Factors That Affect Sugar Crystallization

Sugar Crystallization is the process of solid crystals precipitating from a solution, either naturally or artificially. It’s also a chemical solid-liquid separation process that involves the mass transfer of a solute from a liquid solution to a crystalline phase in the form of a solid. As a result, crystallization is a precipitation process resulting from a change in the solubility of the solute in the solvent. Nuclei creation and crystal development are the two key processes in the crystallization process. Alaqua is a processing equipment supplier for the evaporator, crystallizer, distillation equipment, spray dryer, heat exchanger, and solvent recovery systems.

Factors Affecting Sugar Crystallization:

Manufacturers need to crystallize the sugar solution to produce icings, frostings, or sweets like fondant and fudge. Nuclei must develop in the fluid before crystallization can begin. Adding solution material to these nuclei forms crystals.The type of crystallizing material, the concentration, temperature, agitation, and contaminants present in the solution all influence the rate of nuclei production and crystallization.

Nature of crystallizing substance:

Some substances, such as salt, crystallize rapidly from a solution of water. Nuclear formation begins with only a small super-saturation, and any additional salt in the solution beyond the saturation threshold crystallizes. Some chemicals, such as salt, do not readily form nuclei or crystallize. Crystallization often requires a high level of supersaturation for sucrose to initiate. Compared to levulose, sucrose crystallizes faster.

Nuclei formation-

To initiate crystallization, nuclei need a supersaturated solution. Several variables impact the nuclei-creation process, which involves the joining of atoms to create nuclei. If a solution is allowed to stand, it may spontaneously develop a few nuclei in various areas, and crystallization will proceed from these nuclei.The crystals grow to a considerable size when just a few nuclei form spontaneously in the solution. In most cases, nucleus production and crystallization do not commence right after supersaturation. Specks of dust in the solution may help accelerate nuclear production. The pace of nuclear production is sped up by agitating or churning a solution. A decline in temperature encourages the creation of nuclei initially but eventually slows it down. Utilize seeding to initiate crystallization instead of relying on spontaneous nuclei development.

Seeding-

Seeding is the technique of adding crystals of the same substance to start crystallization. These crystals act as nuclei for the formation of new crystals. If the supplier provides a substantial number of crystals with modest sizes, the solution harbors numerous nuclei, yielding tiny crystals. When the supplied material is minimal, the process generates few nuclei, resulting in the formation of massive crystals. Despite the common belief that all crystals are large enough to be seen, in reality, many are incredibly tiny—so small that they can float in the air. If crystals are floating in the air, they may act as seed solutions, causing crystallization to begin.

Rate of crystallization:

The solution deposits new molecules onto the nuclei generated in a regular sequence or manner, thereby giving each crystal a characteristic shape. A crystal’s growth rate might differ depending on which side or face it is on. The rate of crystallization refers to how quickly nuclei expand in size. The concentration and temperature of the solution may promote this pace; foreign elements may slow it down.

Solution Concentration-

A concentrated solution assists in forming nuclei. 114°C fondant syrup cooked to 111°C has less water and is more concentrated. As a result, the one cooked to 114°C forms nuclei more easily. If the degree of supersaturation is moderate, the formation of large, well-shaped crystals occurs more easily. Supersaturation between 70°C and 90°C represents the most favorable condition for crystal formation in a sucrose solution cooked to 112°C. Agitating the syrup at these temperatures induces relatively rapid crystallization, resulting in larger crystals compared to cooling the syrup to a lower temperature.The growth of tiny crystals necessitates supersaturation and a low temperature.

sugar Crystallization Temperature–

Chemical precipitates tend to develop larger crystals when crystallized at high temperatures. This principle applies broadly to sugars. All else being equal, higher temperatures lead to the formation of coarser crystals.

Agitation-

Stirring a solution promotes nuclei production while preventing the deposit of solution material on already formed nuclei. As a result, crystals in agitated solutions do not grow to the same size as crystals that form naturally. To find tiny crystals, create conditions that facilitate the generation of a large number of nuclei. Stir the syrup until it reaches a kneadable consistency to produce small crystals in syrups with known concentration and temperature. Churning the syrup briefly generates some nuclei, but stopping the agitation discourages the formation of additional nuclei and promotes crystal growth.If tiny crystals are needed, it is critical to mix candy and frosting syrups until almost all of the material has crystallized.

Large sugar crystals can develop when impurities in the sugar syrup are present. Impurities encourage the production of premature crystals, which can grow to be large and bothersome.

Interfering substances-

Certain goods can be introduced to inhibit crystal formation and development. Interfering agents are things like cream, butter, and egg white. The agents cover the crystals and prevent huge crystals from forming. Boiling the sugar syrup to the correct temperature is very critical, as is ensuring that the sugar is completely dissolved.

Degree of inversion-

Sweets with a high sugar content (sucrose) may crystallize during production or storage (commonly referred to as graining). Although this is beneficial in some items (such as fondant and fudge), it is seen as a quality flaw in most others.

When a sugar solution is heated, a portion of the sucrose is converted to inverted sugar. This inverted sugar prevents sucrose crystallization while also increasing the total sugar content in the mixture. The natural inversion process makes it impossible to predict the amount of inverted sugar that will be created. To limit the inversion, one can use certain substances, such as cream of tartar or citric acid.These additives speed up the conversion of sucrose to invert sugar, increasing the total proportion of inverted sugar in the solution. Adding glucose syrup, which will immediately increase the quantity of inverted sugar in the mixture, is a more precise way of assuring the right balance of inverted sugar.

Keep the inverted sugar in the sweet under control, as an excessive amount will cause it to absorb water from the air and become sticky. If there isn’t enough inverted sugar, the sucrose will crystallize. A non-crystalline product requires about 10-15% inverted sugar.

Added ingredients:

Adding specific components can influence the boiling temperature. For instance, when making toffees using liquid milk, the mixture’s moisture level instantly increases, requiring a longer boiling time to achieve the necessary moisture content.

The shelf-life of the sweet is also affected by the additional additives. The viscosity of toffees, caramels, and fudges, which include milk solids and fat, is greater, which prevents sugar Crystallization. Fats, on the other hand, may cause the sweet to get rancid, reducing its shelf life.

Alaqua is a processing equipment including crystallizers supplier in USA that also offers installation and commissioning, equipment fabrication, troubleshooting, personnel training, and various other services. Contact us today for processing equipment and their services!

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