The Role of Emulsifiers in Biscuits: Functional Analysis and Application Guide

Biscuits, as widely popular baked goods, owe their quality characteristics (such as crispness, texture, appearance, and shelf life) largely to the scientific application of emulsifiers in formulations. Although typically added at only 0.1%-0.5% of flour weight, emulsifiers significantly improve dough processability, product textural properties, and storage stability. This paper systematically elaborates the core mechanisms of emulsifiers in biscuits, including oil emulsification, dough improvement, structure loosening, anti-staling preservation, and provides detailed functional analysis of commonly used emulsifiers such as monoglycerides, soy lecithin, sodium stearoyl lactylate (SSL), diacetyl tartaric acid ester of mono- and diglycerides (DATEM), sucrose esters, and sorbitan monostearate (SPAN), offering theoretical references for biscuit formulation optimization.

Biscuits are baked goods primarily made from wheat flour, sugar, and oils/fats, characterized by crispy or soft textures. During biscuit production, the dispersion state of fats, rheological properties of dough, expansion effect during baking, and final product texture and shelf life are all closely related to the application of emulsifiers. As surface-active substances, emulsifiers can form adsorption films at oil-water interfaces, reducing interfacial tension and thereby stabilizing emulsion systems . In biscuits, emulsifiers improve product quality through multiple mechanisms, making them indispensable functional ingredients in biscuit formulations.

1 Oil Emulsification and Uniform Dispersion

The most fundamental function of emulsifiers is to promote uniform dispersion of fats in dough. Fats used in biscuit production (such as shortening and margarine) need to be uniformly distributed in the dough to form a crispy texture. Emulsifiers reduce interfacial tension between oil and water, making fats finer and forming stable emulsion systems, effectively preventing oil exudation . This uniformly dispersed fat forms a continuous fat film during baking, giving biscuits their unique crispy texture.

2 Improving Dough Processability

Emulsifiers significantly improve the mechanical processability of dough. During dough mixing, emulsifiers interact with gluten proteins, regulating the gluten network structure to give the dough appropriate elasticity and extensibility . This is particularly important for mechanical forming and demolding. For example, sodium stearoyl lactylate (SSL) enables easy demolding of biscuits, neat appearance, and clear layers . Additionally, emulsifiers prevent dough from sticking to rollers, improving production efficiency .

3 Promoting Structure Loosening

During baking, emulsifiers promote the formation of loose structures in biscuits. Research shows that diacetyl tartaric acid ester of mono- and diglycerides (DATEM) expands when heated during baking, causing proteins to foam easily, increasing volume and gradually solidifying with baking, forming a porous sponge-like loose structure in the center layer . This loose structure directly affects biscuit crispness and mouthfeel.

4 Controlling Fat Crystallization

Emulsifiers can regulate the crystallization behavior of fats, affecting biscuit textural properties. Studies have found that the microstructure and physical properties of emulsifier-based oleogels are closely related to biscuit quality. Biscuits prepared with monoacylglycerol (MAG) and sorbitan monostearate (SPAN) showed similar hardness and color to shortening biscuits, with uniformly porous cross-sections . Higher shear viscosity (at 25°C) was identified as a key factor for producing softer cookies .

5 Antioxidant Effects and Shelf Life Extension

Certain emulsifiers exhibit antioxidant effects or can synergize with antioxidants. Research shows that in cookies stored at 40°C for 12 months, lecithin demonstrated strong antioxidant effects . Sorbitan monostearate also showed synergistic effects when combined with mixed tocopherol concentrates . Additionally, emulsifiers can interact with amylose, retarding starch retrogradation and preventing biscuit deterioration .

6 Reducing Fat Content

The application of emulsifiers can achieve fat reduction while maintaining product quality. Studies indicate that adding 0.125-0.5% DATEM can reduce fat content in biscuits by about 20%, achieving good health benefits without compromising eating quality . In reduced-fat biscuit development, SSL has also shown effectiveness in improving sensory characteristics .

 Performance Comparison of Common Biscuit Emulsifiers

 1 Glycerol Monostearate

Glyceryl monostearate is one of the most commonly used emulsifiers in biscuit production, with an HLB value of approximately 3.8, exhibiting strong lipophilic properties. Its main effects in biscuit production are:

Fat Emulsification and Leakage Prevention:** Monoglycerides emulsify and evenly disperse fats in the dough, effectively preventing fat leakage during baking and thus improving the crispness of the biscuits. This is crucial for maintaining a crisp texture and preventing greasiness.

Dough Improvement: Monoglycerides interact with gluten proteins, regulating the gluten network structure and improving the dough's machinability, making it easier to shape and cut.

Compatibility with Other Emulsifiers:  Monoglycerides are often used in combination with other emulsifiers to achieve synergistic effects.

 2 Soy Lecithin

Soy lecithin is a natural emulsifier extracted from soybeans, characterized by high safety and alignment with clean label trends. Its applications in biscuits are unique:

Preventing Roller Sticking: Adding lecithin in biscuit production facilitates uniform fat mixing and effectively prevents dough from sticking to rollers, significantly improving biscuit quality .

Antioxidant Effects: Research shows that lecithin exhibits strong antioxidant effects in biscuits, effectively inhibiting oil oxidation and extending product shelf life .

Texture Improvement: Lecithin addition imparts finer texture and better melt-in-mouth sensation to biscuits. Due to its natural source, it is particularly suitable for clean-label product development.

3 Sodium Stearoyl Lactylate (SSL)

Sodium stearoyl lactylate is an anionic emulsifier with an HLB value of 8.3, capable of dual interaction with starch and protein. Its application effects in biscuits are significant:

Demolding and Appearance: SSL enables easy demolding of biscuits, neat appearance, and clear layers . This is particularly important for mechanical forming and high-efficiency production.

Crispy Texture: Biscuits with SSL exhibit crispy texture, attributed to its dual action of improving oil dispersion and regulating gluten network .

Anti-staling Preservation: SSL interacts with amylose to form insoluble complexes, retarding starch retrogradation and extending biscuit shelf life .

Fat Reduction Applications: In reduced-fat biscuit development, SSL improves sensory characteristics of biscuits formulated with fat replacers such as banana puree . Optimized formulations show that biscuits with 64.5% fat replacement by banana puree and 0.5g SSL exhibit physical properties comparable to control biscuits .

4 DATEM

DATEM is a non-ionic emulsifier with an HLB value of 8-9.2, primarily functioning as a dough strengthener. Its characteristics in biscuits include:

Improved Mechanical Processing: DATEM enables easier absorption of oils by gluten, improving dough mechanical processing properties .

Formation of Loose Structure: DATEM expands when heated during baking, causing proteins to foam easily, increasing volume and gradually solidifying during baking, forming a porous sponge-like loose structure in the center layer . This is precisely the source of biscuit crispness.

Fat Reduction: Adding 0.125-0.5% DATEM can reduce fat content in biscuits by about 20%, achieving good health benefits without compromising eating quality .

Shelf Life Extension: DATEM improves product looseness and mouthfeel while extending shelf life .

5 Sucrose Fatty Acid Esters

Sucrose fatty acid esters are emulsifiers made from sucrose and plant-derived fatty acids, offering a wide range of HLB values for selection according to specific needs . Their applications in biscuits include:

Starch Gelatinization Control: Sucrose esters control starch gelatinization and retrogradation behavior, improving biscuit texture stability .

Anti-stick Performance: Sucrose esters exhibit excellent anti-stick and anti-clumping properties, helping maintain biscuit appearance integrity .

High Efficiency at Low Usage: Sucrose esters demonstrate significant effects at very low addition levels (0.03%-0.5%), with minimal nutritional impact on finished products .

Heat Stability: Sucrose esters possess good thermal stability, suitable for high-temperature baking processes in biscuit production .

6 Sorbitan Monostearate (SPAN 60)

Sorbitan monostearate is a lipophilic emulsifier with an HLB value of approximately 4.7. Research and applications in biscuits include:

Shortening Replacement: Studies show that biscuits made with oleogels prepared with 12%-18% sorbitan monostearate exhibit similar hardness and color to shortening biscuits, with uniformly porous cross-sections .

Synergistic Antioxidant Effects: Sorbitan monostearate shows synergistic antioxidant effects when combined with mixed tocopherol concentrates, contributing to extended biscuit shelf life .

Texture Modification: In oleogel systems, sorbitan monostearate imparts appropriate hardness and crispness to biscuits .

1 Necessity of Compounding

In practical applications, single emulsifiers often cannot simultaneously meet all quality requirements of biscuit products. Compounding different emulsifiers can produce synergistic effects, achieving better results than using any single emulsifier alone . The advantages of compounding include:

• Complementary Mechanisms: Different emulsifiers have respective strengths in oil emulsification, gluten strengthening, starch binding, and antioxidant protection
• Precise HLB Control: By mixing high-HLB and low-HLB emulsifiers in proportion, the ideal balance required for the target system can be achieved
• Cost Optimization: Reasonable compounding can reduce overall costs while ensuring effectiveness

2 Classic Compounding Combinations

Monoglycerides Combined with SSL: Monoglycerides (low HLB) promote oil emulsification and dispersion, while SSL (medium HLB) strengthens gluten network and interacts with starch. Their combination simultaneously optimizes both processing properties and final quality of biscuits.

Lecithin Combined with DATEM: Lecithin provides natural emulsification function and antioxidant protection, while DATEM enhances dough structure and promotes loosening. This combination is suitable for clean-label product development.

Sucrose Esters Combined with Monoglycerides: Sucrose esters enable precise HLB value control, while monoglycerides provide basic emulsification function. Their combination allows optimization for specific oil phase systems.

3 Optimization of Addition Levels

Research indicates that the impact of emulsifiers on biscuit quality exhibits optimal addition ranges. For example:

• DATEM effectively reduces fat content while maintaining product quality in the range of 0.125%-0.5%
• Lecithin addition is typically controlled between 0.1%-2% of flour weight; excessive amounts may affect taste
• SSL optimal addition in reduced-fat biscuits is 0.5g

Emulsifiers significantly improve biscuit quality through multi-level mechanisms: during processing, they promote uniform oil emulsification and dispersion, improve dough mechanical properties, enhancing production efficiency and product consistency; during baking, they promote protein foaming and structure setting, forming loose porous crispy textures; during storage, they extend product shelf life through antioxidant effects and inhibition of starch retrogradation.

Different emulsifiers exhibit varied functional characteristics in biscuits due to differences in molecular structure and HLB values:

• Glycerol monostearate (HLB=3.8) primarily promotes oil emulsification, prevents oil exudation, and improves crispness
• Soy lecithin (HLB=4-7) as a natural emulsifier, possesses dual functions of emulsification and antioxidant protection
• Sodium stearoyl lactylate (HLB=8.3) improves demolding, appearance, and texture through dual action, while also providing anti-staling effects
• DATEM (HLB=8-9.2) as a dough strengthener, promotes loose structure formation and can reduce fat content
• Sucrose fatty acid esters (adjustable HLB) control starch gelatinization and retrogradation through precise HLB value regulation
• Sorbitan monostearate (HLB=4.7) shows potential for shortening replacement in oleogel systems

Looking forward, with increasing consumer demand for clean-label products, developing natural-source, high-efficiency emulsifiers has become a research hotspot . Meanwhile, achieving synergistic effects of emulsifiers through compounding technology and precise optimization of addition levels will remain an important direction for biscuit quality improvement.