Introduction

We are all aware that sugar provides sweetness to our food. However, they offer other important functions that you should know. Read this article to learn more about the top functional properties of sugar.

Sugar has several Sugars are either monosaccharides or disaccharides. Monosaccharides are carbohydrates with only one sugar unit. For example, glucose, fructose and galactose. Disaccharides are sugars with two sugar units, for example sucrose, lactose and maltose.

Another name for sucrose is table sugar. It is the regular white or brown sugar that we use at home to sweeten drinks or to bake with. Sucrose is made from either sugar beet or sugarcane. It consists of a glucose and a fructose unit. Lactose is the sugar found in milk. It is made up of galactose and glucose. Some people cannot metabolize lactose because they lack the enzyme lactase to digest it. These people are referred to as lactose-intolerant. They may experience symptoms of bloating, diarrhea, and abdominal pain whenever they consume dairy products.

Maltose is known as malt sugar. It is derived from barley, and consist of two glucose units. Maltose is considered by some consumers to be a healthier sugar than sucrose because it has a much lower glycemic index; meaning that it digests more slowly. This is good for diabetic patients who require a slower release of glucose to the blood.

Sugars have various functional properties that are utilized by Food Scientists to meet consumer needs. Important functional properties to be familiar with include: sweetness, color, flavor, texture, preservative, and fermentation. Read more to explore the functional properties of sugars.

Sweetness

Sugars have different degrees of sweetness depending on their chemical structure. Sucrose is generally used as a standard for sweetness. It has a relative sweetness of 100. However, it is not the sweetest sugar. Fructose is much sweeter, reaching up to a relative sweetness 160. Glucose and lactose on the other hand, are not very sweet. Glucose has a relative sweetness of 80 and lactose only 20. That explains why milk is not sweet, even though it contains up to 5% lactose.

Color and Flavor

Sugars may be reducing and non-reducing. You’ll have a better understanding of the chemistry of reducing sugars after you have done a class in organic or food chemistry. But essentially what you need to know at this point is that reducing sugars can react chemically with proteins in foods to produce a brown color, along with flavor compounds. We call this chemical reaction  maillard reaction or maillard browning. For example, when you bake bread or grill meat, the dark color crust or the grill marks that you see on the surface is as a result of maillard reaction. All monosaccharides are reducing sugars. However, only some disaccharides are reducing sugars. Maltose and lactose are examples of disaccharides that are reducing sugars. Sucrose however, is not a reducing sugar. Any browning that is caused by sucrose is not because of maillard reaction, but is attributed to caramelization. This is a different type of reaction that does not need the presence of proteins. Once you heat sugar to a very high temperature, for example heating sucrose to 350 degrees Fahrenheit; it undergoes dehydration, decomposition and polymerization to form new color and flavor by-products.

Texture

Sugars adds viscosity, consistency or body to liquid foods such as juices and syrups. Sugars have the ability to absorb water (hygroscopic). This property imparts moistness to products such as breads and cakes. In ice-cream, sugars impart softness and creaminess by lowering the freezing point of water and preventing the ice-cream from freezing right through. Freezing right through would make ice-cream rock-hard.

Preservation

Sugars are natural preservatives. Sugars bind water in solution and dehydrate microorganisms, preventing them from growing.

Fermentation

Sugars can be fermented by yeast to produce carbon dioxide and flavor by-products. Common examples of fermentation is seen in the production of beer, wine and bread. In the case of bread, in addition to the production of flavors, fermentation of sugars cause bread to rise, giving volume and a unique crumb texture.  

Reference: Potter, N. N. & Hotchkiss J. H. (1998). Food Science, 5th edition. New York, NY: Springer Science+Business Media LLC.

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Courtney Simons
Courtney Simons
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Courtney Simons is a food science professor. He holds a BS degree in food science and a Ph.D. in cereal science from North Dakota State University.