The Chemistry of Margarine

Introduction

YouTube Video



Margarine is a butter-like spread that many consumers use on a daily basis. Although it is derived from a variety of plant and vegetable oils, through a process called hydrogenation these liquid oils become the loved spread. However margarine’s ingredients are not necessarily this black and white. To meet modern health concerns, trans fat free margarine is also created through another process called enzyme interesterification. Although it originally was a simple combination of hydrogenated animal fats, margarine as evolved into a spread of great diversity in its nutrition and manufacturing process. Since its invention nearly 150 years ago, this spread has become a healthier alternative to butter, a notoriously unhealthy spread. However, in order to make the correct decision for one’s health, they must understand the key differences between ordinary margarines. Although these differences may seem subtle, the way in which the body processes the different ingredients has critical implications on one’s health. However, once one understands how to read a nutrition label for the “good” and “bad” fats, making decisions on which products to buy is much simpler.

I chose to research the chemistry of margarine because it is something I consume on a daily basis and I was curious about its content. I never understood why margarine was “healthier” than butter. I was also curious about why the consistency of margarine seems softer than butter when they are both chilled. Margarine is filled with chemistry from the way is created to the final product they put in the tub. It is important for consumers to understand the content of these products so that they can make the healthiest decisions for themselves and their families.

Margarine is consumed on a wide basis, from the spread on one’s toast to a wide variety of baked goods and pastries. It is critical that the consumer takes responsibility for educated him or herself on the content of these spreads. Having the ability to read and understand a nutrition label is a crucial skill that can have a large impact on people’s lives. Whether one realizes it or not, margarine plays a key role in many of the food products they consume. Once this understanding is achieved, its importance to the modern diet is clear.



Composition of ...

  • Hydrogenated Oleic Fatty Acid: CH3CH3 (in margarines containing trans fat)

  • Water: H2O

  • Lactic Acid: C3H6O3

  • Oleic Fatty Acid: H2C=CH2 + H2

  • Potassium Sorbate: C6H7KO2

  • Salt: NaCl

  • Soy Lecithin: Contains 3 phospholipids: phosphatidylcholine (C10H18NO8PR2), phosphatidylethanolamine (C7H12NO8PR2) and phosphatidylinositol-C47H83O13P

  • beta-Carotene: C40H56


Main Chemicals, Compounds, Components

  • Water (H2O): High on the ingredients list of most margarines is water, which may come as a surprise to many. Why?: because water is liquid at room temperature, clear, and tasteless, a sharp contrast to the spread. Water is one of the most abundant compounds on Earth, made of two of the most common elements, hydrogen and oxygen. Water composes anywhere from 55-78% of the human body and covers 71% of the Earth’s surface. With the chemical formula H2O, water is composed of two hydrogen molecules around one oxygen molecule. Since water is a polar molecule, the hydrogen atoms carry a slightly positive while the oxygen atoms carry a slightly negative charge. This also means that while some molecules mix very well with water, others do not. Molecules that mix well with water are called hydrophilic while water repelling molecules are called hydrophobic. Water is a liquid at room temperature and must be mixed with other ingredients, like fat, to solidify.

  • Hydrogenated Oils (CH3CH): In order to become spreadable, liquid hydrogenated oils undergo a chemical reaction. In most margarines, a variety of oils are present including soybean, cottonseed, and palm oil just to name a few. Through a process called hydrogenation, these liquid oils fill carbon double bonds with hydrogen single bonds. This results in a spread that will remain solid at room temperature. One simple hydrogenation reaction can be shown by the chemical H2C=CH2 + H2 which yields H3 after hydrogenation.  Due to this reaction, nutrition labels on margarine show a low saturated fat content; however, when oil undergoes hydrogenation, they become trans fats. Consumption of trans fats raises bad cholesterol and lowers good cholesterol which has been linked to numerous health issues; these correlations have cautioned consumers to stay away from margarine. However, not all margarines are made with hydrogenated oils which is why it is important to read food labels.


Chemistry's Role

  • Emulsification to Combine Oil and Water: Two of the first ingredients in margarine are water and oil. These liquids are immiscible; this because water is a polar molecule, meaning that the charges are asymmetrically shared, and oil is a nonpolar molecule, meaning the charge of the molecule is equally distributed. Since water molecule’s charge is unequally distributed, the hydrogen atoms carry a more positive charge and the oxygen atoms carry a more negative charge. This can be attributed to the higher electronegativity of oxygen compared to its hydrogen counterparts, which carry a low electronegativity. Because of this unequal sharing, water molecules tend to want to make a formation together, which is why water has a high surface tension. Therefore, when one adds uncharged oil to the the water, the water tends to “push” it away because it would rather associate with itself. In a substance like margarine, whose first ingredients include water and oil, it is important to prevent separation. To eliminate this, emulsifiers must be added to the mixture; for margarine, the most common emulsifier is lecithin. All emulsifiers have two ends: a hydrophilic end, or water loving, and a hydrophobic end, water repelling. Hydrophilic ends attract the water and hydrophobic ends attract the oil; therefore, when an emulsion is evenly distributed in a spread like margarine, the water and oil do not separate. Emulsifiers have other roles in margarine as well. For example, emulsifiers in frying margarine prevent splattering; furthermore, in whipping margarine, they improve its ability to cream.

  • Hydrogenation of Oils: Vegetable oils, which are used in the production of margarine, are polyunsaturated fats, meaning that they contain many carbon double bonds. By contrast, butter contains saturated fat which is linked to diseases like cardiovascular diseases; therefore, most consider vegetable oil to be a healthy fat. However, chemists faced a problem: vegetables oils, like other unsaturated fats, are liquid at room temperature. In order to give these oils the consistency of margarine, chemists put them through a process called hydrogenation. During hydrogenation, the oil is heated to about 150 degrees Celsius and passed through a nickel catalyst. In these conditions, the oil reacts with the hydrogen, meaning that some of the carbon double bonds are converted to hydrogen single bonds. Since only some of the carbon double bonds are replaced with hydrogen, this is called partial hydrogenation. Problem solved! Not so fast though. When this oil undergoes hydrogenation, a simple but vital change occurs: cis bonds become trans bonds. Cis, meaning same, refers to the the H2C and the CH2: while in unsaturated fats, these chemicals are on the same side of the molecule between a carbon double bond while facing single hydrogen atoms, trans fats flip this configuration. In a trans fat, the H2C and the CH2 are diagonal from each other. This may seem like a minor and insignificant change; however, when trans fats are processed, they raise bad cholesterol and lower good cholesterol which can lead to heart attacks and strokes.

  • Enzyme Interesterification to create Margarine without Trans-fat: So, if margarine can be trans fat free, how does it achieve its texture? Fats are triglycerides, meaning they contain three fatty acids around a glycerol. In a saturated fat, all three of the fatty acids are filled with hydrogen and in an unsaturated fat, carbon double bonds are present. Through the process of interesterification, one or two of the three unsaturated fatty acids in the triglyceride are replaced with saturated fatty acid. Makers of this margarine combine liquid unsaturated fat, solid saturated fat, like glyceryl tristearate, and an enzyme called lipase. The lipase disconnects the fatty acids from the glycerol and when they re-attach, they do so randomly so that some of the side chains are saturated and some are unsaturated. This results in a “partially hydrogenated” fat. Many tub margarines are made through this process. This is why, generally, tub margarines are healthier than stick margarines.


Background Research

It was in 1813 that Michel Eugene Chevreul found a pearly white colored acid that he named margaric acid; although it was merely a combination of stearic acid and palmitic acid, this eventually became the name of one of the most widely consumed spreads. However, the real credit belongs to none other than Emperor Napoleon III of France; in 1869, he proposed a challenge: to create a butter alternative that he could offer to armed forces and lower classes. This was taken up by French chemist, Hippolyte Mège-Mourièsy, who created the first spread he called oleomargarine. Although this product did not succeed on a commercial level in France, in 1871, the patent was sold to a Dutch company, Jergens, who suggested that consumers would find the spread more appealing if it were dyed yellow. The same year, the first factory, Benedict Klein Margarinewerke, produced oleomargarine in Germany. Also in 1871, margarine made its way to the United States, which was typically a combination of animal and vegetable fats.

Margarine was not always very popular. Naturally, their butter making counterparts were not ecstatic that a cheaper alternative was suddenly available; they took a legal path of resistance, convincing legislators to tax margarine, and by the 1930’s, margarine that was colored artificially was considered contraband in more than 30 states. Some states even forced manufacturers to dye the margarine pink, making the spread even more unappealing. However, there were loopholes to even these restrictions; in 1951, the W.E. Dennison company received a patent to include a packet of yellow food dye with the margarine that could be kneaded into the spread for a more butter-like appearance. Following the outbreak of World War II created a shortage in animal fats which eventually led to the first margarine containing only vegetable oils. Margarine also increased in popularity during this time when a shortage of dairy stimulated the switch. The legislature on margarine was also repealed during this time, including many state’s artificial color ban and the tax, which was repealed in 1950. For the next 50 years, margarine underwent many changes, evolving into the spread we know today. However, modern margarines have been tweaked to meet the demands of the culture; for example, hydrogenated fats have been reduced to lower the amount of trans fat. Furthermore, brands like “I Can’t Believe It’s Not Butter” have emerged, creating a competitive market.

Today, margarine is a highly regarded butter substitute  notorious as a healthier alternative to an iconically unhealthy food. However, like many products of the 21st century, misleading packaging can fool consumers who fail to investigate this product. The question most people want answered is actually quite simple: which spread is healthier? The answer is not nearly as straightforward as one may imagine. The main nutritional difference between butter and margarine is the fat they contain; while butter is high in saturated fat, margarine contains trans fat, which raises bad cholesterol. Generally, most doctors recommend their patients to eliminate trans fats because they are attributed to high cholesterol; therefore, butter is better, right? However some margarines, especially modern tub margarines, are trans fat free; therefore, these are healthier than butter. In the end, there is only one sure way to choose a spread: checking the food label for trans fat.

Main ingredients in margarine include water, vegetable oil, skim milk, salt, and emulsifiers. However, these ingredients can vary from spread to spread. However, these simple ingredients must undergo many reactions in order to become the familiar spread. For one, the oil, or oleic acid, must become hydrogenated oleic acid through a process called hydrogenation. Through this process, the oil is heated and passes through a nickel catalyst and hydrogen. This partially hydrogenated oil is then suspended in salt water. Hydrogenation is the most important chemical reaction; without it, margarine, like the oil it is composed of, would not be solid at room temperature. However, the process of hydrogenation is also the downfall to margarine, because it creates the trans bonds, rather than cis bonds that are unhealthy to the body. While the ingredients in margarine vary, one typical tub margarine contains liquid oil, water, various types of oil which are hydrogenated in margarine containing trans fat (soybean, cottonseed, palm, etc.), buttermilk, distilled monoglycerides, soy lecithin, potassium sorbate, lactic acid, and beta carotene. Stick margarine generally contains less water and more hydrogenated oil, accounting for its high trans fat content. Margarine is an extremely versatile and well-known product in modern life. Although its origin may be unusual, margarine became a widely used spread and a product that is used by many daily.



Resources

About the Author

Paloma Whitworth is a junior at Billings Senior High. She enjoys giving tours at Moss Mansion, running and leading her cross country team on the Go Team, playing viola and piano, and serving her community through Interact club, Key club, STEM society, Student Council, environmental club, and Senior Advocates. She also participates in the Platinum program and aims to complete a capstone project on composting before the end of her Senior year. She hopes to attend college on the west coast and eventually attend medical school to become a pediatrician.








Comments