The prominent role of thickeners in food

　　Food additive manufacturers explain that food thickeners are one of the important auxiliary ingredients in the food industry. In food processing, they primarily serve to stabilize the physical form of foods—for example, maintaining the stability of suspended slurries, ensuring consistent smoothness, and stabilizing emulsion systems. Moreover, they can enhance the texture of foods and improve the stability of color, aroma, flavor, and the consistency of liquid formulations in processed foods. The key roles of thickeners in food are mainly manifested as follows:
　　(1) Thickening, dispersing, and stabilizing effects: Food thickeners are all hydrophilic polymeric substances. When dissolved in water, they exhibit high viscosity, imparting a thickened texture to the system. Once the viscosity increases, the dispersed phase within the system becomes less likely to aggregate or coalesce, thereby ensuring the stability of the dispersion. Most thickeners also possess surfactant properties, enabling them to adsorb onto the surface of the dispersed phase, endowing it with a certain degree of hydrophilicity and facilitating its dispersion in aqueous systems. The molecular weight distribution, concentration, solution temperature, pH value, and shear rate of the thickener all influence the viscosity of the solution.
　　(2) Gelation: Certain thickeners, such as gelatin and agar, exist as viscous fluids under warm conditions. However, when the temperature drops, the molecules in the solution link together to form a network structure, trapping the solvent and other dispersed media within this network. As a result, the entire system transforms into a semi-solid with no fluidity—what we call a gel. Many food-processing applications take advantage of this property of thickeners, such as making jellies and milk puddings. Some ionically charged water-soluble polymeric thickeners, like sodium alginate, can form gels even in the presence of high-valence ions, independent of temperature. This characteristic greatly facilitates and enhances the processing of many specialty foods. It is worth noting, however, that not all food thickeners are capable of forming gels, and their gel-forming properties cannot be interchanged when applied to food systems. The reason lies in the fact that different thickeners vary significantly in terms of their gelation mechanisms, gel quality, stability, and acceptability in terms of texture and mouthfeel.
　　(3) Coagulation and Clarification Effect: Most thickeners are polymeric materials. Under certain conditions, they can simultaneously adsorb multiple dispersed media, causing them to aggregate and separate, thereby achieving purification or clarification. For example, adding a small amount of gelatin to fruit juice can produce clear, unclouded juice.
　　(4) Water-retention effect: Hydrophilic thickeners are all hydrophilic polymers with strong water-absorbing properties. When added to food products, they help maintain a certain level of moisture content, thereby ensuring a good texture and mouthfeel. The hydrophilic nature of thickeners plays an important role in improving the quality of meat and noodle products. For instance, in noodle-based foods, thickeners can enhance the dough’s water absorption capacity. During dough preparation, thickeners accelerate the rate at which water penetrates protein molecules and starch granules, facilitating the dough-mixing process. Thickeners can absorb dozens or even hundreds of times their own weight in water while retaining that water—this property helps improve the dough’s water-holding capacity and increase the product’s weight. Moreover, due to their gel-forming characteristics, thickeners enhance the viscoelasticity of noodle products, promote greater α-starch conversion, and reduce the likelihood of staling and drying out.
　　(5) Controlling Crystallization: The use of thickeners can impart higher viscosity to foods, thereby preventing crystal precipitation in many supersaturated solutions or systems, or achieving a fine-crystal texture. For example, when used in confectionery and frozen foods, thickeners can enhance the product’s expansion, reduce the likelihood of ice crystal formation, and result in a smoother mouthfeel. They can also control sugar syrup products from crystallizing again, minimize the formation of ice crystals in ice cream products, or refine ice crystals generated during processing—and incorporate numerous tiny air bubbles—thus creating a fine, uniform texture, a smooth mouthfeel, and an aesthetically pleasing appearance.
　　(6) Film-forming and保鲜 effects: Edible thickeners can form a very smooth, protective film on the surface of food, shielding it from the effects of oxygen and microorganisms. When used in combination with food surfactants, they can help preserve fruits and vegetables while also imparting a polishing effect. Additionally, these thickeners can prevent moisture absorption on the surfaces of frozen foods and solid powdered foods, thereby avoiding quality deterioration. Food thickeners used for film formation include alcohol-soluble proteins, gelatin, agar, and alginates.
　　(7) Foaming and Foam-Stabilizing Effects: Thickening agents can generate foam and form a network structure. When stirred, their solutions behave like soap bubbles, capable of trapping large amounts of gas and liquid bubbles, thereby increasing the surface viscosity of processed foods and enhancing their stability. When thickening agents such as carrageenan, locust bean gum, sodium alginate, and gelatin are used as foaming agents in cakes, bread, ice cream, and other products, they can significantly boost both the volume and stability of the foam. For example, the foam in beer and the “beard” that forms on the bottle walls are both attributable to the use of thickening agents.
　　(8) Adhesive作用: The purpose of using locust bean gum and carrageenan in sausages is to create a cohesive product with a stable, smooth texture after homogenization. Additionally, the water-retention properties of these gums help prevent weight loss during storage. Gum arabic can serve as a binding agent for tablet and granular products and is used in the granulation of powdered foods, the granulation of food flavorings, and other applications.
　　(9) Use in the production of health-care and low-calorie foods: Many thickeners are essentially natural macromolecular substances belonging to the gel-forming class. They are hardly digested by the human body and are excreted through metabolic processes. Therefore, when thickeners replace part of the syrup and protein in food products, it becomes relatively easy to reduce the food’s caloric value. This approach has already been applied to processed foods such as jams, fruit purees, condiments, desserts, cookies, and puddings, and continues to expand into broader applications. In 1961, researchers discovered that pectin could lower blood cholesterol levels, and sodium alginate also exhibits this effect. The therapeutic benefits of natural gels have made them important ingredients in health-care foods.
　　(10) Masking and Sustained-Release Effects: Some thickeners have adsorption and masking effects on the undesirable odors inherent in certain raw materials, thereby achieving deodorization and removal of fishy smells—for example, the use of cyclodextrins for odor control. Additionally, these thickeners can exert a sustained-release effect on certain volatile aromas and unstable nutritional components.