Nowadays, sugar has become more and more common in our daily life. Does anyone know what is the sugar chemistry behind the making candy? Well, let me briefly explain how candy is made and what are the different types of candy we have. There are various types of candy and they are all classified under crystalline candy and non-crystalline candy, non-crystalline candy is also known as amorphous. For common types of sugar, it is always first extracting sugar cane juice which is a type of syrup pressed from sugar canes, the term “juice” is also misleading since it is not a fruit or a vegetable. The examples of crystalline candy are such as fudge, nougat, and fondant which are generally soft, liquid-like and can melt in your mouth while the examples of non-crystalline candy are lollipops, candy canes and caramel which is hard and fragile. From there onwards, this is how numerous types of sugar are made. Alter different conditions or processes of this syrup such as its method of crystallizing, solidifying and different levels of molasses which can create a huge variety of sugar. This will open many different types of sugars which have different crystals which all has its own unique properties and flavours, enabling us to make a variety of consumables. In addition, the wetness and the flavour of the candy can be affected even before and after being heated or the addition of molasses to the crystals, there are also many different types of sugar which are only used in food production companies and cannot be found in supermarkets. “Now, let us find out more about the sugar. The specific name of sugar is called sucrose which is disaccharide. It is made up of two monomers, glucose, and fructose. In order to get different types of candy, you are required to add different ingredient according to the recipe. Ingredients added rate of cooking, the concentration of sugar, conditions of cooling, and degree of agitation all can influence whether a candy is crystalline or non-crystalline.” (Walter & Beathard, 2011, p. 231). For example, different temperatures of the heating process will affect different states of sugar and this is how different types of candy are made. The difference in crystallization will even affect on different textures of the candy as well. Then the sugar mixture will have to cool down, and during this period is very important because it will determine if the candy is hard (non-crystalline candy) or soft (crystalline candy).
Crystalline candies contain sucrose crystals in their final stage; the sucrose molecules line up and form large lattices. The key factor in making crystalline candies is slowly cooling the sugar solution without any stirring to prevent the crystals formation from being disrupted. To make most types of candies , you should always start by adding sugar to boiling water. As a result, sugar syrup is formed, which you can cool it down by removing it from any heat sources.
Crystalline candy, has a lower boiling point compared to non-crystalline candy, as crystalline candy has a lower concentration of sugar. Thus, the sucrose solution is boiled at a lower temperature. The texture of a crystalline candy is pliable and smooth. This is because crystalline candies consist of many small crystals of sucrose molecules. The key factor in the formation of crystalline candy is consistent beating, which prevents the accumulation of large crystals. The combination of agitation and the sticky solution result in crystallization into small aggregates, which gives the confectionary a smooth texture.
Fondant, an example of a crystalline candy, is the base of most chocolate-covered and crystallized crèmes. Fondant can be made by mechanically beating a solution supersaturated with sucrose. When water is heated to its boiling point, more than twice as much of sugar will dissolve in water than at room temperature. When the sucrose is dissolved, the solution is left to cool. If the solution is undisturbed while cooling down, the sugar will remain dissolved in a supersaturated solution and then stirred vigorously, until tiny crystals are formed. As a result, an opaque, white, smooth textured fondant is formed.
The best way to make fondant is made by boiling water and sugar together until it forms a soft ball. Sometimes, cream of tartar is added for extra stability. Once is done, the ball is then thinned out more with corn syrup to make poured fondant or rolled fondant.
Fondant can be categorized into two types: poured and rolled fondants. Poured fondant is a sweet paste which is usually used as an icing or filling for cakes and other pastries. Poured fondant is made of mainly sugar, water and corn syrup.
Rolled fondant, unlike poured fondant, is rolled out into sheets that can be coloured and used to decorate cakes. Like poured fondant, rolled fondant is also made with sugar, water and corn syrup. Gelatin or glycerin is added in order to make the fondant a more pliable dough.
Fudge is also another example of another crystalline candy. Most microcrystals that are found in fudge are what gives it its firm surface. The crystals are sufficiently little, in any case, that they don’t feel grainy on your tongue, however, they feel smooth.
While you ultimately want crystals to form, it’s very critical that they don’t shape too soon. The way to a fruitful, non-grainy fudge is in the cooling, not the cooking. To make fudge, the ingredients have to be heated to a soft-ball stage, or 234° F. Then, enable it to cool undisturbed to around 110° F. It is advisable to not to stir during this cooling phase to prevent seed crystals from forming too soon.
A seed crystal is a surface that sucrose particles can attach themselves to and it could be a couple of sucrose atoms stuck together,a piece of dust or even with a little air bubble. Once a seed crystal is formed, it grows bigger in size as the fudge cools. A great amount of enormous crystals in the fudge makes it grainy.
By giving the fudge a chance to cool without mixing, the formation of seed crystals is prevented. Blending would enable sucrose atoms “to find” each other and begin forming crystals. Blending likewise presents air, tidy, and little-dried particles from the wall of the pan—every single potential seed for crystal arrangement.
At the point when the fudge has cooled down to around 110° F, you need to begin the crystallization procedure. You begin to mix and continue blending, until the point the confection becomes thick. The more you mix, the more crystal seeds you get. Yet, rather than getting a couple of enormous crystals, you will get plenty of little crystals, which make a thick and smooth treat.
Another example for crystalline candy is rock candy. To make rock candy, we use more sugar than it could dissolve in water at room temperature. For instance, we can add three cups of sugar into one cup of water. In order to allow all the sugar to dissolve, we have to boil the water to increase the temperature. By increasing the temperature, the dissolving process will simultaneously increase. The solution is heated until no more sugar can dissolve. Then, the sugary solution is left to cool down for several days to allow huge crystals of sugar to form.
So what happens when the solution finally cools down? Once it cools down, it becomes a supersaturated solution. A supersaturated solution is unstable as it contains more solute. As the temperature decrease, sugar crystals are formed. This crystallization process can be explained by the Le Châtelier’s principle; which states that if a system is shifted away from its equilibrium, the system will respond to restore its equilibrium by reacting in opposition to the shift. Thus, a decrease in temperature causes a system to generate energy, to bring the temperature up. This is because when the chemical bonds are formed, energy is released. Therefore, more sucrose molecules will join the crystal in an attempt to increase the temperature. This explains the formation of crystals when the temperature decreases. In short, the lower the temperature, the more sucrose molecules join the sugar crystals, and that is how rock candy is made.
Non-crystalline candies are also called as hard candies. Non-crystalline candy is made from sugar which has the property to form non-crystalline or the ‘glass’ form of candy. The examples of non-crystalline candies are hard candies, caramel and marshmallows.
Generally, to make non-crystalline candy, sugar is dissolved in water and boiled at high temperature. When the sugar solution concentration becomes high, supersaturation (a state where a solution contains higher dissolved solute than could be dissolved by the solvent usually) continues upon the cooling process. The solution becomes a plastic or glass form from further cooling and then becomes hard and transparent. In general, non-crystalline candy does not contain or in the form of sugar crystals. They usually have chewy or brittle texture.
The main ingredients of making non-crystalline candy are sucrose or sucrose solution, glucose and sometimes the flavouring and colouring agents. The ratio of sucrose (sugar) to glucose is usually 7:3. Glucose is used as the stabilizer to make the mixture easier to be formed and moulded. It also helps to prevent water absorption of candy.
Sucrose is dissolved in water to form sugar solution. The sugar solution is boiled at high temperature (around 146-154°C) until it starts to evaporate. The solution will dissolve into its molten form, resulting in a very saturated sugar solution formed (the sugar concentration is about 99%). At this point, the saturated sugar solution is considered as a supersaturated solution. The supersaturated solution is very unstable, where any form of disturbance such as stirring or whisking, will cause the sugar solution to crystallize.
To prevent the crystallization of sugar, invert sugar or corn syrup is added to the solution. Corn syrup contains complex saccharides, which is starch to increase the solubility of sugar solution and retard the crystallization. When the mixture is heated, the starch in corn syrup will break down into glucose molecules. The chemical equation for this process is (C6H12O6)n starch + nH2O water ? nC6H12O6 glucose + C6H12O6 glucose. The glucose molecules which are smaller than the sucrose molecules in the sugar solution weaken the crystallization in the sucrose molecules, which then interfere the development of sugar crystals.
The sugar solution is poured onto a cooling table and let to cool down. During cooling, the sugar solution starts to become more solid or into “plastic-like” form which is flexible. At this stage, flavoring and coloring agents can be added. In certain candy, citric acid is added to the candy to prevent crystallization of sucrose by the hydrolysis of sucrose, which it will break down into its basic components – glucose and fructose. Finally, the sugary mass is aerated, usually by rolling or folding it so that it is shaped, cools down faster and becomes more solid.
To make caramel, sugar, butter, and water are needed. Sugar, sucrose is dissolved in a small amount of water and heated at 170 °C. When heated, the sucrose will break down into glucose and fructose. The reaction is called sucrose conversion and the chemical equation for this reaction is C12H22O11 (sucrose) + H2O (water) + heat ? C6H12O6 (glucose) + C6H12O6 (fructose).
Next, caramelization reacts with the glucose and fructose in the sugar solution. The glucose and fructose molecules undergo condensation, in the other words, dehydration. The molecules start to bond with each other as they remove water. The hydroxyl group of one molecule bond with the hydrogen atom of another molecule forming water molecule and leave as water.
Caramelization is also known as the procedure of making caramel from sucrose. At the beginning of caramelization process, diacetyl is formed. Diacetyl, C4H6O2, is a byproduct of fermentation, and usually added margarine to give the food a buttery texture. The diacetyl gives the caramel a buttery or butterscotch-like taste. However, the caramelization of other sugars such as maltose and galactose are different in the amount of heat required for caramelization.
Marshmallows are also a non-crystalline candy regardless of their texture, it is because they are not grainy and bigger in size, which is usually an indicated rule for non-crystalline candy. To make marshmallows, sucrose, water and gelatin are needed. Firstly, gelatin is dissolved in cold water to let the long protein fibre of it to loosen and spread out. The sugar is dissolved in water and boiled until it becomes a soft ball like texture. Then, the sugar solution or syrup is mixed with the gelatin and beaten into triple of its initial size. During this process, the molecular bond in gelatin is dissolved by the heat in the sugar.
Next, egg white is beaten into whipped form. The whipped form egg white and vanilla are added to the mixture of sugar and gelatin. Lastly, the cream-like mixture is poured and spread into cooling pan and let to cool down. When the gelatin mixture is cooled down, the protein bonds reform. The protein bonds will combine with the ingredients, the egg white (which is also a protein) and vanilla to form a bouncy texture.