The property of phospholipids in food systems that assists in the formation of stable foams

Foam structure is widely applied in aerated food products including baked goods, whipped cream, mousse, ice cream and aerated beverages. Many synthetic emulsifiers easily generate excessive, fragile foam with poor controllability. Excess unstable foam triggers overflow during processing, increases production loss and negatively affects finished product texture. Phospholipids exhibit unique low-foaming characteristics alongside the capacity to construct stable foam frameworks within food matrices. Instead of producing abundant uncontrollable foam, phospholipids form thin, elastic interfacial films at the gas-liquid interface, supporting uniform foam that maintains structural stability without rapid collapse. This paper compares the foaming defects of conventional surfactants, elaborates the molecular mechanism of phospholipids balancing foam quantity and foam stability, analyzes influencing factors of phospholipid foaming performance in different food environments, and discusses application strategies of phospholipids as foam regulators in diversified food production systems.

1. Foaming challenges brought by traditional emulsifiers in food processing

Numerous synthetic emulsifiers possess strong foaming capacity, yet their foaming behavior lacks controllability, creating multiple production difficulties.

Excessive foam generation. Vigorous stirring, homogenization and aeration lead to massive foam accumulation inside mixing tanks, causing material overflow, raw material waste and sanitation risks. Manufacturers have to pause production to eliminate foam, disrupting continuous production rhythm.

Poor foam durability. The formed foam membrane is thin and brittle. Tiny bubbles rapidly merge into large bubbles, and foam collapses within a short time. Unstable aeration results in inconsistent porosity, uneven volume and shortened shelf life of aerated food.

Sensitivity to formula components. High oil content, soluble salts and pH fluctuations easily break the foam film formed by synthetic emulsifiers, failing to maintain stable aeration under complex food formula conditions.

Adverse influence on product sensory quality. Thick persistent foam remaining in liquid beverages brings unpleasant bubbly taste, damaging the smooth mouthfeel expected by consumers.

Distinct from such high-foaming synthetic surfactants, phospholipids deliver balanced performance: they avoid excessive foaming during material mixing, while capable of forming durable foam structures when targeted aeration is required. This low-foaming yet stable foaming characteristic matches the diversified processing demands of modern food manufacturing.

2. Molecular mechanism of phospholipids realizing low foaming and stable foam formation

Phospholipid molecules are typical amphiphilic glycerophospholipids with hydrophilic polar heads and hydrophobic fatty acid chains. Their unique interfacial behavior determines special foaming properties.

(1) Interfacial film construction mechanism

When phospholipids migrate to the gas-liquid interface, molecules arrange orderly to form continuous interfacial films. Compared with single-chain synthetic surfactants, phospholipids have dual fatty acid chains. The formed interfacial membrane possesses higher elasticity and mechanical strength. The membrane can resist bubble coalescence and liquid drainage, effectively slowing foam collapse and improving foam stability.

(2) Reasonable surface tension adjustment limits excessive foam generation

Phospholipids moderately reduce system surface tension, yet their surface activity is weaker than high-foaming anionic surfactants. Under mechanical stirring without intentional aeration, they cannot support massive bubble nucleation, thus showing low foaming traits and preventing accidental foam surges in mixing and homogenization procedures.

(3) Viscosity regulation of continuous phase inhibits liquid drainage

Phospholipids interact with proteins, starch and other food macromolecules in the system, moderately increasing the viscosity around bubble walls. It slows the flow of liquid inside foam gaps, delays liquid drainage, and extends the survival time of microbubbles.

(4) Anti-coalescence effect between bubbles

The adsorbed phospholipid layer on the surface of bubbles produces steric hindrance. When two bubbles approach each other, the phospholipid film prevents direct fusion of bubble walls, maintaining uniform tiny bubble distribution and avoiding coarse porous structure caused by bubble merging.

3. Key factors affecting phospholipid foaming performance in food systems

(1) Phospholipid composition and modification degree

Natural soybean phospholipids and enzymatically modified phospholipids show different foaming behaviors. Enzymatic hydrolysis can adjust fatty acid chain length and hydrophilic-lipophilic balance, appropriately improving foaming ability. High phosphatidylcholine fractions are more conducive to forming elastic interfacial films and stable foam.

(2) System oil-water ratio

In high-oil food systems, phospholipids preferentially participate in emulsification of oil droplets, reducing the quantity available for gas-liquid interface film formation, showing more obvious low-foaming performance. In low-oil aqueous systems, phospholipids are easier to assemble on bubble surfaces to build stable foam.

(3) pH value and ion concentration

Metal ions and hydrogen ions change the charge state of phospholipid polar head groups. Appropriate ion concentration enhances interfacial film compactness; excessive ions will destroy the ordered arrangement of phospholipid molecules and weaken foam stability.

(4) Compound coordination with proteins and carbohydrates

Whey protein, gluten and gelatin can form composite interfacial films together with phospholipids. The composite membrane further strengthens foam structure, which is widely used in baked food and whipped dairy products.

4. Classification of application scenarios based on phospholipid low foaming and stable foaming characteristics

(1) Processing requiring low foaming priority

Liquid beverage production, syrup blending, paste filling and liquid premix processing. During stirring, filtration and pipeline transportation, phospholipids suppress undesired foam overflow. Meanwhile, phospholipids maintain basic emulsification functions without introducing extra defoamer, realizing clean-label formula design.

(2) Processing requiring controllable stable foam

Whipped cream, cake batter, mousse, ice cream and aerated confectionery. After targeted aeration, phospholipids form uniform and stable microfoam, supporting product volume retention, avoiding shrinkage after molding, and optimizing soft and fluffy texture.

(3) Compound food systems with alternating aeration and emulsification requirements

Frozen pastry fillings, composite cream sauces. Phospholipids emulsify oil and fat components, and control foam generation during mixing. When whipping is needed, they assist in forming stable foam to enrich taste layers.

5. Advantages of phospholipids over independent foaming agents and defoamers

Many formulas adopt separate foaming agents and defoamers to regulate foam, which increases additive types and raises formula complexity. Phospholipids integrate dual functions naturally. In the absence of forced aeration, it presents low foaming property to avoid processing obstacles; when aeration conditions are provided, it constructs elastic interfacial films to stabilize foam.

As natural food-derived ingredients, phospholipids comply with clean label trends. They simultaneously provide emulsification, nutrition and foam regulation effects, unlike purely functional chemical foam regulators with single performance. Moreover, phospholipids will not cause adverse flavor changes and do not bring peculiar aftertaste to food products.

6. Formula optimization suggestions for utilizing phospholipid foaming characteristics

Select suitable phospholipid types according to processing objectives. Choose natural composite phospholipids when low foaming is the primary demand; adopt moderately enzymatically modified phospholipids if stronger stable foaming capacity is required.

Match phospholipids with proteins to build composite interfacial films in aerated food, maximizing foam stability.

Control dosage range. Excessive phospholipid dosage may change system viscosity and shift foaming behavior; appropriate addition achieves balanced emulsification and foam regulation.

Coordinate technological parameters including stirring speed, homogenization pressure and aeration volume to give full play to phospholipid’s unique low foaming and stable foaming performance.

Excess uncontrollable foam or rapidly collapsing foam brings multiple quality and production obstacles to food manufacturing. Phospholipids own distinctive dual characteristics of low foaming and stable foam formation. Restricted by moderate surface activity, they avoid massive spontaneous foam generation during conventional mixing and transportation. Once aeration is applied, phospholipid molecules assemble at the gas-liquid interface to form elastic, tough interfacial films, suppress bubble merging and liquid drainage, and maintain long-term stable microfoam structure. This property enables phospholipids to serve as multifunctional foam regulators in diverse food systems, covering low-foaming liquid processing and aerated fluffy food production. Combined with natural origin, excellent emulsification and nutritional value, phospholipids become an ideal clean-label alternative to synthetic foam additives, providing flexible and reliable solutions for texture control of aerated food and stable operation of automated production lines.