on initiating change in how we eat through school lunches, edible gardens, and healthy campuses.
The Science of Pie
Featuring Chef Christina Tosi and Chef Zoe Nathan
Sunday, May 19 @ 2:00pm
Covel Commons Grand Horizon Room (map)
Chefs Christina Tosi and Zoe Nathan will share their perspectives on inventing desserts, with a particular emphasis on pie. Here, the students of the Science & Food undergraduate course will present results from their final projects, including live taste tests of apple pies. Final projects will be judged by a panel of esteemed local chefs, scientists, and food critics including Christina Tosi, Zoe Nathan, Jonathan Gold, and UCLA Professors Andrea Kasko and Sally Krasne.
Physicist Albert-László Barabási likes making connections. By studying networks, Barabási and his Northeastern University research group improve our understanding of everything from the internet to human disease.
Now Barabási and colleagues are using networks to learn more about the way we eat. In a paper published in Scientific Reports, Barabási’s research team posed the question:
“Are there any quantifiable and reproducible principles behind our choice of certain ingredient combinations and avoidance of others?”
In particular, the researchers call the food pairing hypothesis into question. First imagined in 1992 by chefs Heston Blumenthal and François Benzi, the food pairing hypothesis states that ingredients will work well together in a dish if they share similar flavors. Following this logic, chefs have come up with crazy new food combinations like Blumenthal’s infamous concoction of white chocolate and caviar.
Thanks to the efforts of food scientists around the world, we now have extensive information available about the many chemical compounds responsible for giving different foods their distinctive smells and tastes. Armed with this information, Barabási’s team created the flavor network, a giant web of ingredients linked by their shared flavor compounds.
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| The backbone of the flavor network. Each node represents a different ingredient, where the size of the node represents the ingredient’s prevalence in a variety of recipes. The thickness of a line between two nodes reflects the relative number of flavor compounds shared by the two ingredients. |
Just as the food pairing hypothesis would predict, the researchers found that North American and Western European cuisines indeed favor ingredient combinations with many shared flavor compounds. The researchers also found, however, that East Asian and Southern European cuisines tend to avoid pairing ingredients with shared flavor compounds. Soy sauce, scallions, and sesame oil, for example, share hardly any flavor compounds but are commonly combined in East Asian cuisine.
These unexpected findings fundamentally question our previous notion of flavor pairing. Although the food pairing hypothesis still holds for some cuisines, it appears there are many more desirable flavor combinations available than previously imagined. As researchers continue to examine a wider variety of ingredients and cuisines, we will be able to build even larger, more robust flavor networks to gain insight into the fundamental principles behind our ingredient pairing preferences.
Such flavor networks will also benefit the next generation of “creative” computers. By combining our current knowledge of flavor networks with computer learning, scientists at IBM are now creating adaptive computer systems that will “learn” to create desirable and innovative food combinations. One day, these computers could help create better school lunches or design menus that meet strict dietary restrictions without sacrificing great flavor.
Of course, there’s more to cooking than lists of flavor compounds and networks of ingredients. Factors like color and texture can have play equally important roles in the palatability of a dish. It therefore seems unlikely that a computer will ever be able to replace the creativity and aesthetic prowess of human chefs. But then again, did anyone expect a computer to win Jeopardy?
About the author: Liz Roth-Johnson is a Ph.D. candidate in Molecular Biology at UCLA. If she’s not in the lab, you can usually find her experimenting in the kitchen.
The next Science & Food lecture series is fast approaching, so stay tuned! Visit our website for more information and follow us on Twitter to get all the latest updates. Read more
The momofuku team, led by chef/owner David Chang, swung through town during our week on microbes. David Chang and Peter Meehan produce the literary magazine Lucky Peach. Dan Felder and Veronica Trevizo are chefs who work in the momofuku kitchen lab. For LA Weekly’s rundown of the public lecture, see here. For more photos, see here.
momofuku chef Dan Felder before class begins
Microbial fermentation is one of the oldest cooking techniques in the world. In the past two years, the momofuku team has been working to understand fermentation and apply it in innovative ways. When the team visited, we first tasted pistachio miso and MSG. Miso is traditionally made by inoculating soybeans or barley with Aspergillus oryzae, or koji in Japanese. Koji is a mold that is also used in making sake and soy sauce. The momofuku team took this idea a step further, experimenting with inoculating untraditional ingredients with A. oryzae. The resultant pistachio miso is a mildly salty paste with a subtle note of the nut. It tastes like dou fu ru, a fermented bean curd from China, of which, incidentally, some varieties are also made with A. oryzae.
The momofuku team took this pistachio miso another step further, by centrifuging it. The miso separated into 4 layers, one of which is the “pistachio tamari” pictured below. We also sampled cherry and rhubarb vinegars from the lab.
In making these fermentation products themselves, the momofuku chefs are putting an American spin on foreign products. Yes, they are Japanese in tradition, but they are made with a unique microbial community that is found nowhere else in the world except at 10th St and First Avenue in NYC. A deeper knowledge of science is valuable not only for understanding how each step of fermentation modifies the flavor and texture of the ingredients, it is also vital for safety. For a couple of years now, the chefs have been working with our friends Rachel Dutton and Ben Wolfe at Harvard who identify the microbes on momofuku samples and let the team know whether it is safe to eat them.
Further reading:
Felder, Dan, et al. “Defining microbial terroir: The use of native fungi for the study of traditional fermentative processes.” International Journal of Gastronomy and Food Science. 1.1 (2012): 64-69.
Speaking of letting things rot, see here to learn more about artist Heike Leis’ photographs of food rotting way beyond edibility.
In our unit on microbes and exponential growth, we learned about the role of microbes in altering flavor and mouthfeel. One of our favorite microbial foods is cheese: Cheese would just be spoiled milk if it were not for microbes.
To kick off the class, we challenged the students with a taste test featuring four distinct cheeses:
A) Amish Blue Wheel
B) Emmental
C) Cheddar
D) Port du Salut
We also presented four different types of microbes, and a bit about natural habitats. Can you guess which microbe belongs to which cheese? Answers below.
1) Propionibacterium (inhabit human skin)
2) Penicillium mold (grow in cool, moderate climate; some species have blue color)
3) Brevibacterium (grow especially well without much personal hygeine)
4) Lactococcus lactis (grow well in acidic conditions)
ANSWERS:
A. 2 – Blue cheeses are inoculated with a strain of Penicillium mold, Penicillium roqueforti. Needles or skewers are used during the inoculation, which is why blue cheeses often have distinct veins running through them.
B. 1 – Emmental is a type of Swiss cheese, which is known for its holes. These holes are bubbles excavated by carbon dioxide, a byproduct of lipid breakdown by Propionibacterium freudenreichii, subsp shermanii. Its close cousin, Propionibacterium acnes, is linked to acne.
C. 4 – Cheddar is an example of a wide variety of cheese types that rely on Lactococcus lactis for the first stage of ripening. L. lactis uses enzymes to produce energy from lactose, a sugar molecule common in dairy products. Lactic acid is the byproduct.
D. 3 – Port du Salut is a washed-rind cheese. The cheese surface is wiped or washed down with a brine that promotes the growth of certain bacteria in the air. A smear of bacteria can be directly applied to the surface to nudge along the process. Brevibacteria linens is commonly used during this inoculation. Ever get a whiff of stinky feet from your cheese? Brevibacteria linens is the culprit, in the cheese and on real smelly feet.
In our unit of pressure, we learned about the difference between a mealy and crisp fruit or vegetable. It turns out that bubble wrap is a good analogy.
From Smith et al (2003) Postharvest physiology and pathology of vegetables.
We already know that water inside the vacuole of a plant cell and the cell wall work together to keep the cell firm and rigid. When cells are full of water, a force, such as your bite, will puncture the cells and break open individual cells. That is when you experience the release of juices that accompany biting down on a crisp apple. On the other hand, sometimes the network of polysaccharides between cells becomes weak, and when force is applied, the cells separate from each rather than are cleanly punctured through. This is when we encounter the classic mealy apple. With time, the polysaccharide “glue” that binds cells to each other begin to degrade. The cells also begin to lose water. This is why apples that have been stored incorrectly for long periods of time often turn mealy.
Take bubble wrap as an analogy. When the bubbles in bubble wrap are sealed and full of air, it is very easy to get that satisfying “Pop!” when you puncture the bubble. However, when the bubbles are not fully inflated or have already been punctured, then it is much harder to pierce another hole in the same bubble.
Josiah Citrin visited class to discuss viscosity’s role in sauces and its effect on flavor and mouthfeel. Josiah is the chef/owner of Mélisse in Santa Monica and co-owner of Lemon Moon in West LA. 
Using the sauces that he brought for us to taste, Josiah traced out the evolution of sauce making from pre-1970s to present day. Traditional French sauces are sually thickened with a mixture of cooked butter and flour (roux). Consequently, they were thick and heavy on the palate. Then, in the 1970s, a shift towards more delicate preparations and sophisticated presentation took place. This nouvelle cuisine caused cooks to prepare sauces with less flour, relying more upon high quality butter, vinegar, and other less viscous liquids. In the 1990s and 2000s, the introduction into restaurant kitchens of techniques and ingredients previously only found in industrial food preparation saw the use of Ultratex 3, tapioca starch, xanthan gum, and other additives in sauce making.
A taste test of red wine sauce made 3 ways made this evolution particularly clear to us:
i. thickened with flour
ii. thickened with puréed shallots and butter
iii. thickened with Ultratex 3 (a tapioca-derived starch)
While the viscosities of the sauces were similar, the taste differences were quite striking. Each additive has its particular taste, and heat also creates new flavor molecules out of the base recipe.
A few of Josiah’s tips for sauce-making:
1) When making hollandaise, add salt at the beginning of preparation, before adding butter.
Why? Salt (NaCl) and water are both polar molecules, which means one part of the molecule is negatively charged while the other part is positively charged. Generally, like dissolves like, and water does dissolve salt very well. However, fat is nonpolar, and salt does not dissolve well in it. Thus, to make evenly salted hollandaise, make sure to salt while the sauce is still mostly water.
2) To make a very light and airy sauce, such as the mint cilantro cashew sauce, set with gelatin and foam with an iSi siphon.
Why? The iSi siphon produces a temporary foam consisting of air bubbles entrapped in a network of sauce molecules. However, the bubbles are unstable and will merge, causing the foam to quickly deflate. Introducing gelatin to the sauce, however, strengthens the network and extends the lifetime of the foam.
3) Need to keep sauces warm? Store them in thermoses instead of in open containers in water baths.
Why? Sauces stored in open containers will evaporate, and the flavor and mouthfeel will change due to the reduction of volume. Capped thermoses are perfect at trapping heat and also preventing evaporation.