Garlic

Image Credit: Robert Benner (mullica/Flickr)

Image Credit: Robert Benner (mullica/Flickr)

If you’ve ever made the mistake of devouring three bowls of James Beard’s Garlic Soup a few hours before The Job Interview Of Your Life (I’m not speaking from experience here), you will recognize the frantic moment in which you pray that 1) the handful of mints burning in your mouth have superpower strength, or 2) your interviewers cannot smell, or 3) whoever you’re meeting had four bowls of garlic soup. Ahhh, the allure and woe of garlic. Why do you hate me if I love you so much?

Known for its distinct aroma and taste, Allium sativum – or garlic, as most of us know it – makes dishes sweet and pungent while it turns breaths foul and fetid. But what exactly causes garlic breath? More importantly, how do you get rid of it?

Image Credit: (fiverlocker/Flickr)

“Dear god, what did this guy have for lunch?”  —  Image Credit: (fiverlocker/Flickr)


The Breakdown of Garlic Breath

Garlic contains many sulfur compounds, but the ones most responsible for garlic breath are: diallyl disulfide, allyl methyl disulfide, allyl mercaptan, methyl mercaptan, and allyl methyl sulfide (AMS). The gases released by all of these compounds, except forAMS, originate in the oral cavity when we mechanically crush garlic in our mouths, so brushing your teeth and tongue will reduce the presence of the mouth-originated odors. However, good dental hygiene doesn’t usually entirely get rid of the smell because AMS is what causes unwelcome garlic breath, and this can linger for several hours or even days.

Background Credit: Crispin Semmens (conskeptical/Flickr)

Allyl Methyl Sulfide (AMS), the unwanted pungent houseguest that overstays its welcome. — Background Credit: Crispin Semmens (conskeptical/Flickr)

AMS is a sulfur compound formed inside the body from allyl mercaptan, so instead of originating in the mouth, AMS is produced in the microflora of the gut. The resultant gas quickly evaporates into the bloodstream, which then diffuses to the lungs and infuses each breath of air that leaves our bodies with traces of strong-smelling allyl methyl sulfide. And if that isn’t wonderful enough, the compound is also released through pores of the skin, which is why you may notice a lingering body odor after garlic-heavy meals. Unfortunately, AMS does not get metabolized in your gut and liver like many other molecules that we eat, so it takes much longer for AMS to breakdown – which is why the AMS stays in the body for many hours later. [1]

SOLUTIONS: When brushing your teeth (sadly) isn’t enough

Image Credit: Robert Bertholf (robbertholf/Flickr)

Image Credit: Robert Bertholf (robbertholf/Flickr)

  • EAT THIS: Parsley, Spinach, Mint, Apples, Pears, plus any fruits and veggies that are prone to browning (think avocados, bananas, potatoes, etc.)

    WHY: These foods contain an enzyme called polyphenol oxidase. (The same enzyme is what makes your fruit salad look brown!). When this compound is exposed to oxygen, it reacts in a way that reduces both the odors of the volatile compounds and the formation of more AMS. [2]

Image Credit: A Girl With Tea (agirlwithtea/Flickr)

Image Credit: A Girl With Tea (agirlwithtea/Flickr)

  • DRINK THIS: Green Tea, Coffee,  Ku-Ding-Cha (a bitter-tasting Chinese tea),  Prune Juice

    WHY: These drinks contain a polyphenolic compound called chlorogenic acid, which is another chemical that works to deodorize garlic-derived sulfur compounds on human breath. [2]

Image Credit: (Unsplash/pixabay)

Image Credit: (Unsplash/Pixabay)

  • ALSO DRINK THIS: Lemon juice, Soft Drinks, Beer, Hot Cocoa (and other acidic foods/beverages)

    WHY: When garlic cloves are cut or crushed open, they release an enzyme called alliinase that facilitates the reactions which produce compounds responsible for the smell of garlic. Because these drinks have a pH below 3.6, they quickly destroy alliinase and minimize the formation of garlic volatiles. [2]

Image Credit: Mike Mozart (jeepersmedia/flickr)

Image Credit: Mike Mozart (jeepersmedia/flickr)

  • DRINK THIS INSTEAD OF WATER: Milk!

    WHY: While drinking water works extremely well for reducing garlic breath, milk works even better because of its extra fat, protein, and sugar. Specifically, whole milk is effective in the reduction of the hydrophobic compounds diallyl disulfide and allyl methyl disulfide because of its high fat content. Note that drinking milk during a garlic-heavy meal does a better job of killing garlic breath than drinking milk afterwards, because the milk is able to directly react with the volatile compounds when it is mixed with garlic. [3]

Makes me think garlic ice cream might actually be a genius all-in-one odor-neutralizing dessert!

References Cited:

  1. Suarez, F., Springfield, J., Furne, J., Levitt. M. Differentiation of mouth versus gut as site of origin of odoriferous breath gases after garlic ingestion. Am J Physiol. 1999; 276(2):425–30.[http://ajpgi.physiology.org/content/276/2/G425]

  2. Munch, R., Barringer, S.A. Deodorization of Garlic Breath Volatiles by Food and Food Components. Journal of Food Science. March 2014; 79(4): C536-533.

  1. Hansanugrum, A. Barringer, S.A. Effect of Milk on the Deodorization of Malodorous Breath after Garlic Ingestion. Journal of Food Science. August 2010; 75(6): C549-558.


Eunice LiuAbout the author: Eunice Liu is studying Neuroscience and Linguistics at UCLA. She attributes her love of food science to an obsession with watching bread rise in the oven.

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Fruit Images & Wasabi Meds

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Yes, that’s a strawberry as seen from under the microscope. Wait ’til you see what a peach looks like zoomed in. For more “Whoa!”, the burn from wasabi could be useful in developing new pain medications.
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Lobsters: A Crustacean Sensation

Photo credit: Flickr/Stacylynn

Photo credit: Flickr/Stacylynn

They lurk in the depths of the ocean, feasting on the remains of their fallen neighbors. With stalked eyes, muddy coloring, and large predatory claws, they’re reminiscent of insects and are admittedly neither cute nor cuddly. They’re ancient, they’re cannibalistic, and they’re delicious dipped in lemon and butter. They’re the beloved lobsters, a crustacean sensation.

Lobsters have spent decades clawing their way up social and culinary ranks, rising from their status of an aquatic beach pest to the iconic culinary symbol of New England as we know them today. In early America, lobsters would wash up on Boston beaches after storms and litter the shores with their decomposing bodies. Piles of carcasses would collect and rot, prompting frustrated New Englanders to put them to good use. The festering carcasses were harvested and ground into a slurry, which was then used as fertilizer or fed to prisoners and peasants as a high-protein fuel [1]. Clearly, lobsters were hardly symbolic of fine dining and affluence. Lobsters were so reviled that indentured servants in Massachusetts often signed contracts refusing to eat them more than three times a week, deeming such treatment as being cruel and unusual.

In the mid-1800s, railways overtook America as the dominant mode of transportation and led the lobster on its journey to popularity. Train managers exploited the low cost of small lobsters and fed them whole to unsuspecting inland customers, touting them as a rare and exotic delicacy. Satisfied customers quickly spread word of this new luxury food, and thus began the rise of the lobster. With the help of this clever rebranding, lobster meat began appearing in restaurants alongside salad bar toppings and gained wide recognition not only as a viable source of protein, but also as a respected food item. By World War II, lobsters became integrated into American society as a luxury [2].

Whether they’re plucked straight from the sea or from a tank at the grocery store, there are few foods that beat a freshly cooked lobster. Many of us squirm at the prospect of plunging a live lobster into a bubbling vat of doom, viewing the act as a cruel, but necessary sacrifice we must make in order to eat it. So what is it that compels us to cook them live in the first place? A major turning point in its culinary standing was when chefs realized that lobsters taste better when cooked alive. Cooking live shellfish preserves the structural integrity of the meat and gives a sweeter and cleaner taste, in stark contrast to the putrid flavors that can develop in the mushy flesh of deceased lobsters [1]. The biochemistry of death accounts for this change.

The inside of a dead lobster serves two purposes: it’s a hub for several enzymatic reactions, and it’s a breeding ground for rogue bacteria. Upon death, proteolytic enzymes are activated and attack the lobster’s internal organs. Once under attack, these organs release another wave of enzymes into the lobster’s muscle tissue. A major player here is the liver, which houses a multitude of proteases reserved for digesting food. These digestive proteases, along with the first wave of enzymes, leak out and begin degrading muscle tissue, by breaking collagen and other proteins down into smaller peptides, polypeptides, and amino acids. Given how rapidly these enzymes work, it’s only a matter of time before the lobster’s flesh turns to mush.

Additionally, many nutrient-producing enzymes are also activated upon death. These newly-produced nutrients cause trouble by encouraging bacterial proliferation. As bacteria begin multiplying inside of the lobster, they produce metabolic waste products along with their own brand of proteases, many of which lend to the off-flavors and textural defects found in deceased lobsters. To save the lobster meat from succumbing to textural degradation or bacterial contamination, iced storage or evisceration are often recommended to minimize enzymatic activity. Rapid heating via boiling or steaming, however, still remains the best-known way of rapidly deactivating these enzymes. Bacterial contamination in shellfish can also lead to food poisoning and other complications, so not only does freshly killed seafood taste better, but it’s also much safer to eat. Cooking live lobsters allows us to minimize the ill-effects between death and consumption and spares us from suffering any gastric mishaps [5].

You’ve tossed the lobsters into the pot now—what’s actually going on under that furiously clanking lid? Maybe you’ll hear them thrashing around or a hissing sound as steam escapes from their shells. One thing you’ll also notice as the lobster cooks is its color change—from a blue-black to a brilliant red-orange. A lobster’s muted coloring provides camouflage when it’s prowling around in the sea. Uncooked, a lobster’s shell contains α-crustacyanin, a complex formed when a protein binds with pigmented carotenoids derived the crustacean’s plankton-heavy diet [3]. On their own, carotenoids are richly colored and can range from yellow to red, and they’re also credited with providing sweet potatoes, carrots, and tomatoes with their vibrant colors. When bound to proteins inside a lobster shell, they’re blue. As heat is applied, the α-crustacyanin protein complex denatures and releases free carotenoids. Astaxanthin, the main pigment molecule, is now exposed and provides cooked lobsters with their characteristic red hue [6].

Artwork credit: Michael Kim

Artwork credit: Michael Kim

Within the shell, a lobster’s meat acquires those sweet and nutty aromas we’ve come to associate with seafood and summer. There are more than just cultural influences that have made lobsters desirable; it’s the very chemistry of lobster meat that sets it apart from others. When was the last time you invited company over for dinner and decided to serve boiled steaks? You probably never have. There’s a reason you fired up your grill—and that’s because grilling produces a far more flavorful steak. Cooking at higher temperatures associated with roasting or grilling triggers the beloved browning/Maillard reaction known to impart complex flavors onto your food. A unique feature of lobster meat that it undergoes the Maillard reaction at much lower temperatures than other meats like beef, chicken, or pork. As it turns out, lobsters actually have an unusually high concentration of free amino acids and sugars in their muscle tissue. This abundance of free amino acids more readily undergo these flavor-producing reactions at much lower temperatures than would be re-quired in other types of meat. This is why you can get away with boiling lobsters and shell-fish and still manage to produce incredible flavors (3).

Lobsters are a delight to the masses. They’ve amused countless children at the grocery store in their tanks and they’ve satisfied hungry adults alike. Whether you’re considering its history, culinary uses, or chemistry, the lobster truly is a sensation.

Lobsters3

References cited

  1. Wallace, David Foster. “Consider the Lobster.” Consider the Lobster And Other Essays. New York: Little, Brown, 2005.
  2. Daniel Luzer. “How Lobster Got Fancy“. Pacific-Standard.
  3. McGee, Harold. On Food and Cooking: The Science and Lore of the Kitchen. New York: Scribner, 2004. Print.
  4. Vieira, Ernest R., and Louis J. Ronsivalli. Elementary food science. New York: Chapman & Hall, 1996. Print.
  5. Proteases in fish and shellfish: Role on muscle softening and prevention. International Food Research Journal 21(1):433-445. Sriket, C. 2014.
  6. Begum, S., et al. 2015. On the origin and variation of colors in lobsters carapace. Phys. Chem. Chem. Phys.

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.

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Making Fake Meat Real: How Scientists are Tricking Your Tongue

Fake meat is often associated with a tough, flavorless texture that is added to dishes to provide protein. However, fake meat is no longer just glutinous balls or tofu hidden beneath sauces. From plant protein derived meats to in vitro preparations, there is much more to synthetic meat than what meets the tongue.

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Veggie Sausage. Photo Credit: (Heather Quintal/Flickr)

Replicating meat texture

Meat texture is very complex. Consider the multiple components from muscle tissue fibers, blood vessels, fat, gristle, to nerves. Each component confers a different texture and flavor profile, so replicating meat is quite a challenging process.

Texture plays a big role in determining whether a product tastes like real meat or not. For example, the satisfyingly stringy texture one gets from pulling apart chicken strips. Fortunately, food scientists have found ways to emulate the fibrous quality in fake meat using soy protein. Soy protein is initially globular, so it must be denatured, or broken down, to make it more fibrous. Soy protein is first exposed to heat, solvent, or acid, before it is reshaped with a food extruder [1]. Extrusion processes are useful as they can form meat analogs with fibrous matrices, which can then be rehydrated into meat like substances [2]. However, this process can sometimes result in a dry product. The rising company Beyond Meat has gone further and found a way to use soy flour, pea flour, carrot fiber, and gluten-free flour to emulate the fibrous quality in their fake meat with a wet extrusion process. The proteins are realigned and then locked in position by crosslinking to get a fibrous chicken imitation that is also moist and juicy [1].

Taste & color of meat

The flavors of meat mostly arise during the cooking process. Maillard reactions between sugar and amino acids produce those familiar meat flavors and aromas [3]. The amino acid glutamate is of utmost importance as it activates the umami taste receptors. Real meats contain glutamate as it is found in proteins, and it is released during proteolysis that occurs during meat aging and cooking [4]. Since most fake meats do not contain glutamate, this taste can be added back with soy sauce, tomatoes, mushroom, and cheese in the form of sauces [5]. Another unique aspect of meat is its color. The myoglobin proteins found in muscle are initially red due to heme pigments, but with the added heat of cooking, protein denaturation results in a brown color associated with cooked meat. For fake meat, food colorings and spices can be used to mask the original color.

In vitro meat: your steak from a petri dish

To minimize the number of animals slaughtered, some scientists are even growing animal tissue in the lab [3]. To do this, they take a small muscle tissue sample and look for skeletal muscle satellite cells, which are essentially individual stem cells that are normally used to create new tissue in case of damage. After these satellite cells are collected, they are bathed in a nutrient serum where they can be coaxed into growing. When large enough, they are shocked with an electric current, which causes the tissue to contract and thicken, resembling small fillets of meat a couple centimeters long and a few millimeters thick [3]. While meat products generated using this process are not available at your local supermarket (or butcher), and this product is not truly “meat-less” for vegetarians or vegans, it could potentially maximize meat production by saving cows from the slaughterhouse.

In vitro meat samples. Photo Credit (Janique Goff/Flickr).

In vitro meat samples. Photo Credit (Janique Goff/Flickr).

Fake meat efforts are attracting big investments from Bill Gates and Silicon Valley entrepreneurs, as the demand for meat increases. In fact, population growth and a boost in meat consumption have increased the global demand for meat threefold in the last 40 years [6]. Not only does this intensify the requirements for raising livestock, but it also increases the greenhouse gas emissions emitted during processing [6]. It is no wonder that the search for the best meat-replication process continues on! Whether from an animal or plant base, synthetic meat is becoming increasingly prevalent and is not just for vegetarians and vegans anymore.

References cited:

  1. How ‘fake meat’ is made. Mother Nature Network.
  2. Riaz, Mian N., Anjum, Faqir M., Khan, Muhammad Issa. “Latest Trends in Food Processing Using Extrusion Technology.” The Pakistan Society of Food Scientists 17.1 (2007): 53-138. Web.
  3. Fake meat: is science fiction on the verge of becoming fact? The Guardian.
  4. The Chemistry of Beef Flavor. BeefResearch.org.
  5. What Foods are Glutamate-Rich? Msgfacts.org.
  6. The Bill Gates-backed company that’s reinventing meat. Fortune.

Catherine HuAbout the author: Catherine Hu is pursuing 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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Sour Beers & Skunky Beers

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“Fermenting yeasts produce more than just ethanol and carbon dioxide. They make flavorful, aromatic molecules: acids and esters. But which ones make which ones?” wonders William Bostwick as he attempts to recreate a sour beer in his kitchen in San Francisco’s Mission District. If you’re more interested in preventing your beer from getting skunky than making your own, we found some chemistry to help you out.
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Could Making Beer From Sewage Save Us From The Drought?

[Photo Credit: Vince C Reyes]

[Photo Credit: Vince C Reyes]

The historic drought in California and other U.S. states challenges us to rethink the way food production and consumption shapes our available water supply. To that end, one adventurous brewing club, The Oregon Brew Crew, collaborated with Oregon’s water utility, Clean Water Services, to brew beer from waste water. This comes as part of the water utility’s initiative to make better use of recycled water. As beer is 95% water, we could potentially save significant volumes of water through this less glamorous route.1

To be clear, the brewers did not make beer straight from water entering out of the toilets and sewers of Oregon. Clean Water Services provided the brewers with “ultrapure water” for making their beer. Ultrapure water is made from water that is purified using the most advanced water treatment methods available. Ultrapure water is not new, but is normally not used for brewing. It is traditionally used for generating water for electronics and pharmaceuticals production, scientific research, or any other application where water must be free from as many contaminants as possible.

To generate ultrapure water, Clean Water Services combines traditional wastewater treatment with more advanced methods. For this process, sewage is first cleaned using traditional wastewater treatment, which includes screening, sedimentation, biological treatment, and disinfection. After this step, the sewage is fit to be released to lakes and rivers, but gets a deeper cleaning through more advanced methods. In the case of the water used by the brewers, Clean Water Services uses a three-step process of Ultrafiltration, Reverse Osmosis, and Enhanced Oxidation to produce their ultrapure water.

The water is first subject to Ultrafiltration and Reverse Osmosis. These processes work like a kitchen sieve as they push water through small pores in a barrier to separate water from different molecules. While both Ultrafiltration and Reverse Osmosis use similar physical separation mechanisms, they vary in the products they can remove from water because of their differing pore sizes. Ultra-filtration can be used to remove particles as small as viruses and bacteria (0.005 – 0.5 μm), while Reverse Osmosis uses finer pores, which can remove even smaller molecules like herbicides, pesticides, salts, and metal ions (0.0001 – 0.001 μm) (Figure 1).

Figure 1: The size of materials that can be removed by Ultrafiltration and Reverse osmosis. Figure Credit: Designerwater.co

Figure 1: The size of materials that can be removed by Ultrafiltration and Reverse osmosis. [Figure Credit: Designerwater.co]

In contrast to Ultrafiltration and Reverse Osmosis, the final step, Enhanced Oxidation, uses chemical methods to eliminate any remaining unwanted products in water. Specifically, Enhanced Oxidation uses ultraviolet (UV) light in combination with chemicals like hydrogen peroxide (H2O2) and ozone (O3) to generate hydroxyl radicals. The high energy from the UV light breaks down chemical bonds to form hydroxyl radicals (·OH). For example, here is the break down of hydrogen peroxide by UV light:

H2O2  + UV -> 2·OH

A hydroxyl radical is just a hydrogen atom bonded to an oxygen atom with an extra electron. Having an extra electron makes hydroxyl radicals very reactive and can break down undesirable molecules in water. This final step removes any remaining contaminants that were not eliminated by Ultrafiltration and Reverse Osmosis.

Figure 2: Ultrapure water (high purity water) compared to river water, cleaned sewage water, and tap water. [Image Credit: huffingtonpost.com]

Figure 2: Ultrapure water (high purity water) compared to river water, cleaned sewage water, and tap water. [Image Credit: huffingtonpost.com]

After these three treatments, the ultrapure water was ready to be used for brewing. In regards to taste, this process produced bland tasting water that results from the absence of minerals and salts that are normally found in water from groundwater, reservoirs, lakes, rivers, and the tap2. These atoms and molecules can be challenging for brewers, as they impart a natural flavor to waters that may not be congruent with the desired beer’s flavor profile3. Instead, when using ultrapure water, the brewers had the freedom to build in whichever flavors they desired. The hops, grains, yeast, and additional spices controlled the beer’s flavor profile rather than the water.

Currently in the U.S., recycled water typically cannot be used directly as drinking water, regardless of how much it is cleaned. Generally, recycled water is only used to water landscape, cool power plants, or flush the toilet. But with growing concerns over shrinking water sources, these views are changing. In 2010, a study by the California State Water Board examined the potential contaminants in recycled water, current water treatment technology, and human health studies of exposure to these contaminants. The conclusion was that recycled water could be safe for human consumption4. These results have been confirmed by other research as well5.

Projects like this may cause you to re-evaluate your bias about the source of your water (and beer). Regardless of the origin of your water, advances in water treatment technologies may enable us to produce safe drinking water from wastewater. But the question still remains: would you feel comfortable raising a glass of beer made from recycled waste water to your lips or would you pour it down the drain?

Learn More

  1. Water and Wasterwaster: Treatment/Volume Reduction ManualBrewers Association.
  2. Is Sewage Beer The Next Big Thing?Huffington Post.
  3. To Grow A Craft Beer Business, The Secret’s In The WaterNPR: The Salt.
  4. Final Report: Monitoring Strategies for Chemicals of Emerging Concern (CECs) in Recycled WaterState Water Resources Control Board.
  5. Rodriguez, C., Buynder, P.V., Lugg, R., Blair, P., Devine, B., Cook, A., Weinstein, P. Indirect Potable Reuse: A Sustainable Water Supply Alternative. International Journal of Environmental Research and Public Health. March 2009; 6(3): 1174-1209.

Vince ReyesAbout the author: Vince C Reyes earned his Ph.D. in Civil Engineering at UCLA. Vince loves to explore the deliciousness of all things edible.

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