Effects of Sodium carboxymethyl cellulose on the Production of Ice Cream
Why is Sodium carboxymethyl cellulose of Low Degree of Substitution Chosen in Ice Cream
Sodium carboxymethyl cellulose is used as a thickener in ice cream mainly to provide the viscosity for the mixed solution, thus preventing the fat in the material and liquid from floating. In the actual production, Sodium carboxymethyl cellulose mainly has a greater impact on the process homogenization. After the material and liquid are mixed, due to the presence of fat, protein, milk mineral, etc., if not immediately homogenized, then layering will occur. According to Stokes’ law, in order to prevent the mixed solution from layering, the viscosity of material and liquid should be increased, which can be achieved by adding the Sodium carboxymethyl cellulose of a certain viscosity. Since the mixed solution system of ice cream is relatively complex and contains a variety of ingredients, it is more difficult to stabilize the system by one kind of thickening agent, and in the actual production, the compound of Sodium carboxymethyl cellulose and other thickeners is generally used.
Furthermore, after Sodium carboxymethyl cellulose and other thickeners are added into the mixed solution, the particles such as protein and fat can be effectively absorbed on the surface layer, thereby improving the uniformity of the whole mixed solution system and helping to improving the efficiency of homogenization. For example, guar gum has good water solubility, strong water absorption, high viscosity, short aging time, and good synergistic interaction with other colloids; carrageenan has stronger gel property and higher viscosity, the ability to stabilize the casein micelles and to improve the stability of ice cream paste, as well as good solubility in the mouth and whipping properties; Sodium carboxymethyl cellulose can make the organization of product smooth, the tongue sense good, chewable, and the texture of product smooth; monoglyceride makes the surface tension of mixture increased, and the bubble diameter reduced by nearly half. Therefore, the appropriate combination of the above emulsion stabilizers can not only give full play to their respective advantages and create synergy, but also improve the taste, texture, structure and flavor of product.
Effects of Sodium carboxymethyl cellulose on the Production of Ice Cream
3.1.2 Effects of Sodium carboxymethyl cellulose on the Quality of Ice Cream
Freeze blending is the last key process in the formation of ice cream. In this process, the ice cream is changed from the rich mixed solution into the solid with a delicate taste and swelling volume. The effects of Sodium carboxymethyl cellulose on the quality of ice cream mainly lie in the effects on the freeze blending of mixed solution.
3.1.2.1 Effects of Sodium carboxymethyl cellulose on the Organizational Structure of Ice Cream
Whether the structure of ice cream is fine and delicate is related to the size and shape of ice crystals. Since the mixed solution to form ice cream contains about 65% of moisture, when the temperature reaches the freezing point of water, crystallization will occur. The size and shape of ice crystals are related to the model, the addition amount, and the freeze blending speed of Sodium carboxymethyl cellulose. Generally speaking, the smaller the crystals are and the more regular the shape is, the more smooth the ice cream will be and the more delicate the taste will be. In general, Sodium carboxymethyl cellulose with higher degree of substitution (DS≥0.92) has stronger water retention. If Sodium carboxymethyl cellulose with higher degree of substitution is used in ice cream, since it can easily absorb more free water in the mixture, it will affect the uniform distribution of water in the mixed solution, make the crystals in the formed ice cream of various sizes, and also affect the taste of ice cream. So we think that in ice cream Sodium carboxymethyl cellulose with not too high degree of substitution (DS = 0.70-0.85) should be used.
3.3.2.2 Effects of Sodium carboxymethyl cellulose on the Expansion Rate of Ice Cream
The expansion of ice cream is mainly because the ambient air is continuously mixed into the mixture during freeze blending, making its volume increased to a certain degree. The expansion rate is related to the temperature, the viscosity, and the freeze stirring speed of mixture. Adding Sodium carboxymethyl cellulose can increase the viscosity of mixed solution and help to improve the expansion rate, but if the viscosity of mixture is too high, then too much air will be mixed during freeze blending and the ice cream obtained will be too loose. Therefore, Sodium carboxymethyl cellulose used in ice cream should also be not very high in the viscosity.
3.1.2.3 Effects of Sodium carboxymethyl cellulose on the Melting Rate of Ice Cream
The melting rate of ice cream is related to the number of bubbles, the type and the addition amount of thickener in the product. When the high viscosity Sodium carboxymethyl cellulose is used, it enables the ice cream to produce more bubbles during freeze blending. The more bubbles there are in the product, the more uniform it will be and it can effectively prevent the heat transfer, thereby reducing the melting rate. Therefore, generally the more frequently used in the ice cream is Sodium carboxymethyl cellulose of FVH6 type.
3.1.3 Advantages of Sodium carboxymethyl cellulose in the Processing of Ice Cream
3.1.3.1
The viscosity of Sodium carboxymethyl cellulose is reversible at different temperatures. When the sugar melting of ice cream comes, Sodium carboxymethyl cellulose is just at the high temperature and Sodium carboxymethyl cellulose at this time has smaller viscosity; in contrast, during cooling and aging stages, the viscosity will increase with the drop in the temperature, which greatly helps to improve the expansion rate of ice cream and prevent the generation of ice particles in ice cream, that is, can withstand sudden changes in temperature. But when people eat, the viscosity will decrease with increasing temperatures. In this way, it can play a role in resistance to melting, leavening (an increase of 1/3 than the original volume), whitening in color, as well as smooth and delicate taste. In addition, Sodium carboxymethyl cellulose is small in the addition amount (using only about five thousandths), easy to use, easy to control the quality, short in the aging time, so suitable for the mass production of modernized beverage industry. The average addition amount is 0.5%.
Sodium carboxymethyl cellulose will decrease in the viscosity in the presence of shear force, and the value of viscosity will be smaller with the increase of shear force. This property helps to reduce energy consumption and improve the homogenizing efficiency during homogenizing, blending and pipeline transportation; on the other hand, it makes the product feel delicate, refreshing, and beneficial to the release of flavor because the chewing of tongue generates the shear force when ice cream enters into the mouth.