Molecular Gastronomy

The chemistry behind baking

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The Science Behind Eggs

Depending on the recipe, most baked goods require the use of eggs. Believe it or not, eggs serve a crucial role in many recipes, but cooking the perfect egg often proves to be a difficult task. This one simple ingredients has a series of characteristics, which can very depending on the method used to cook the eggs.

Factors that affect the cooking time of eggs:

Age of  the eggs: There is a specific bonding between the inner membrane of the eggs and the egg whites. This bond can be specifically be seen in fresh eggs from a farm, which is why they are often difficult to boil/cook. These type of eggs can be best used for frying. On the other hand, this bond eventually breaks down overtime, making it easier to boil/cook eggs found at a supermarket.

Protein Bonding Temperature: Egg whites contain certain proteins, that can bond together. These bonds affect the appearance and structure of the egg, as these bonds can lead to the rubbery texture of the egg white that can sometimes be found in hard-boiled eggs. Between 30-140°F, the proteins of the egg whites expand. Above 140°F, the proteins will bond and after 155°F, the proteins will solidify. At around 180°F, the proteins will bond together, giving the opaque and firm characteristics of the egg white. Any temperature above 180°F may lead to the release of hydrogen sulfide, which is responsible for the smell of rotten eggs, as well as the dark green-grayish compound located between the egg white and yolk if overcooked.

Egg Yolk Temperature: The egg yolk is mainly composed of fatty acids, cholesterol, and some proteins. Because of this, different temperatures affects its performance. An egg cooked at any temperature below 145°F will have no affect on the yolk. Once reaching a temperature around 160°F, the yolk will become firm but it will still retain its bright color. Any temperature over 170°F will cause the yolk to turn a pale yellow, and it will have a crumbly consistency. This will result in its chalky texture and it will also release ferrous sulfide, which is also responsible for the smell of rotten eggs.

Altitude: Altitude also plays a key role in cooking an egg as altitude affects the boiling temperature of water. According to the U.S Department of Agriculture (USDA), the boiling temperature at a point above 2,000 feet is around 208°F, lower than the ground level boiling temperature of 212°F. Due to this difference, it will take more time to properly cook an egg at higher levels than that of lower levels.

On the other hand, there are also many ways to prepare eggs, with each method having its own scientific background to it.

Science Behind Various Methods of Preparing Eggs:

Heating: When heating eggs, the egg-white proteins move around and collide with water molecules. Due to this, weak bonds may break, causing the egg white proteins to uncurl and collide with other proteins that have uncurled as well. This results in new chemical bonds, connecting different proteins to one another. The breaking of bonds and formation of new bonds allow for the egg white proteins to form a series of interconnected proteins. These bonds are responsible for the ability of the egg whites to develop a rubbery texture, which was previously discussed in the “Protein Bonding Temperature” paragraph located earlier in this post.

Beating/whipping: Beating or whipping eggs exposes air bubbles to egg whites. This exposure allows the unfolding of the egg proteins just as heating would unfold these proteins. Egg-white proteins consist of both hydrophilic and hydrophobic amino acids. In other words, some amino acids are attracted to water, while others are repelled by it. Prior to uncurling, the hydrophobic amino acids are located in the center away from the water, while the hydrophilic amino acids are located closer to the water. When the egg-white protein encounters an air bubble, part of the protein is exposed to both air and water. This causes the protein to uncurl so the hydrophilic and hydrophobic amino acids can be located in its desired respected area. This allows the amino acids to bond with each other, creating a series of bonds that hold the air bubbles in space. When heating the air bubbles, the gas inside them expands. Often, the area around the bubble solidifies, and the structure usually does not collapse when the bubbles burst. The protein that lines the outside of the air bubbles is known as lecithin. This is what prevents them from collapsing when baking. This allows for the consistency found in a soufflé or meringue. The more whipped the egg whites are, the more stiff they will become. On the other hand, unbeaten egg whites often allow the lecithin as a binder, which hold the cake together.

Here’s an interesting fun fact: There is a myth stating that copper bowls are better for whipping eggs. There is some actual scientific support to this myth, proving that it is true.  The copper ions from the bowl combine with conalbumin, one of the proteins found in eggs. This combination forms a bond that is stronger than the protein itself, making it less likely for the egg-white proteins to unfold. The copper could also react with sulfur-containing groups on other proteins found in eggs, making the egg proteins even more stable. If a copper bowl is not used, ingredients such as cream of tartar or vinegar can be used to produce a similar effect.

Mixing: Many recipes call for the mixing of oil-based and water-based liquids. However, these two are immiscible and do not interact with one another. Because of this, egg yolks are often used to create an emulsion. Egg yolks contain a number of emulsifiers, with some of them being hydrophobic and others being hydrophilic. Because of this, thoroughly mixing egg proteins with oil and water will allow part of the protein to attract the water and another part to attract the oil.

Just like egg-whites, egg yolks contain lecithin. The lecithin, which is a phospholipid, also acts as an emulsifier. Due to its structure (see figure below), it has a hydrophilic head and a hydrophobic tail. The tail gets attracted to the oil, while the head gets attracted to the water.

These important characteristics of egg proteins play a crucial role in making foods such as mayonnaise, which require the mixing of water and oil.

On a side note, eggs can also be used as moisteners (instead of using water) and a good source of fat and amino acids. It can also be used as a glaze as a source of protein for the Maillard Reaction.

So next time you bake, don’t forget to note the complex structure and characteristics of an egg…it is because of this that eggs are used in various methods of cooking. Not only does an egg serve for taste, but it also plays a vital role in the texture or appearance of certain kinds of food.

Author: Erica Rowane Bautista


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Yeast in All its Glory

Once you step into a kitchen, the baker becomes the chemist and the recipe the experiment. In the following, we will explore the relationship of yeast to the staple of baked goods, bread. The baker combines flour, yeast, liquid, and salt in a bowl, forms a dough which is then left to rise and baked in a hot oven.

As the grain seeds used for flour are crushed, starch and proteins are released. Starch molecules are long, gangly polymers of simple sugars linked head to tail by chemical bonds. Proteins are more complex as a single protein may contain hundreds of amino acids strung together. But what causes that amazing fluffy texture one aspires to produce? Well this answer lies in the proteins gliadin and glutenin. They swell like sponges when kneaded with water and form the tough but elastic gluten. It is essential for gluten to stretch and trap the gaseous bubbles that make dough rise which in turn comes from yeast.

So essential to bread are those fungi, yeast. Unwitnessed by the naked eye, enzymes from the yeast cells attack starch, breaking it down into glucose. In addition, other enzymes transform glucose molecules into carbon dioxide and ethanol through glycolysis and fermentation. The carbon dioxide gas is released as a by product causing the dough to rise. Yeast can ferment or respire depending on the condition. With aerobic metabolism the yeast gain more ATP, energy, through respiration but in anaerobic metabolism,fermentation occurs.

Baking powder vs. Yeast
If baking powder is used instead of yeast do not have the same fermented molecules that give gread a great taste. When the baking powder gets wet, a chemical reaction occurs that releases only carbon dioxide, salt, and water. With yeast however, the yeast cells grow under anaerobic conditions and are not able to convert glucose molecules completely to gas. Some of the sugar molecules are converted to alcohols, acids, and esters which in turn add additional flavor.

Slower? Faster?
Water from boiling potatoes, eggs or sugar serve as a catalyst in yeast growth.
Salts and fats like butter slow down yeast growth. Salts effectively slow down the enzymes which catalyze the breakdown of proteins, strengthening gluten. But be careful, adding the perfect amount can be tricky. Too little and your dough will be tough and sticky. Too much, and water flows out of yeast cells by osmosis. If this happens, nutrients are lost and production of carbon dioxide is slower than normal.

In the Oven:
Once risen, the pockets of gas in the dough expand further in the oven. Because lactose is not fermented by the yeast, it is present in the bread to undergo a browning process. At 175 °C, lactose turns brown which is due to either caramelization reactions (formation of burnt sugar) during baking and storage or the Maillard reaction. The Maillard reaction occurs between a reducing sugar such as lactose, and the amino groups of proteins. They compose the major flavor and aroma of bread crust. Yet again, the alcohol from fermentation add to bread flavor. The optimal temperature for yeast to ferment sugar is 32°C and if the temperature is warmer, 45 °C, the yeast cells will die.

Try this fun experiment to get a hands on understanding of what occurs.

What you will need:

baker’s yeast
3 beakers 100 mL
3 snap-cap vials 20 mL
glass stirring rod
watchglass d = 8 cm

What to do:
1. Fill the three 100 mL beakers with 40 mL of water
2. 10 g of the appropriate sugar is dissolved each beaker
3. 1 g of baker’s yeast is added to each of the sugar solutions.
4.The solutions are warmed on the hotplate to a temperature around 25 to 40 °C.
       super easy (:

What you may expect:
Different amounts of visible foaming will occur in each beaker- a visible sign of the release of carbon dioxide from the reaction. The strongest will be in sucrose and slightly less in fructose while none will be seen in lactose as the yeast can no longer react with lactose.

Author: Liat Kugelmass


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How Does High Altitude Affect Baking?

As with any amateur baker hoping to rise in the ranks and finally trade in that Easy-Bake oven for the real thing, one must master the manipulation of temperatures, moisture levels, and precise ingredient measurements, whose slight deviation from ideal could render a cake dry or a brownie crusty (gross), before he/she may be rightfully deemed a skilled baker. A factor that many do not take into account while baking, however, is that of a change in altitude and in turn, in air pressure. Since most recipes are designed for baking at sea level, grasping how changes in altitude affect the baking process is essential to understanding why certain modifications are necessary to counteract such effects and to producing the perfect baked good at a high altitude (>3,000 feet above sea level). Who knows? In 10 years’ time, you could be training to be a mountain cook and thanking me for providing you with your first exposure to the chemistry behind high altitude baking.

In order to facilitate a comprehensive delivery on my part of all the factors that influence the baking process at high altitudes, I will address three significant changes that come hand in hand with a change in altitude and collectively represent the answer to the question posed in the title of this post. For one, water boils at a lower temperature with a rise in altitude.

Elevation    Boiling Point of Water
Sea Level 212 ºF
3,000 ft 206.7 ºF
5,000 ft 203.2 ºF
7,000 ft 199 ºF
10,000 ft 194.7 ºF

Why does going up in elevation result in a lower boiling point? Let’s take a minute to consider prior knowledge. If it is known that atmospheric pressure decreases as altitude increases and that the boiling point of a liquid represents the temperature at which its vapor pressure is equivalent to the atmospheric pressure, then it may be concluded that at higher altitudes, the vapor pressure of the liquid could level with the atmospheric pressure at a lower temperature. The greater length of time necessary to bake goods at higher altitudes may be attributed to this observation, as the lower temperature impedes the chemical and physical reactions that take place during baking and cooking. Secondly, liquids are more volatile at higher altitudes. If the boiling point (the temperature at which a liquid may vaporize or a gas may condense) of a liquid is lowered at higher elevations as previously mentioned, then it follows that liquids are also more apt to vaporize or have an increased volatility at greater heights. Then, what does this mean for your baked goods? Moisture would leave your baked goods much more readily at a higher altitude, potentially jeopardizing the overall structure of the goods and subduing the flavor now that there are fewer moisture molecules to carry the aroma. Lastly, air bubbles more readily expand and rise at high altitudes. With a low atmospheric pressure, there is less of a force over the given area counteracting the push of the gases within, resulting in the rapid expansion of leavening gases or bubbles formed from the air, carbon dioxide, and water vapor that rise in products with yeast, baking soda, or baking powder. The next time you go trekking through a mountain and are suddenly overcome by a craving for baked goods, recall these chemical applications to assist you in your baking endeavors!

Check back later for more on the chemistry behind baking! (:

Author: Carrie Xu

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Scientific Ice Cream

“It’s NEVER too cold for ice cream.” -Anonymous

Have you ever wondered how making ice cream the old-fashioned way actually works? Well, let’s say one night, you put both a water bottle and a container of vanilla ice cream in the freezer. The next day, when you open the freezer, the water bottle is frozen and rock-hard. But what about the ice cream? Why does the ice cream remain solid-like but still slightly soft? This is because ice cream has a lower freezing point than water. Ice cream contains many particles, which makes it harder for the water molecules in the ice cream to push the particles out of their way and become solid to form ice. The lowering of the freezing point of a liquid by adding compounds to it is known as freezing point depression. This is exactly what occurs in the process of making ice cream!

To get an idea of what freezing point depression is and how it works, refer to the diagram below:

The vapor pressure of the solution is lower than that of the pure solvent. Therefore, the freezing point is also lowered.

You can also see in this picture of a heating curve, the curves for a pure liquid and solution (liquid with added impurities):

See how the freezing point of the solution is lower than the freezing point of the pure liquid. As I stated before, this is because the solution has added particles into it that the pure liquid does not have, making it more difficult for water to reach the order and organization required to form ice.

To better understand this concept, you can think of freezing point depression in the process of making ice cream. Here’s a recipe for how to make ice cream (you can try it out!):

  • One sandwich-size Ziploc bag
  • Larger Ziploc bag
  • Sugar
  • Cream or milk
  • Vanilla extract, or other flavoring
  • Rock or coarse salt
  • Measuring cup and spoons
  • Crushed ice cubes or “party” ice

  • 1. Make up the ice cream mixture by adding to the smaller bag:
    – 100mL (1/2 cup) of cream or milk
    – 25mL (5 tsp) of sugar
    – A few drops of vanilla or other flavoring

    2. Fill the larger bag half full with ice.
    3. Sprinkle 100mL (1/2 cup) of rock or coarse salt over the ice.
    4. Seal and place the small bag inside the larger one surrounded by the ice mixture. Seal the big bag.
    5. Time one-minute intervals. At the end of each minute, flip the bag over on the other side. Repeat the “flippings” about 10 times.
    6. After 10 times, begin flipping the bag over every 30 seconds for 5 minutes.
    7. Check to see if your ice cream is the right consistency. If it is not, continue flipping the bag at 30-second intervals for another 5 minutes.

    Pay particular attention to step 3, which is highlighted in a cyan color. This will be the focus of our discussion.

    While making ice cream, heat must be removed from the water in the cream to solidify. However, because of all the particles ice cream contains, the temperature must drop below 0 degrees Celsius in order for the mixture to become solid. Therefore, pure ice cannot be used to freeze ice cream, because it’s freezing point is 0 degrees Celsius, which is higher than the freezing point of ice cream (which is around -3 degrees Celsius).

    A solution to this problem is the addition of rock salt to ice, which lowers its freezing point. This is because energy is required to form the hydrogen bonds necessary for ice, and when impurities such as salt are added to water or ice, they prevent water from making hydrogen bonds and achieving solidity. Hence, the water must become even colder before it freezes. So how does this affect the immediate temperature of the ice? Adding salt to ice causes the temperature of the brine solution to decrease dramatically, because as the ice melts, the “heat” of the ice mass is preserved by lowering the temperature (this is called latent heat). As a result, the temperature is lowered to below the freezing point of pure water, and the solution can be used to freeze ice cream.

    When the cream in ice cream cools down and loses its heat to the salt and ice solution, ice crystals begins to form. Water freezes out of a solution in its pure form as ice. In a sugar solution such as ice cream, the initial freezing point of the solution is lower than 0 degrees Celsius due to these dissolved sugars and the impure particles in the ice cream, as I mentioned before. As ice crystallization begins and water freezes out in its pure form, the concentrations of the remaining solution of sugar is increased due to this removal of water, and hence the freezing point of the ice cream is further lowered. This process is shown here:

    This process of freeze concentration continues to very low temperatures. Even at the typical ice cream serving temperature of -16 degrees Celsius, only about 72% of the water is frozen. The rest remains as a very concentrated sugar solution.

    Thus when temperature is plotted against % of water frozen, we get the phase diagram shown below:

    This helps to give ice cream its ability to be scooped and chewed at freezer temperatures. Air content also contributes to this ability.

    Still find the concept of Freezing Point Depression difficult to comprehend? Check out the video below for a live demonstration and explanation of the concept with ice cream:

    Author: Jamie Lee



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    How to Bake a Cookie – In Terms of Chemistry

    Baking a cookie is pretty simple. You can either buy pre-made cookie dough and just place little balls of the dough in the oven, or you can make cookie dough from scratch then bake it. However, did you ever look at baking a cookie through a chemistry aspect? Believe it or not, a series of chemical reactions takes place while baking a cookie!

    Here is a recipe for chocolate chip cookies, in terms of both “English” and chemistry.


    • 3/4 cup sugar – sucrose
    • 3/4 cup packed brown sugar – sucrose and flavoring
    • 1 cup butter – fat
    • 1 large egg – emulsifier, albumin, fat, protein
    • 2 1/4 cups-all purpose flour – gluten
    • 1 teaspoon baking soda – sodium bicarbonate (NaHCO3), serves as a base
    • 1/2 teaspoon salt – NaCl
    • 2 cups semi-sweet chocolate chips – flavoring


    1. Preheat oven to 375 degrees.  Mix sugar, brown sugar, butter, vanilla and eggs in a large bowl.

    • There is no chemical reaction that occurs while mixing these ingredients. There are only physical changes, no chemical changes.

    Stir in flour, baking soda, and salt.

    • As stated in the previous post, flour forms gluten. Gluten makes the mixture more elastic, so the flour is added later in the process to keep these gluten complexes small. This is why the dough is able to break apart. If it were to be elastic, then it would just end in a messy, goo-ey mess, and it would harder to form smaller pieces from the dough. The baking soda serves as a leavening agent to soften the mixture.

    3. Stir in chocolate chips.

    • The chocolate chips do not have a significance in terms of a chemical reaction; they simply serve as an ingredient to add flavor to the cookie.

    4. Drop dough by rounded tablespoonfuls 2 inches apart onto ungreased cookie sheet.

    • The size of the dough is not just important in terms of preference. The size of the dough determines the results of the cookie. Carbon dioxide (CO2) bubbles form throughout the entire cookie, but only the outer edge of the cookies caramelize.

    5. Bake 8 to 10 minutes or until the cookies become light brown.

    • While baking, the heat allows for the sucrose (sugar) to break down into glucose and fructose. This causes a polymer chain which allows for the cookie to have a light brown, shiny crust. When the sodium bicarbonate (baking soda) absorbs heat, a chemical reaction occurs – 2NaHCO3 –> Na2CO3 + H2O + CO2. The carbon dioxide from the reaction can be seen from the bubbles in the cookies. The NaCl (salt) slows down the production of the carbon dioxide and prevents these bubbles from becoming big. The fat (butter) controls the formation of gluten from the flour, which contributes to its lighter texture. It also serves a role in the taste of the cookie. The emulsifier, or fat and protein from the egg yolk hold the dough together (the main purpose of an emulsifier), while the albumin from the egg whites support the bubbles. 

    6. The centers will be soft.  Let cool completely then remove from cookie sheet.

    7. Remove from cookie sheet and place on wire rack or on a table to finish cooling.

    • The cooling allows for the completion of the caramelization process (this gives it the brown-ish color), and it also allows for the structure developed by both the gluten and the egg to set.

    Notice how some of the reactions relate back to our previous posts? All these reactions seem to be common in baking! Check back later to see any additional chemistry that is involved in baking or any other reactions that occur in baking! (:

    Author: Erica Rowane Bautista


    * This recipe was reworded and taken from this website. Information was also taken from our previous posts.

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    What is in Cake Mix?

    To my fellow bakers out there who cannot even manage to whip up a brownie mix without producing one that resembles a pile of muck, I feel your pain. Our lack of efficiency with an oven, therefore, should justify our clandestine storage of “Betty Crocker” baking mixes near the back of the cupboard. While aggregating the cake mix with the necessary adjuncts (i.e. water/buttermilk, eggs, vegetable oil, etc.) has become routine for us inept bakers, have you ever considered what exactly composes such cake mixes? We are, after all, only familiar with the delectable desserts that our ovens manage to conjure from solely water, eggs, oil, and a mysterious powder mixture, and rarely question the label on the mix box that reads, “Make decadent, bakery-quality cakes in your home oven!”

    The components of and chemistry behind packaged cake mix are far from complex. Among the cake mix ingredients include, and are not limited to, flour, sugar, leavening, shortening, emulsifiers, colorings, and flavorings. Below you will find the purpose of and chemistry behind each of these components:

    Flour: When combined with water, the mixture forms gluten, a complex protein that allows for the formation and maintenance of gas bubbles, which provides the mix with its malleability.

    Sugar: In addition to sweetening baked goods, sugar allows baked treats to maintain their moisture, thus increasing shelf life. Sugar also influences yeast growth; while a sufficient quantity of sugar is necessary to instigate yeast growth, superfluous sugar may render the yeast growth process inactive.


    Leavening:  What are the two most common leavening agents? Both baking soda and baking powder are used for cake batters to rise. Simply put, leaveners raise baked goods by expanding the gas bubbles produced by the creaming of ingredients. Baking powder constitutes baking soda, at least one acid salt, and cornstarch to take in all moisture and prevent a reaction from initiating until another liquid is poured in with the batter. When used in cake batter, baking powder reacts in two stages, with the first occurring when the powder is added to moistened batter and an acid salt reacts with the baking soda to form carbon dioxide gas. Once the batter is in the oven, the imposed heat forces the gas bubbles to enlarge and the batter to rise. On the other hand, baking soda, or sodium bicarbonate, leaves most of the leavening to baking powder when both are required in a recipe.



    Shortening: Shortenings include the fats or oils of vegetable or animal origin included in baked goods to create a soft, smooth crumb and tenderness. Most shortenings are quite consistent in chemical composition and consist of the following in varying ratios:

    • STEARIN—a naturally-occurring, hard fat of animal origin
    • PALMITIN—a fat, secured from both animal and vegetable sources
    • OLEIN—an oil secured from both animal and vegetable sources
    • LINOLIN—an oil present in cottonseed oil


    Emulsifier: Emulsifiers fix the fats and liquids together and contribute to the moistness of baked goods. The most common of emulsifiers is soy lecithin.

    Check back later for more about the chemistry of baking! (:

    Author: Carrie Xu




    Caramelization is the process of sugars breaking down. This is often used as a general term to describe the Maillard Reaction. However, these two browning processes are very different. The Maillard Reaction is the break down of sugars in the presence of proteins, therefore it contributes to the browning and flavoring of bread crusts.

    Simply speaking, caramelization is the process of removal of water from a sugar (such as sucrose or glucose) followed by isomerization and polymerisation. In reality the caramelization process is a complex series of chemical reactions, which is still poorly understood.

    Below is a table listing the Stages of Caramelization.

    Caramelization Stages Table

    Caramelization is sensitive to its chemical surroundings. For example, the level of acidity (pH) must be controlled or else the reaction rate may be altered. Caramelization usually occurs slowest when when the acidity is near neutral (pH of 7), and it is accelerated under both acidic and alkaline conditions.The different stages of caramel production all have distinct names based on the characteristics of the product. “Thread” indicates the fact that sugar can be spun into soft or hard threads, “ball” indicates that sugar can easily be molded into a proper shape, and “crack” indicates that the sugar will hard after cooling (and crack when it is broken).

    The animated video below expands more on The Maillard Reaction and Caramelization:

    Things to keep in mind while watching the video:

    • What is the difference between Enzymatic and Non-Enzymatic Browning Reactions?
    • How does temperature affect the Maillard Reaction?
    • What are some desirable and undesirable affects for all three reactions?
    • What is the difference between the Maillard Reaction and Caramelization?
    • Which reactions occur in baked goods?

    Look forward to our future posts discussing the chemistry of baking!

    Author: Jamie Lee


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    The Maillard Reaction

    This year marks the 100 year anniversary of the discovery of the Maillard Reaction – a key reaction in food science. Several hundred scientists met in the small French city of Nancy to attend a conference that was held to celebrate the anniversary of this great discovery. The scientists gathered together to present scientific papers related to this chemical reaction. So, how did this reaction come about?

    It began 1912, when Louis-Camille Maillard conducted experiments based on the reasoning behind the production of carbon dioxide and change of color of raw ingredients when heated. He believed this reasoning would pave a new path for the world of medicine and diabetes, and did not bother to consider the importance of this discovery for food. Obviously, he was wrong, as his discovery proved to be a major milestone for food chemistry. The Maillard Reaction takes place in many cooking processes, and it is possibly the most favored and flavored chemical reaction.  Now, you may be wondering…what exactly is the Maillard Reaction and why is it so important?

    The Maillard Reaction is actually a series of many complex reactions between reducing sugars (carbohydrates) and an amino acid (the basic foundation of all proteins). The Maillard Reaction is responsible for the browning of toast, nuts, hash browns, beer, roasted meat, etc. The glazing of milk and egg ingredients on baked goods lead to the Maillard reaction on the crusts of the baked goods, allowing for a browning on the surfaces.

    The reaction takes place in several steps:

    Step 1: A reducing sugar (such as glucose) reacts with an amino acid to form a product called the Amadori compound.

    “The Amadori compounds easily isomerise into three different structures that can react differently in the following steps. As in food generally over 5 different reactive sugars and 20 reactive amino acids are present, only the first step theoretically already results in over 100 different reaction products.”

    The size of the reducing sugar affects the rate of reaction. Larger reducing sugars generally conduct a slower reaction and a lighter resulting color, while smaller reducing sugars generate an opposite affect. In addition, there are certain types of reducing sugars (such as sugar alcohols or polyols) that do not take place in the Maillard reaction. In other words, baked goods using these products will not be affected in a change of color.

    Step 2: Depending on the isomer of the Amadori compound, the amino acid can either be completely removed, or the isomer can be rearranged. This rearrangement is the main contributing factor towards the browning or change of color of the food during the reaction.

    Depending on the rearrangement, there are three different possible pathways:

    1. dehydration reactions
    2. fission – production of short chain hydrolytic products
    3. strecker degradations – involves amino acids or the condensation to adols

    The three different pathways usually end in the ultimate result of mixtures, which include flavour compounds and the brown pigments, melanoidins – the pigments often found in brown-colored foods.

    This reaction usually takes place at high temperatures, so processes such as frying, roasting, grilling, and baking are heavily dependent on the Maillard Reaction. However, high temperatures are not the only contributing factor towards the reaction. There’s also:

    • time
    • water activity
    • pH level – (example: a higher pH value results in a faster Maillard reaction for a pretzel, giving a saltier taste and an even darker color of brown)
    • presence of oxygen
    • types of amino acids

    Table 1 displays the effects of these conditions on the Maillard Reaction.

    Table 1

    These contributing factors make the already-complex Maillard Reaction even more complicated, as a small difference can affect the taste, aroma, and color of the product. These factors along with the reaction can also form acrylamide and furans, dangerous substances that could potentially cause cancer. Therefore, it is important to note the amino acids and contributing factors when using cooking methods involving the Maillard Reaction, as a small alteration can yield a completely different product.

    Who knew a daily activity could contain a lot of chemistry with such complicated explanations?

    The video above demonstrates the Maillard Reaction, while discussing caramelization – another type of nonenzymatic browning reaction.  This completely different process may be discussed later.

    Author: Erica Rowane Bautista

    Sources used (also includes sources of pictures):