What is Polysorbate 60 (E435) in Food? Uses, Safety, Tips

Polysorbate 60, also known as Polyoxyethylene (20) Sorbitan Monostearate and designated as E435 in the European food additive numbering system, is a widely used emulsifier in the food industry. This synthetic compound helps to create and stabilize mixtures of oil and water, contributing to the texture, appearance, and shelf life of a variety of food products. This article provides an in-depth look at Polysorbate 60, exploring its chemical nature, how it’s made, its functions in food, its applications, safety considerations, and tips for using it.

What is Polysorbate 60 (E435) in Food?

Polysorbate 60 is a non-ionic emulsifier and surfactant belonging to the family of Polysorbates, which are derived from sorbitan (a derivative of sorbitol) esterified with fatty acids and approximately 20 moles of ethylene oxide. Specifically, Polysorbate 60 is synthesized by reacting sorbitol with stearic acid (a saturated fatty acid typically derived from vegetable oils like palm oil) and then with ethylene oxide. The “60” in its name refers to the fatty acid component, in this case, monostearate, while the “polyoxyethylene (20)” indicates that there are 20 repeating units of ethylene oxide in the molecule.

The resulting compound is a complex mixture of related compounds, all sharing a similar structure with a hydrophilic (water-loving) head and a hydrophobic (oil-loving) tail. This amphiphilic nature is what makes Polysorbate 60 an effective emulsifier, allowing it to interact with both oil and water phases. Unlike natural emulsifiers like egg yolk, which contain a mixture of different emulsifying agents, Polysorbate 60 is a synthetically produced compound designed for specific functional properties. It is more comparable to other synthetic emulsifiers like Sodium Stearoyl Lactylate (E481) or Polyglycerol Esters of Fatty Acids (E475) in terms of its targeted functionality. It is often used in conjunction with other types of emulsifiers to achieve optimal results.

How is Polysorbate 60 (E435) Made?

The production of Polysorbate 60 involves a multi-step chemical synthesis process:

1. Sorbitol Dehydration and Cyclization: The process begins with sorbitol, a sugar alcohol typically derived from corn starch. Sorbitol is dehydrated and cyclized to form sorbitan, a cyclic molecule.
2. Esterification with Stearic Acid: The sorbitan is then esterified with stearic acid, a saturated fatty acid. Stearic acid is usually derived from vegetable oils, such as palm oil or coconut oil. This reaction attaches the hydrophobic “tail” to the sorbitan molecule, forming sorbitan monostearate.
3. Ethoxylation: The final step is the ethoxylation of sorbitan monostearate. This involves reacting the sorbitan monostearate with ethylene oxide, a highly reactive chemical compound. Approximately 20 moles of ethylene oxide are added per mole of sorbitan monostearate. The ethylene oxide units form polyoxyethylene chains, which constitute the hydrophilic “head” of the molecule. This addition of the hydrophilic head gives Polysorbate 60 its amphiphilic nature and its ability to function as an emulsifier.

The resulting Polysorbate 60 is a viscous, yellow to amber-colored liquid at room temperature. It is soluble in water, ethanol, and other polar solvents. The specific properties of Polysorbate 60, such as its HLB (Hydrophilic-Lipophilic Balance) value, are determined by the degree of ethoxylation and the type of fatty acid used in the esterification step. The manufacturing process is carefully controlled to ensure the desired chemical structure and purity of the final product. It is different from the production process of natural emulsifiers like beeswax or from other synthetic emulsifiers like sucrose esters.

How Does Polysorbate 60 (E435) Work in Food?

Polysorbate 60 functions primarily as an emulsifier in food, stabilizing oil-in-water emulsions. Its amphiphilic nature, with both hydrophilic and hydrophobic components, is the key to its functionality. The effectiveness of emulsifiers like Polysorbate 60 can be attributed to their ability to perform the following actions:

1. Reducing Interfacial Tension: When added to a mixture of oil and water, Polysorbate 60 molecules migrate to the interface between the two phases. The hydrophobic fatty acid tail embeds itself in the oil phase, while the hydrophilic polyoxyethylene head extends into the water phase. This orientation significantly reduces the interfacial tension between the oil and water, making it easier for the two phases to mix and form an emulsion.
2. Forming a Protective Film: The Polysorbate 60 molecules form a protective film or barrier around the dispersed oil droplets. This film prevents the oil droplets from coming into direct contact and coalescing, which would lead to the separation of the emulsion. The polyoxyethylene chains extending into the water phase also create a steric hindrance effect, further preventing droplet aggregation.
3. Promoting Droplet Dispersion: During the mixing or homogenization process, Polysorbate 60 helps to break down the oil phase into smaller droplets and facilitates their dispersion throughout the water phase. The smaller the droplet size, the greater the surface area, and the more stable the emulsion tends to be.
4. Solubilization: In addition to emulsification, Polysorbate 60 can also help to solubilize or disperse oil-soluble ingredients, such as flavors, colors, or vitamins, in water-based food systems. It can form micelles, tiny spherical structures that encapsulate the oil-soluble substances within their hydrophobic core, allowing them to be dispersed in the aqueous phase.

Compared to other emulsifiers, like PGPR or Sorbitan Tristearate, Polysorbate 60 is more hydrophilic, with an HLB value around 14.9, making it more suitable for stabilizing oil-in-water emulsions. It is often used in combination with other types of emulsifiers to achieve optimal emulsion stability and texture.

Uses of Polysorbate 60 (E435) in Food

Polysorbate 60’s ability to create and stabilize oil-in-water emulsions, along with its other functionalities, makes it a valuable ingredient in a wide range of food products:

• Baked Goods: In cakes, muffins, bread, and other baked goods, Polysorbate 60 improves dough handling, increases loaf volume, and creates a finer, softer crumb structure. It also helps to retain moisture, extending the shelf life of the baked goods. It can be used alongside other emulsifiers like Sodium Stearoyl Lactylate (E481) to achieve synergistic effects.
• Frozen Desserts: In ice cream, sherbet, and other frozen desserts, Polysorbate 60 helps to create a smooth and creamy texture by controlling ice crystal formation during freezing. It also stabilizes the air bubbles incorporated during the whipping process, contributing to the desired overrun and lightness of the product. It may be used in conjunction with stabilizers like guar gum or carrageenan.
• Whipped Toppings: Polysorbate 60 is often used in whipped toppings, both dairy and non-dairy, to improve their whipping properties and stabilize the foam structure. It helps to incorporate and retain air bubbles, creating a light and airy texture that holds its shape.
• Creamy Dressings and Sauces: In creamy salad dressings, sauces, and dips, Polysorbate 60 helps to create and maintain a stable emulsion, preventing the oil and water phases from separating. It also contributes to a smooth and consistent texture. It’s often used in combination with other emulsifiers like lecithin or mono- and diglycerides.
• Confectionery: In some confectionery products, Polysorbate 60 can be used to modify fat crystallization, improve gloss, and prevent fat bloom. It can also help to create stable emulsions in fillings and coatings.
• Beverages: Polysorbate 60 can be used to solubilize and disperse oil-based flavors, colors, and vitamins in beverages, ensuring a uniform appearance and taste. It can also help to create and stabilize cloud emulsions in certain drinks. It’s less commonly used for this purpose compared to sucrose esters.
• Processed Foods: In a variety of other processed foods, such as soups, gravies, and ready-to-eat meals, Polysorbate 60 can improve texture, stability, and overall quality. It can also be used in low-fat or reduced-fat products to help mimic the mouthfeel and texture of full-fat versions.

Is Polysorbate 60 (E435) Safe to Eat?

Polysorbate 60 has undergone extensive safety testing and is generally recognized as safe (GRAS) by the U.S. Food and Drug Administration (FDA) and is approved as a food additive in the European Union (E435) and many other countries. Regulatory agencies have established an Acceptable Daily Intake (ADI) for Polysorbate 60.

Acceptable Daily Intake (ADI): The ADI for polysorbates (including Polysorbate 60, Polysorbate 20, and Polysorbate 80) is typically set at 25 mg/kg body weight per day. This represents the amount that can be safely consumed on a daily basis over a lifetime without any appreciable health risk. The actual intake of Polysorbate 60 from food is generally much lower than the ADI.

Potential Side Effects:

• Gastrointestinal Effects: Some studies have suggested that consuming very high doses of polysorbates may cause mild gastrointestinal discomfort, such as diarrhea or abdominal cramping, in some individuals. However, these effects are typically associated with doses far exceeding those found in food products.
• Allergic Reactions: Although rare, allergic reactions to polysorbates have been reported. Symptoms may include skin rashes, itching, or swelling. Individuals with known sensitivities to polysorbates should avoid products containing them.
• Ethylene Oxide and 1,4-Dioxane: There are concerns about potential residues of ethylene oxide (used in the ethoxylation process) and its byproduct, 1,4-dioxane, in Polysorbate 60. Both substances are considered potentially carcinogenic at high levels. However, regulatory agencies have established strict limits for these residues in food additives, and manufacturers employ purification steps to minimize their presence in the final product. The levels found in Polysorbate 60 are generally considered safe.

While generally considered safe, there is ongoing research into the potential effects of polysorbates, including Polysorbate 60, on the gut microbiome and their potential link to inflammation and metabolic disorders. Some studies have suggested that certain emulsifiers may disrupt the gut microbiota and contribute to low-grade inflammation. However, more research is needed to fully understand these potential effects and their relevance to human health at typical consumption levels.

Tips for Using Polysorbate 60 (E435) in Food

When using Polysorbate 60 in food formulations, it’s important to keep these tips in mind:

1. Proper Dispersion: Polysorbate 60 should be properly dispersed in the aqueous phase before combining with the oil phase. This ensures that it can effectively position itself at the oil-water interface and perform its emulsifying function. Thorough mixing or homogenization is often necessary to achieve a stable emulsion.
2. Dosage: The appropriate dosage of Polysorbate 60 depends on the specific application and the desired texture and stability. Typical usage levels range from 0.1% to 0.5% of the total weight of the product. It’s generally recommended to start with a low dosage and gradually increase it until the desired effect is achieved. Using it at the right level is crucial for the effectiveness of emulsifiers.
3. Temperature: Polysorbate 60 is generally heat-stable and can withstand typical food processing temperatures. However, excessive heating should be avoided, as it may degrade the emulsifier and affect its functionality.
4. Synergistic Effects: Polysorbate 60 can be used in combination with other emulsifiers or stabilizers to achieve synergistic effects. For example, it’s often used with mono- and diglycerides or sodium stearoyl lactylate in baked goods, or with guar gum or carrageenan in frozen desserts.
5. Regulatory Compliance: Always ensure that the use of Polysorbate 60 complies with relevant food regulations and labeling requirements in your country or region. Different countries may have specific restrictions or limitations on its use.

Conclusion

Polysorbate 60 (E435) is a widely used and highly effective emulsifier that plays a crucial role in the food industry. Its ability to stabilize oil-in-water emulsions, improve texture, and extend the shelf life of various food products makes it a valuable tool for food manufacturers. While generally recognized as safe, ongoing research continues to explore its potential effects on human health, particularly in relation to the gut microbiome. As our understanding of this synthetic emulsifier deepens, we can expect further refinements in its use and the development of new and innovative applications in the ever-evolving landscape of food technology. The use of both natural emulsifiers and synthetic emulsifiers like Polysorbate 60 will continue to shape the future of food production, providing solutions for creating stable, appealing, and convenient food products.

Sources

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