Photo credit: Flickr user cmbellman

Photo credit: Anders Adermark (cmbellman/Flickr)

Fizzy, bitter, yeasty, sour, floral, and sometimes just downright offensive—there are a dazzling array of adjectives that can come to mind when you think of fermentation. Fermentation is one of world’s oldest and simplest culinary traditions. Serendipitously discovered in ancient times as a means of preservation, flavor enhancement, and intoxication, it has exploded as an art and scientific field in recent years. Aptly described by Chef David Chang as when “rotten goes right,” fermentation is a process that harnesses the power of benign microbes to produce complex flavors and can transform a seemingly rotten pile of vegetables into a curiously palatable delight (1). It’s fermentation we can thank for transforming a lonely, simple cabbage into a bustling hotspot for microbial activity that we know as sauerkraut.

German for “sour cabbage,” sauerkraut is distinctively tangy, floral, and surprisingly simple to create. It requires no specialized ingredients or starters, demanding just cabbage and salt (1). Sauerkraut is an example of wild fermentation, a process that exploits microbes native to the surface of cabbages. To make a batch, begin with finely shredded cabbage with roughly 3 tbsp salt per 5 lbs of cabbage. Give your fingers a workout by gently massaging the cabbage mix and after a few minutes, you’ll notice that the cabbage appears to be sweating (2). This sweat is the basis for our brine, whose presence is absolutely vital in our cabbage-to-sauerkraut transformation.

This brine sets a stage for successful sauerkraut fermentation, a fermentation made possible by the flavorful collaboration between several different microbes. These microbes, specifically lactic acid bacteria and yeast, thrive in salty, anaerobic environments, much like in the brine (1). Although the brine is simple, comprising just salt and water, it must be carefully controlled so as to provide the lactic acid bacteria and yeasts with a competitive advantage over other undesirable organisms. Too much salt and you ruin the palatability of our sauerkraut, but too little salt and you risk creating an environment favorable to spoilage or pathogenic bacteria (3).

As the microbes feed on sugars in cabbage, they mainly produce lactic acid, which like salt lends taste in addition to antimicrobial effects. As the brine becomes enriched with lactic acid, the pH declines and the sauerkraut begins to develop tart notes. These effects inhibit the growth of our unwanted microbes, which tend to be sensitive to acidity. Secondary products can also include carbon dioxide, alcohol, and acetic acid, all of which can suppress the growth of our unwanted organisms, too (3).

After massaging long enough, you should have enough brine to prepare your cabbage for jarring. Employing a willing and eager fist, pack your cabbage into a jar so that it’s completely submerged beneath the recently-created brine—you may also want to consider weighing it down. Ensure that your cabbage is entirely covered by brine, otherwise you risk inviting the growth of harmful aerobic bacteria into your jar. Anything left exposed to air is susceptible to mold or invasion of other organisms (2).

Depending on your preferences, you can let your sauerkraut ferment for just a few days or up to several weeks if you prefer stronger flavors. Leave it in a closet, on your countertop, or bury it in your backyard—it’s totally up to you!

References cited

  1. McGee, Harold. On food and cooking: the science and lore of the kitchen. New York: Scribner, 2004. Print.
  2. Katz, Sandor E. Wild Fermentation: The Flavor, Nutrition, and Craft of Live-Culture Foods. White River Junction, VT: Chelsea Green Pub, 2003. Print.
  3. Katz, Sandor E., Michael Pollan. The Art of Fermentation: An In-Depth Exploration of Essential Concepts and Processes from Around the World. White River Junction, VT: Chelsea Green Pub, 2012. Print.

Mai NguyenAbout the author: Mai Nguyen is an aspiring food scientist who received her B.S. in biochemistry from the University of Virginia. She hopes to soon escape the bench in pursuit of a more creative and fulfilling career.

Read more by Mai Nguyen

Gutopia: A Microbial Paradise

The development of the microscope in the 17th century magnified our awareness of a microbial universe previously invisible to the naked eye. Anton van Leeuwenhoek, a Dutch textile draper and science hobbyist, was one of the first individuals to glance into the microbial looking glass and identify unicellular organisms (so-called animalcules) such as protozoa and bacteria [1]. His colleague, Robert Hooke, went on to publish the seminal text, Micrographia, which described his observations of microfungi [2]. Two centuries later, Louis Pasteur validated the role of microbes in fermentation. However, Pasteur also gave weight to Ignaz Semmelweis’ controversial germ theory of disease stating that microbes have the capacity to cause pathological effects on our human health [3].


Early microbial drawings by Anton Van Leeuwenhoek [Photo Credit: Yale University Press]

These early studies in microbiology have provided significant insight on the human-microbe interaction characterized by either mutually beneficial or lethal outcomes. The duality of microbial behavior has dramatically impacted our perception of these microorganisms. Our cultural germophobia often precludes our ability to recognize the naturally transformative and symbiotic properties of microbes from the fermentation of grape juice into wine to their invaluable role in human digestion.

Michael Pollan, author of Cooked, explores a myriad of cooking traditions including those that directly involve the action of microbes such as bacteria and yeast. In his depiction of ancient sourdough recipes, he lists four ingredients: whole grain flour, water, salt, and the repertoire of microbes in the air [4]. The microbes catalyze slow-fermentation reactions (taking up to 24 hours) that leaven the bread while transforming molecules into digestible nutrients for us to absorb.

Whether we can stomach it or not, we all possess unique microbial signatures that are composed of trillions of microorganisms living both inside our bodies and on the surface of our skin [5]. These microbial communities, referred to as the human microbiome, cohabitate in our various mucosal, gastrointestinal, and epidermal surfaces. Symbiotic microbes are tolerated by our immune system and work collaboratively with our own bodies to digest the foods that we eat at the molecular level.

Our evolutionary history with bacteria is fueled by the currency of nutrition. In other words, our diet has a significant impact on the composition of our gut microbiota. Food consumption habits can either encourage the intestinal bloom of beneficial bacteria or opportunistic, disease-causing bacteria. Certain foods contain vital prebiotic molecules that encourage the expansion of beneficial bacterial species in the gut. High fiber foods including whole grains (brown rice, oats), vegetables (broccoli, peas) and legumes (lentils, black beans) contain an invaluable source of metabolic substrates that are converted into short-chain fatty acids by bacteria [6]. These short-chain fatty acids, such as butyrate, help to propagate microflora such as Bifidobacterium and Lactobacillus and maintain gastrointestinal tissue health [7].

If we were to design a perfect microbial habitat–a Gutopia, if you will, it would be a homeostatic organ city of diverse symbiotic microbiota that is rich in fiber economy and free of any harmful pollutants. However, our dietary choices can tip the balance of this intestinal paradise and create a dystopic environment suitable for the expansion of pathogenic microbes.

Contemporary eating habits that are characteristically high in fat and carbohydrates are responsible for the emergence of modern diseases such as diabetes, colorectal cancer, and inflammatory bowel diseases [8-11]. Recent studies suggest that compositional changes in the intestinal microbiome can encourage the bloom of disease-causing microflora. The dramatic alteration of today’s eating behavior introduces gastrointestinal disturbances or challenges that our bodies and microbial counterparts have not evolved to accommodate. For example, a study investigating the consumption of different dietary fats in immunocompromised IL-10/ mice identified the expansion of B. wadsworthia; a gram-negative, sulfur-reducing species of bacteria flourished in mice fed a diet high in saturated fat , but not in low-fat or polyunsaturated fat diets [12-13]. The bloom of B. wadsworthia was attributed to the unregulated production of a bile salt known as taurocholic acid brought about by the overconsumption of saturated fat.


Imbalanced dietary intake and overconsumption of foods high in saturated fats can impact the ecology of gut microbiota [Illustration by Grace Danico]

Taurocholic acid is an important source of sulfur that can stimulate the growth and maintenance of the pathogenic B. wadsworthia in these mice. The presence of this bacterium activates murine proinflammatory immune defense mechanisms that compromise the permeability of gut mucosal tissue causing intestinal inflammation. This pathogenic etiology of gut inflammation is implicated in the onset of Crohn’s disease and ulcerative colitis [12-13].

Much like any city there are complications that arise, which can tip the balance between utopic and dystopic environments. In the case of our gut health, we should imagine ourselves as landscape architects cultivating the balanced ecology of our microbiome. If we feed our intestinal gardens with the right balance of foods we can foster the growth of symbiotic bacteria while discouraging the bloom of pestilent, pathogenic microbial weeds.

The human microbiome not only affects our gut health but can have some profound effects on our behavior and brain function. Dr. Elaine Hsiao, Assistant Professor in the Department of Integrative Biology and Physiology at UCLA, investigates the interplay between our commensal microbes and their role in neurological development and function. Her work has linked the perturbations in gut microbiota with the onset of neurological disorders such as autism [14].

As we continue to study the ecology and diversity of microbes living within and around us, we are faced with many fundamental challenges in testing the dynamics of these microbial communities. From a clinical perspective, physicians and researchers alike have utilized human fecal samples to identify unique microbial gut profiles in their patients. These samples serve as powerful investigative tools in our pursuit to understand how certain commensal microbes can cause or serve as diagnostic readouts. The power of the sequencing technology used to characterize microbes in stool samples (16s RNA sequencing) comes from its level of coverage-the ability to identify the majority of bacteria in a sample. However, sequencing depth-the resolution at which a species can be identified remains challenging. Additionally, many microbial species have been challenging to culture in vitro, making it difficult for researchers to repeatedly perform experiments in a laboratory setting and gain a deeper mechanistic understanding of microbial behavior and ecology.

Dr. Rachel Dutton, Assistant Professor in the Division of Biological Sciences at UCSD, addresses some of these technological limitations by studying the establishment and maintenance of microbial communities in different types of cheeses. With this model, her lab can investigate the interactions of different types of microbes to better understand them as ecological systems [15-16].

Science & Food is honored to host Elaine Hsiao and Rachel Dutton for the 2016 UCLA Science & Food public lecture series to elaborate on their findings.  They will be accompanied by Sander Katz, author of Wild Fermentation, who will discuss the transformative properties of microbes in the production of foods like sauerkraut.

Join us on Wednesday, May 11th at 7PM in Schoenberg Hall at UCLA for “Microbes: From Your Food to Your Brain” to learn more about the intriguing world of microbes!

References cited

  1. Gest H. “The discovery of microorganisms by Robert Hooke and Antoni Van Leeuwenhoek, fellows of the Royal Society”. Notes Rec R Soc Lond. 5 (2004). 187-201.
  2. Hooke R. “Micrographia” Jo. Martyn & Ja. Allestry (1665).
  3. “The History of the Germ Theory” The British Medical Journal. 1 (1888).
  4. Pollan M. Cooked: A Natural History of Transformation. Penguin Books. (2013).
  5. Abbott A. “Scientist bust myth that our bodies have more bacteria than human cellsNature. (2016).
  6. Leone V, Chang EB, Devkota SD. “Diet, microbes, and host genetics: the perfect storm in inflammatory bowel disease” J. Gastroenterol 48 (2013). 315-321.
  7. Sartor RB,.“Microbial influences in inflammatory bowel disease: role in pathogenesis and clinical implications” Elsevier (2004). 138-162.
  8. Hotamisligil, GS. “Inflammation and metabolic disorders” Nature. 444 (2006). 860-867.
  9. Parkin DM, Bray F, Ferlay J, et al. “Global cancer statistics” CA Cancer J Clin. 55. (2005). 74-108.
  10. Loftus EV Jr. “Clinical epidemiology of inflammatory bowel disease: incidence, prevalence, and environmental influences” Gastroenterology 126. (2004). 1504-1517.
  11. Molodecky NA, Soon IS, Rabi EM, et al. “Increasing incidence and prevalence of the inflammatory bowel diseases with time, based on systemic review” Gastroenterology 142. (2012). 46-54.
  12. Devkota SD, Wang Y, Musch MW, et al. “Dietary-fat-induced taurocholic acid promotes pathobiont expansion and colitis in Il10-/- mice” Nature. 487 (2012). 104-108.
  13. Devkota SD, Chang EB. “Diet-induced expansion of pathobionts in experimental colitis” Gut Microbes. 4:2 (2013). 172-174.
  14. Hsiao E.Y., “Gastrointestinal issues in autism spectrum disorder”, Harv Rev Psychiatry, 22 (2014). 104-111.
  15. Wolfe BE, Dutton RJ. “Fermented Foods as Experimentally Tractable Microbial Ecosystems” Cell. 161(1) (2015). 49-55.
  16. Wolfe BE, Button JE, Sanarelli M, Dutton RJ. “Cheese rind communities provide tractable systems for in situ and in vitro studies of microbial diversity” Cell. 158 (2014). 422-433.

Anthony MartinAbout the author: Anthony Martin received his Ph.D. in Genetic, Cellular and Molecular Biology at USC and is self-publishing a cookbook of his favorite Filipino dishes.

Read more by Anthony Martin

Titanium Dioxide in Food

Video & guest post by Carolyn Meyers & Edgar Rodriguez

Titanium dioxide isn’t something we usually request as a donut topping from the local bakery. However, most of the sweets we eat on a daily basis contain this chemical.

What is titanium dioxide?

Titanium dioxide has a solid tetragonal crystalline structure and is derived from three main natural minerals: rulite, anatase, and brookite.


Photo credit: Dambournet, D., Belharouak, I., Amine, K. Chem Mat, 2009, 22, 1173-1179.

Where does titanium dioxide come from?

U.S. Companies, such as DuPont, Cristal Global, Louisiana Pigment Co. L.P., and Tronox Ltd. process the mineral into a white powder, which has a refractive index of 2.5837, making it ideal for use as a filler or pigment that adds opacity to things like sunblock, shampoo, chewing gum, chocolate, and powdered donuts. Production of pure titanium dioxide is achieved through a method called the chloride process, wherein the raw minerals are first reduced with carbon and then oxidized with chlorine. Liquid titanium chloride (TiCl4) is then distilled and converted back into titanium dioxide by heating it to high temperatures in a pure oxygen flame.


Photo credit: GreenMedInfo

Titanium dioxide nanoparticles (TiO2) are widely used as a food additive and are consumed by millions of consumers on a daily basis, as manufactures incorporate it into their food products. TiO2 nanoparticles are used as an additive mainly to prevent UV light from penetrating the food, effectively increasing the shelf life. It is also used as a color enhancer to make foods appear white by enhancing the opacity.

How much TiO2 is in your food?

Many popular consumer products such as candies, gum, and baked goods contain 0.01 to 1 mg Ti per serving. The products with the highest titanium contents are sweets or candies [1]. For example, powdered donuts can contain up to 100 mg Ti per serving.


The amount of titanium found in certain popular consumer products. [1]

What are the health effects of ingesting titanium dioxide?

Titanium dioxide is marketed by DuPont as an inert chemical, meaning it shouldn’t react with other chemicals. Given the fact that powdered donuts include 100 mg per serving of titanium dioxide and the lethal dosage, measured as the LD50 or the amount needed for 50% of the population to perish from consuming the chemical, was measured in rats to be 5,000 mg/kg, A 200 lb human (90.7kg) would need to eat 4,535 powdered donuts and have a 50% chance of survival. (5000)X90.7= 453500 mg. Although it is impossible for a human to consume this many donuts at once, Dunkin Donuts recently stopped using titanium dioxide in their powdered sugar donuts after being pressured by the public to do so.

There have been numerous scientific studies done on how titanium dioxide affects the health. Many of these studies are performed using animal models, such as mice. Both positive and negative health effects have been found. One possibly positive health effect of ingesting titanium dioxide is a substantial increase in the levels of dopamine, the happiness hormone [2]. Negative health effects due to the ingestion of TiO2 nanoparticles include damage to the liver, kidneys, testes, brain and heart of mice and rats, as described below [3,4,5]:

  • Mice given doses as low as 50 mg/kg body weight experience hepatic damage in the form of: hepatic cell death, increased levels of reactive oxygen species, and altered antioxidant activity, as well as kidney damage [2,3,6].


    Photo credit: BabyMed

  • Oral exposure to Ti nanoparticles have been shown to produce significant negative effects in the brain such as major degenerative changes in the visual cotex and inflammation in the hippocampus [2, 7, 8, 9].


    Photo credit: UCSF News Center

  • Titanium dioxide particles have been shown to cross the blood-testis barrier in mammals, leading to reproductive toxicity in males, including a decrease in sperm motility percentage, sperm cell concentration, sperm viability and serum testosterone level, as well as a significant increase in sperm abnormalities [7, 10].


    Photo credit: WiseGeek

  • In humans, clinical research shows that patients with ulcerative colitis, a chronic inflammatory disease of the large intestine, have elevated levels of titanium in the blood and an accumulation of the chemical in the spleen [11].


    Photo credit: Turmeric for Health

Given this information, it remains the consumers’ responsibility, as always, to make an informed decision on the foods they eat and follow rules of moderation in everyday life.

References cited

  1. Weir, Alex, Paul Westerhoff, Lars Fabricius, Kiril Hristovski, and Natalie Von Goetz. “Titanium Dioxide Nanoparticles in Food and Personal Care Products.” Environmental Science & Technology Environ. Sci. Technol. 46.4 (2012): 2242-250. Web.
  2. Shrivastava R, Raza S, Yadav A, Kushwaha P, Flora SJS (2014) Effects of sub-acute exposure to TiO2, ZnO and Al2O3 nanopar- ticles on oxidative stress and histological changes in mouse liver and brain. Drug Chem Toxicol 37(3):336–347. doi:10.3109/ 01480545.2013.866134
  3. El-Sharkawy NI, Hamza SM, Abou-Zeid EH (2010) Toxic impact of titanium dioxide (TiO2) in male albino rats with special refer- ence to its effect on reproductive system. J Am Sci 6(11):865–872
  4. WangJ,ZhouG,ChenC,YuH,WangT,MaY,JiaG,GaoY,Li B, Sun J, Li Y, Jiao F, Zhao Y, Chai Z (2007) Acute toxicity and biodistribution of different sized titanium dioxide particles in mice after oral administration. Toxicol Lett 168(2):176–185. doi:10. 1016/j.toxlet.2006.12.001
  5. BuQ,YanG,DengP,PengF,LinH,XuY,CaoZ,ZhouT,XueA, Wang Y, Cen X, Zhao YL (2010) NMR-based metabonomic study of the sub-acute toxicity of titanium dioxide nanoparticles in rats after oral administration. Nanotechnol 21(12):125105. doi:10. 1088/0957-4484/21/12/125105
  6. Vasantharaja D, Ramalingam V, Aadinaath Reddy G (2015) Oral toxic exposure of titanium dioxide nanoparticles on serum bio- chemical changes in adult male Wistar rats. Nanomedicine J 2(1):46–53
  7. Elbastawisy YM, Saied HA (2013) Effects of exposure to titanium dioxide nanoparticles on albino rat visual cortex Belectron micro- scopic study. J Am Sci 9(5):432–439
  8. ZeY,ShengL,ZhaoX,HongJ,ZeX,YuX,PanX,LinA,Zhao Y, Zhang C, Zhou Q, Wang L, Hong F (induced hippocampal neuroinflammation in mice. PLoS ONE 9(3), e92230. doi:10.1371/journal.pone.0092230
  9. Mohammadipour A, Hosseini M, Fazel A, Haghir H, Rafatpanah H, Pourganji M, Ebrahimzadeh Bideskan A (2013) The effects of exposure to titanium dioxide nanoparticles during lactation period on learning and memory of rat offspring. Toxicol Ind Health. doi: 10.1177/0748233713498440
  10. Hong, F., Y. Wang, Y. Zhou, W. Zhang, Y. Ge, M. Chen, J. Hone, and L. Wang. “Exposure to TiO2 Nanoparticles Induces Immunological Dysfunction in Mouse Testitis.” PubMed. – Journal of Agricultural and Food Chemistry (ACS Publications), 13 Jan. 2016. Web. 22 Feb. 2016.
  11. Ruiz, PA, B. Moron, HM Becker, S. Lang, K. Atrott, MR Spalinger, M. Scharl, KA. Wojtal, A. Fishbeck-Terhalle, I. Frey-Wagner, M. Hausmann, T. Kraemer, and G. Rogler. “Titanium Dioxide Nanoparticles Exacerbate DSS-induced Colitis: Role of the NLRP3 Inflammasome.” PubMed. BJM, 4 Feb. 2016. Web.

Latte Science


Elsbeth SitesAbout the author: Elsbeth Sites received her B.S. in Biology at UCLA. Her addiction to the Food Network has developed into a love of learning about the science behind food.

Read more by Elsbeth Sites

Inside the Experimental Cuisine Collective


Robert Margolskee, Mitchell Davis, Florence Fabricant, Wylie Dufresne, and Hervé This at the Experimental Cuisine Collective’s launch workshop on April 11, 2007. Photo credit: Antoinette Bruno (Star Chefs)


Launched in 2007, the Experimental Cuisine Collective (ECC) has proven itself as an invaluable resource for those interested in learning about the scientific principles behind food. Founded by Drs. Kent Kirshenbaum and Amy Bentley of New York University in collaboration with Chef Will Goldfarb of WillPowder, the ECC hosts workshops approximately five times per year, each featuring different topics and/or speakers. ECC’s current Director is Anne McBride, a PhD candidate in Food Studies at NYU and Culinary Program/Editorial Director for the Culinary Institute of America. Widely recognized for her ability in establishing connections between scientists and chefs, McBride has been instrumental in developing ECC’s programs. ECC’s workshops have gained nationwide acclaim, featured in media outlets such as Serious Eats, New York Observer, and even the Food Network!

The impressive roster of past ECC speakers include renowned chefs and scientific minds such as Dan Barber, Wylie Dufresne, Rachel Dutton, and Mark Bomford. The topics of ECC workshops are also interestingly diverse, covering topics from soda politics with Marion Nestle to cooking insects with the Yale Sustainable Food Project to the New York Academy of Medicine’s Eating Through Time conference.

Our recent Science & Food public event featured Dr. Kent Kirshenbaum , who stopped to answer a few questions for us about the ECC:

What motivated you to start the Experimental Cuisine Collective?
I was asked by the National Science Foundation to consider establishing a science outreach program as part of their emphasis on “Broader Impacts” of scientific research. I’ve always been eager to establish connections between scientists and experts from other disciplines, so exploring the terrain between chemistry and cuisine came about very naturally.
What has been one of your most memorable experiences since founding the site?
The Experimental Cuisine Collective has always been more about direct engagement rather than as a web-based portal for information. One of my most memorable experiences with the ECC was preparing an alginate-based mango-juice pearl with a 4th grade student at a science fair.  I asked her if we were doing science or cooking. After a moment’s careful thought she replied, “I guess it’s both!” That was a very satisfying moment.

Another memorable experience was giving a lecture series about the ECC throughout New Zealand during the “International Year of Chemistry”. The director of the ECC, Anne McBride, and I got the chance to prepare what we believe were the world’s first vegan pavlovas for our audiences throughout New Zealand. We love Kiwis!

What do you hope the Experimental Cuisine Collective’s readers take away from the website?
I think they are excited about the lecture programs we are offering at NYU, and the opportunity to learn what science can contribute to cooking — along with how chefs can advance scientific objectives. Plus, I hope readers are quick to appreciate that we have been offering our programs for almost 10 years, and all of it has been completely free of charge!
Are there any upcoming projects you would like people to know about?
Our upcoming meeting will be devoted to hydroponic farming, in partnership with the Institute of Culinary Education. We will be meeting at ICE’s indoor 540-square-foot farm in lower Manhattan, designed by Boswyck Farms, which has 3,000 plant sites and in which 22 crops are currently growing. The amazing thing about this farm is that it is literally across the street from the tallest building in the Western Hemisphere. Science can help us grow in so many ways and places!

Ashton YoonAbout the author: Ashton Yoon received her B.S. in Environmental Science at UCLA and is currently pursuing a graduate degree in food science. Her favorite pastime is experimenting in the kitchen with new recipes and cooking techniques.

Read more by Ashton Yoon

Aquafaba & Other Hopes for Delicious Egg-free Meringues

Photo credit: (vegan-baking/Flickr)

Photo credit: (vegan-baking/Flickr)

Meringues are one of the few desserts that are simple yet elegant works of art. They are also precursors to other impressive, albeit considerably more complicated, desserts such as baked Alaska, lemon meringue pies, and macarons. At the bare minimum, all you need to make a fluffy meringue is egg whites, sugar, and an electric mixer—or an egg beater and some arm power. For vegans, this egg-containing dessert is not an option—but why should vegans (and those with egg allergies) miss out on this sweet, airy dollop of heaven?

To make a decent egg-free meringue, it helps to understand the meringue at the molecular level. How does a liquid get whipped into a cloud-like solid?

Egg whites, comprising 90% water, are undeniably runny. The other 10% consists of proteins, which play a major role in the fluid-to-fluff transformation. Mechanical stress from rigorously beating the egg whites causes the egg white proteins to denature, unfold from their natural structure. This exposes various amino acids, the building blocks of proteins, to the rapidly aerating environment. Some of the amino acids are hydrophobic (water-fearing), and some are hydrophilic (water-loving). As the egg whites are whipped, hydrogen bonds form between the hydrophilic amino acids and water in the egg whites. The hydrophobic amino acids prefer to be exposed to the air that is quickly beaten into the liquid mixture. Air ends up trapped in the meshwork of denatured proteins within the developing foam, and so the longer the mixture is beaten, the fluffier it gets. To retain the trapped air bubbles and generate peaks that stand up straight, sugar is added as a stabilizer. And eccola! Una nuvola dolce nella ciotola; a fluffy meringue is ready to bake or prepare into macarons or boccone dolce.

To create an equally amazing and delicious vegan counterpart, the egg whites would have to be substituted with an ingredient that has both water-loving and water-fearing parts. Logic may think to search for a plant-based protein alternative, but French chef Joël Roessel discovered that chickpea brine works perfectly well as a vegan egg-white substitute [1]. Coined aquafaba by Goose Wohlt (Latin for “bean water”), the leftover water from a can of chickpeas can be combined with sugar and whisked into a vegan meringue that surprisingly tastes nothing like beans. Of all the possible substitutions, why does aquafaba work in lieu of egg whites?

Photo credit: getselfsufficient/Flickr

Water leftover from cooking chickpeas, also known as aquafaba, can be used in lieu of egg whites. Photo credit: getselfsufficient/Flickr

Anne Rieder, a scientist at the Norwegian food research institute Nofima, analyzed aquafaba and revealed that the bean water contains equal amounts of proteins and carbohydrates [2]. The function of proteins in the aquafaba are similar for meringue-making; Rieber suggests that the carbohydrates may serve as an additional stabilizer by increasing the viscosity of the water portion of the foam.

To create foams like meringues, Kent Kirshenbaum, a professor at NYU, was inspired by chemistry to invent a foaming agent that is rich in saponins, currently awaiting patent approval. Saponins are a class of chemicals found in plants, including beans like chickpeas. The name derives from the soapwort plant, Saponaria, which contains the Latin root for soap, sapo; this is a fitting name, given the compound’s propensity to foam when shaken in water [3]. Like the amino acids of proteins, saponin molecules contain a hydrophobic and a hydrophilic moiety that enables them to interact with both air and water.

Whatever the reason for avoiding eggs, at least you won’t have to forfeit the heavenly delight that is a lightweight meringue cookie.

References cited

  1. Aquafaba history.” The Official Aquafaba Website.
  2. Aquafaba, what is its chemical composition?Frie kaker.
  3. Saponins.” Cornell University Department of Animal Sciences.

Alice PhungAbout the author: Alice Phung once had her sights set on an English degree, but eventually switched over to chemistry and hasn’t looked back since.

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From Field to Fork: Food Ethics for Everyone – An Excerpt


 “You are what you eat.”

This aphorism is consistently used to fit different scenarios, but are we really what we eat? Author Paul B. Thompson begs to differ. In his book, From Field to Fork: Food Ethics for Everyone, Thompson presents his case against this statement and brings light upon many ethical food dilemmas, including obesity, livestock welfare, and the environmental impact of food systems. He structures his thoughts around the idea that food ethics are being revived in the contemporary world. Regarding the aforementioned axiom, Thompson explains that food is more than just substance for your body’s functioning. Here is an excerpt analyzing this issue:

“On the one hand, dietetics has become a domain of personal vulnerability calling for regulatory action on moral grounds. What is vulnerable may be one’s health, as in the case of food safety or nutrition, but it may equally be one’s identity or solidarity with others as people attempt to achieve social justice and environmental goals through labels that promise ‘fair-trade’ or ‘humanely raised’ foods. On the other hand, practices that promote hospitable respect for personal dietary committees or solidarity may run afoul of a philosophy of risk that emphasizes classic hazards to health and physical safety. All told, it begins to look less and less like food choice can be confined to the prudential realm” (p. 29) [1].

In this passage, Thompson emphasizes that people may no longer be able to use good reason and judgment when choosing their food. The foods you choose to eat not only affect your body and health, but it also affects people and ideas around you. There is potentially harm being done on third parties connected to certain food purchases.

Thompson’s take on this statement is just one of the many issues he delves into in From Field to Fork. He offers deep philosophical and ethical analyses while integrating economics, history, science, psychology, and politics. For example, when discussing food systems, Thompson addresses multiple factors to consider when ensuring food sufficiency. Environmentally, a growth in monoculture production systems to mass-produce certain crops can tax natural resources. Socially, these industrial systems can destroy healthy rural communities. Politically, there are injustices that make it difficult to distribute these resources fairly. An extensive framework is given regarding how to approach food sufficiency and other issues in the book.

As a philosopher and current W. K. Kellogg Chair in Agricultural, Food and Community Ethics, Paul B. Thompson provides a comprehensive guide to food ethics in his book. From Field to Fork: Food Ethics for Everyone will not only give you a deeper insight into food, but also into our society.

References Cited:

  1. Thompson, P.B. (2015). From Field to Fork: Food Ethics for Everyone. New York, NY: Oxford University Press.


Catherine HuAbout the author: Catherine Hu received her B.S. in Psychobiology at UCLA. When she is not writing about food science, she enjoys exploring the city and can often be found enduring long wait times to try new mouthwatering dishes.

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Science & Food UCLA 2016 Public Lecture Series


The 2016 UCLA Science & Food public lecture series is here!

General admission tickets are available for $25 from the UCLA Central Ticket Office (CTO) . Tickets can be purchased from the UCLA CTO over the phone or in person and will not include additional fees or surcharges. The UCLA CTO is located on-campus and is open Monday–Friday, 10am –4pm. A UCLA CTO representative can be reached during these hours at 310-825-2101. Tickets can also be purchased online from Ticketmaster for $25 plus additional fees. A limited number of $5 student tickets are available to current UCLA students. These must be purchased in person at the UCLA CTO with a valid Bruin Card.


The Impact of What We Eat: From Science & Technology, to Eating Local
Chef Daniel Patterson, Dr. Paul B. Thompson, & Dr. Kent Kirshenbaum

Tuesday, March 8, 2016 at 7:00pm
Schoenberg Hall, UCLA



Microbes: From Your Food to Your Brain
Sandor Katz, Dr. Rachel Dutton, & Dr. Elaine Hsiao

Wednesday, May 11, 2016 at 7:00pm
Schoenberg Hall, UCLA



Curbing Carbon Emissions in Dining: A Conversation with Zero Foodprint
Chris Ying, Peter Freed, & Chef Anthony Myint

Thursday, May 19, 2016 at 7:00pm
Schoenberg Hall, UCLA

The Future of Food: The History of and Recent Advancement in Space Food


A typical meal in space in the eighties. Photo credit: NASA (UC Science Today)

When most of us think of space food, what comes to mind are probably those silver packets of freeze-dried ice cream you find in science center gift shops. Surprisingly, freeze-dried ice cream only made it to space once, on the Apollo 7 mission in 1968 [1]. Although at one time this may have resembled what astronauts actually ate in space, the development of space food has advanced light years since then (pun intended).


Food cubes and tubes from early Project Mercury (1953-63). Photo credit: NASA (

Space flights initially lasted mere minutes and were not long enough to necessitate consumption of a meal. However, as flight duration began to increase, scientists began to develop snacks for in-flight consumption. During NASA’s Project Mercury (1958-63), astronauts began to test what the physiology of eating, or how chewing, drinking, and swallowing function in space. The food was largely unappealing, mainly consisting of dehydrated cubes of solid food and semi-liquid mixtures in aluminum tubes. Technology improved when freeze-drying was introduced during Project Gemini (1961-66). Freeze-drying produced better taste, color, and texture, as well as maintained the integrity of food shape. To rehydrate the food, water guns were used to inject water into the freeze-dried packets [2].

The process of freeze-drying capitalizes on the chemical principle called “sublimation,” the phase shift from a solid to a gas, bypassing the liquid stage; as shown in the diagram below, this is achieved by specific ranges of pressure and temperature, depending on the substance [3]. Space food developers utilized this principle to turn the water in freeze-dried foods into vapor [2]. The freeze-drying process occurs in three stages: freezing, primary drying, and secondary drying. In the freezing stage, the product is cooled to below its eutectic point, or the lowest temperature at which the solid and liquid phase can coexist. In the primary drying phase, the pressure is lowered and just enough heat is applied to cause sublimation. The secondary drying phase removes any unfrozen water molecules [3].


Diagram of water phase behavior. Photo credit: Soham Shukla (IJPSR)

With the application of freeze-drying, space food development rapidly advanced. Hot water for rehydration and improved packaging both immensely improved the taste and efficiency of meals during Project Apollo (1969-72). Menus continued to grow and conveniences such as food warmers and dining tables further improved the gastronomic experience on flights during the Skylab and Space Shuttle programs (1973-79, 1981-2011) [2]. Today, the majority of what astronauts eat looks a great deal like what we eat here on Earth. Food and drinks are commonly powdered or freeze-dried, which simply requires the addition of water. Thermostabilizing is another common technique, which results in food or beverage products in pouches. Prior to every mission, astronauts attend a “tasting” of sorts where they select their meals and create their own personalized menu [1].

There are certain challenges that arise in space that must be overcome in space food. Food must be compact and lightweight as it currently costs a whopping $10,000 per pound to send food into space [4]. Packaging must efficiently deliver food without risk of spillage. Stray crumbs or liquids can float into equipment and cause massive damage, or be inhaled by astronauts [2]. Nutrition and preservation are also key factors as food must be able to keep for long periods of time while maintaining nutritional value. The diagram below shows how rapidly the numbers of acceptable thermostabilized foods decline within 5 years. All types of thermostabilized food products were analyzed, including vegetables, starches, fruits, desserts, and meats. The level of acceptability was determined by flavor as well as analysis of chemical reactions detected by colorimeter readings. Some products retain acceptability for a longer period than others. For example, meat was acceptable for 3 years or longer while some vegetables only lasted 1 year.

On long-duration flights, the nutritional value of foods is lost due to the oxidation of vitamins and fatty acids during long-term storage and radiation exposure [5]. This is of particular concern on lengthy missions, where bone density and vision can be negatively affected if the diet does not contain proper amounts of vitamin D and folate [6].


‘Shelf life’ of thermostabilized space foods. Photo credit: Cooper, Douglas, and Perchonok (Journal of Food Science)

Another problematic area involves the astronauts eating experience. In space, taste buds react differently and flavors are muted and more bland, almost like when you have a cold and cannot taste as vividly [7]. On early missions when space food was in its infancy, it was common for astronauts to lose their desire to eat, as the food was bland and difficult to prepare. Many ended up losing body weight, which in turn affected crew performance and the overall success of the missions [8]. Also very importantly, good quality food is linked to the well-being of astronauts. Dealing with homesickness, demanding physical missions, and an unknown environment all take a toll on the crew’s mental health. Providing tasty and familiar foods can improve quality of life on board [6].


Space “cheeseburger.” Photo credit: Terry Virts (Serious Eats)

The next step for space food? Mars. Food scientists are currently working to discover how to feed astronauts on a mission that would have a minimum 2.5 year duration (6 months to Mars, 18 month surface mission, and 6 month return journey to Earth). This will likely require that a portion of food be grown during the surface mission [9]. In August 2015, the first-ever crop grown in space, red lettuce, was ready for tasting! The lettuce was grown in the VEGGIE plant growth system on the International Space Station, a system composed of rooting “pillows” and LED light as solar replacement [10]. Will we eventually be able to grow foods and develop a safe and functional food system on Mars’ surface? With companies such as NASA and Elon Musk’s SpaceX looking to Mars as the next location for human tourism and eventual colonization [4], growing food in space will incontrovertibly become a requirement in the future.


Red romaine lettuce grown on the International Space Station. Photo credit: NASA (

References Cited

  1. Billock, J. “The Dark Side of the Spoon: What Astronauts Eat in Space.” Serious Eats. Serious Eats, 18 June 2015. Web. 19 January 2016.
  2. Casaburri, A.A., Gardner, C.A. “Space Food and Nutrition.” Educator’s Guide. NASA. Washington, D.C. 1999. Print.
  3. Shukla, S. Freeze Drying Process: A Review. International Journal of Pharmaceutical Sciences and Research, 2011; 12: 3061-68.
  4. Evans, J. Space Farming. C&I Agriculture, 2015; 10: 20-23.
  5. Zwart, S.R., Kloeris, V.L., Perchonok, M., Braby, L., Smith, S.M. Assessment of Nutrient Stability in Foods from the Space Food System After Long-Duration Spaceflight on the ISS. Journal of Food Science, 2009; 74: 209-17.
  6. Martin, B. “Unpack a Meal of Astronaut Space Food.” Smithsonian Magazine June 2013: Print.
  7. “Taste in Space.” NASA. NASA, 6 February 2015. Web. February 15 2016.
  8. Cooper, M.m Douglas, G., Perchonok, M. Developing the NASA Food System for Long-Duration Missions. Journal of Food Science, 2011; 76: 40-8.
  9. Lane, H.W., Bourland, C., Barrett, A., Heer, M., Smith, S.M. The Role of Nutritional Research in the Success of Human Space Flight. Advances in Nutrition, 2013; 4: 521-23.
  10. “Meals Ready to Eat: Expedition 44 Crew Members Sample Leafy Greens Grown on Space Station.” NASA. NASA, 7 August 2015. Web. 5 February 2016.

Ashton YoonAbout the author: Ashton Yoon received her B.S. in Environmental Science at UCLA and is currently pursuing a graduate degree in food science. Her favorite pastime is experimenting in the kitchen with new recipes and cooking techniques.

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The International Year of Pulses


Photo credits: (flickr/Jessica Spengler)

The 68th United Nations General Assembly has declared 2016 the International Year of Pulses. [1] Pulses – that throbbing sensation of your carotid artery after a workout or during a first date, right? Nope. The UN suggests we celebrate the pulses that are leguminous crops harvested solely for their dry seeds. All lentils, and all varieties of dried beans, such as kidney beans, lima beans, butter beans and broad beans are pulses, as are chick peas, cowpeas, black-eyed peas and pigeon peas. Seeds that are harvested green, like green peas or green beans are classified as vegetable crops, not pulses. Legumes used primarily for oil extraction, like soybeans, are also not pulses. [2]

Why are pulses getting a year-long, world-wide campaign?

A global push for pulse production would address many problems of our global food system. The Food and Agriculture Organization of the United Nations’s campaign highlights these key benefits to pulse cultivation [1]:

  • Pulses are highly nutritious – they are excellent plant source of protein, and contain the B vitamins that our bodies require to convert food to energy
  • Pulses are economically accessible and contribute to food security at all levels – from farmers to consumers
  • Pulses foster sustainable agriculture, thus addressing agriculture’s role in climate change
  • Pulses promote biodiversity in agriculture


Now that we know the basics of pulses and why they’re important, let’s get scientific.


Photo credits: (flickr/Kelly Garbato)

Pulses in the nitrogen cycle

Pulses are legumes, or plants in the family Leguminosae. Thanks to their symbiosis with many members of the diazotrophic, or nitrogen-fixing bacterial genus Rhizobium that live in their roots and feed them with nitrogen from the air, pulses have a particularly high protein content compared to non-legumes. [3] Within the bacterium, atmospheric nitrogen (N2), which is typically unusable to plants, is converted to ammonium (NH4+) via the activity of the enzyme nitrogenase. The nitrogen of ammonium is converted to other more complex compounds that are beneficial to humans, like amino acids – the building blocks of protein. In exchange for fixing nitrogen, the bacterium receives food from the plant — carbon in the form of glucose (C6H12O6).


This remarkable bacterial symbiosis also enriches the soil in which pulses grow with nitrogen compounds like nitrite (NO2) and nitrate (NO3), which is the preferred nitrogen source for other green plants. For this reason, farmers who crop-rotate with legumes don’t need to apply nearly as much fertilizer as farmers who don’t. [3]

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Pulses in a changing climate

Many pulses are also hardy and drought tolerant crops – lentils, broad beans, peas, and chick peas are all native to the Fertile Crescent of the Near East, and have adapted to sprout quickly and reproduce in the rainy season before the hot, dry summer [3].

Anatomy of the pulse

All food seeds consist of three basic parts: an outer protective coat, the small embryonic portion that develops into the mature plant, and the storage tissue that feeds the plant embryo. [3]The bulk of the seed consists of storage cells are filled with particles of concentrated protein and granules of starch, or organized masses of starch chains.

Cooking and starch retrogradation

When we cook pulses, hot water permeates the starch granules. As the water molecules work themselves between the starch chains, the granules swell and soften. When the pulses later cool down, the starch chains bond to each other again in tighter, more organized associations, resulting in firmer granules. (This process is called retrogradation.) [3] Consider leftover lentils or beans: they’re always harder and drier the next day, and they never get quite as soft as when they were first cooked. This is because during the process of retrogradation, some starch molecules form granules that are even more tightly associated than the bonds in the original starch granule. They form small crystalline regions that resist breaking even at boiling temperatures. [3]

Retrogradation of starch might foil your plans for leftover lentils, but it does do our bodies good: Our digestive enzymes cannot easily digest retrograded starch, so eating it results in a more gradual rise in blood sugar compared to the effects of non-retrograded starch. [3] Our intestines need help breaking down this tough starch, and the beneficial bacteria in our large intestines are happy to be of assistance. Just as the diazotrophic bacteria in soil work in harmony with leguminous plants, our intestinal bacteria digests what we cannot. Thus the retrograded starch functions as a prebiotics, or food for the probiotic bacteria in our guts. Well-fed gut bacteria make for healthy digestive tracks and happy bowels.

Will this pulse promotion save the world and fix the global food economy? Perhaps. We can all do our part by making a hearty spinach dal for dinner tonight, and sweet red bean paste for dessert.


Works Cited

  1. “”Save and Grow in Practice” Highlights Importance of Pulses in Crop Rotations and Intercropping.” Pulses – 2016 | 2016 International Year of Pulses. Food and Agriculture Organization of the United Nations, n.d. Web. 05 Feb. 2016.
  2. “What Are Pulses? | FAO.” What Are Pulses? | FAO. Food and Agriculture Organization of the United Nations, 15 Oct. 2015. Web. 05 Feb. 2016.
  3. McGee, Harold. “Seeds.” On Food and Cooking: The Science and Lore of the Kitchen. New York: Scribner, 2004. N. pag. Print.

Elsbeth SitesAbout the author: Elsbeth Sites received her B.S. in Biology at UCLA. Her addiction to the Food Network has developed into a love of learning about the science behind food.

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