Process of caramelization

Caramelization is what happens when any sugar is heated to the point that the molecules undergo chemical reactions with oxygen in the air and with each other – the molecules either break apart into smaller molecules, or combine with one another to make larger molecules. The result is a very complex, brown colored mixture that normally call caramel.

Caramelization occurs in food, when food surfaces are heated strongly, e.g. the baking and roasting processes, the processing of foods with high sugar content such as jams and certain fruit juices, or in wine production.

Sugar is caramelized when it is melted into a clear golden to dark brown syrup, reaching a temperature from 320 to 356 degrees F. It goes through many stages which are determined by the recipe being made.

At 338 degrees F, the sugar syrup begins to caramelize creating an intense flavor and rich color, from light and clear to dark brown. Depending upon when the cooking stops and it cools and hardens, caramel textures can range from soft to brittle. A soft caramel is a candy made with caramelized sugar, butter and milk. Crushed caramel is used as a topping for ice cream and other desserts.

The large brown molecules (caramelin, caramelen and caramelan) are what give caramel its color, its viscosity and its stickiness. The aroma molecules give caramel its flavor.

Caramel colors, i.e. ammonia caramel, ammonia sulphite caramel, and caustic caramel are the most widely used food additives and are found as coloring agents in a wide range of foods and beverages.
Process of caramelization 

Crystallization process of sugar

Crystallization is a process of formation of solid crystals precipitating from a solution through a natural or an artificial method. Crystallization is a separation process, widely applied in the chemical and pharmaceutical industry. The principle of crystallization is based on the limited solubility of a compound in a solvent at a certain temperature, pressure, etc. A change of these conditions to a state where the solubility is lower will lead to the formation of a crystalline solid.

All crystallization processes are aimed at creating a supersaturated solution or melt. The super-saturation is the driving force under whose influence new crystals are formed and present crystals grow.

Crystallization remains the preferred means of separating sugar from the impurities. As the sugar crystal is extremely selective as to what it builds into its lattice, theoretically absolutely pure crystals can be produced by crystallization.

Sugar has a very high solubility in water (solutions range from 10 to 30% water content) so solutions are very viscous. This is a significant constraint in processing. Having prepared sugar crystals, it is necessary to separate them from the mother liquor (molasses). This is carried out in high speed centrifuges.

In making icings, frostings, or candy like fondant and fudge, it is necessary to crystallize the sugar solution. For crystallization to occur, nuclei must form in the solution. To these nuclei the material of the solution is added to form crystals. Both the rate of formation of nuclei and the rate of crystallization are affected by the nature of the crystallizing substance, the concentration, the temperature, agitation, and the impurities present in the solution.
Crystallization process of sugar

Production of fondant

Fondant is a mixture of very fine sugar crystals of size below 44 μm, surrounded by a saturated solution of sweetener components. It is an edible icing used to decorate or sculpt cakes and pastries.

Sugar and glucose syrup, usually in the ratio of 3 to 4 to 1, are dissolved in water at 110-112 °C. This solution has a concentration of about 80 % solids and is then further concentrated to 88% by boiling to 117-119 °C.

The syrup is cooled to 38-40 °C, it is now a supersaturated solution an in this condition, is delivered to a beater-cooler.

Cooling is accomplished either by a large rotating drum that is internally water-cooled or by a water-jacket tube with an internal screw. The cooled syrup is transferred into a beating chamber where a revolving blade shaft produces the agitation necessary to rapidly crystallize the fondant syrup.

The finished products contain 5% invert sugar on a dry basis. Inverts sugar functions as a humectants that is essential in cream centers and icings.

To prepare small fondant pieces for subsequent coating, the fondant must be remelted so that it can be cast into molds or chocolate shells.

Fondant has been used in the food, baking, and confectionary industries for a long time. In the beginning, the confection industry used it for candy cream centers.
Production of fondant

Sugar crystallization

Crystallized sugar looks like damp, white sand. It happened often as a result of not being properly melted during cooking. If even one sugar crystal comes into contact with cooked syrup, it can start a chain reaction that turns the whole thing into a mass of sugar crystals.

Crystallization can occur when granulated particles of sugar come in contact with melted particles, or when the melted sugar is agitated too much during cooking.

This can be controlled by a process called inversion. Inversion is a chemical change to regular sugar into another form of sugar that resists crystallizing.

If an acid, such as cream of tartar or lemon juice, is added to a syrup before or during cooking, some of the sugar is inverted. Glucose or corn syrup may also be added to control crystallization in boiling syrup. 

Crystallization also may be prevented by brushing down the sides of the pan with water during the cooking process.

Sugar is purposely crystallized during the cooking process for crystalline confections like fondants and fudge because controlled crystallization forms thousands of microscopic sugar crystals that create smooth and creamy texture.

Conversely, crystallization must be avoided during the production of non-crystalline confections such as caramels, hard candies and toffees.
Sugar crystallization

Caramelization

Sugars, polysaccharides, polyhydroxycarboxylic acids, reductones, alpha-dicarbonyl compounds and quinines will undergo browning in the absence of amino acids.

When concentrated solution of sugars is heated to temperatures above 100 ° C, various thermal decomposition reactions can occur leading to formation of flavor compound and brown-colored products. When sucrose is heated to about 135 °C it melts and turns brown.

This process is called caramelization. Many carbohydrates undergo this process. Caramelization is accelerated by carboxylic acids and their salt, phosphate and metallic ion, but even when catalyzed, the energy requirements exceed those of a sugar-amine reactions.

If heating is continued the sugar becomes darker still, and eventually very pure carbon is obtained.

During caramelization, the first reaction step is the reversible isomerization of aldoses or ketoses in their open chain forms to form an enediol intermediate. Caramel has an attractive bitter sweet taste and a typical aroma.

This forms the basis of a whole industry dedicated to the production of caramel colors for food use, e.g. in cola beverages, beers, gravy browning.
Caramelization