From Yogurt to Bread: The “Invisible Guardian” Hidden in Your Food — Unveiling Food-Grade Disodium Phosphate (DSP)

Have you ever noticed how yogurt in supermarket refrigerators remains smooth and lump-free no matter how long it sits? Or how your breakfast bread stays fluffy and elastic when torn open? Or how bottled plant-based protein drinks show no signs of sedimentation or separation even after a week?

These “perfect conditions” in everyday foods aren’t solely thanks to the natural “talents” of the ingredients themselves. Often, they rely on a discreet yet essential backstage contributor — food-grade disodium phosphate (DSP).

It doesn’t add flavor, color, or aroma — but like a precise “master of balance,” DSP quietly adjusts the pH, stability, and texture of food, while also subtly enhancing its nutritional profile. Today, let’s uncover the mystery behind this “invisible guardian.”

I. What Is Food-Grade Disodium Phosphate (DSP)?

Disodium phosphate (DSP, chemical formula: Na₂HPO₄), with CAS numbers 7558-79-4 (anhydrous) and 10039-32-4 (dodecahydrate), is a functional phosphate compound widely used in the food, beverage, pharmaceutical, and industrial sectors.

Simply put, DSP is an inorganic compound composed of sodium and phosphate ions (Na₂HPO₄). Due to its molecular structure, it exists in two different forms, making it adaptable to various food processing needs:

Form	CAS No.	Appearance	Key Characteristics	Typical Applications
Anhydrous	7558-79-4	White powder	Fast-dissolving, high purity, but prone to clumping	Instant beverages, ready-to-eat soups, powdered foods
Dodecahydrate	10039-32-4	White crystals	Contains 12 crystal water molecules, stable, low hygroscopicity	Bakery production, humid storage environments, meat processing

In the international food additive system, DSP holds a dedicated identity — EU additive number E339 (ii). This designation means its safety and functionality have been verified by leading global regulatory authorities, and it is approved for widespread use in dozens of food categories including dairy products, baked goods, beverages, and processed meats.

II. From Lab Bench to Dining Table: How Did DSP Enter Everyday Foods?

The “debut” of DSP began with a simple yet pivotal chemical reaction:In the late 19th century, scientists first synthesized this white powder in the laboratory by neutralizing phosphoric acid (H₃PO₄) with sodium carbonate (Na₂CO₃).

Initially, due to its excellent pH buffering capacity and metal ion chelating ability, DSP was mainly used in industrial water treatment and electroplating.But by the mid-20th century, food scientists began to recognize its “special talents” in food applications:

• It stabilizes casein proteins in milk, preventing yogurt from curdling.

• It works synergistically with leavening agents to enhance dough rise, making bread fluffier and more uniform.

• It stabilizes colloidal systems in beverages, preventing sedimentation of plant proteins or fruit particles.

As a result, regulatory bodies such as the U.S. FDA, JECFA, and others began evaluating its safety and gradually incorporated DSP into their food additive approval lists.

Regulatory Milestones: From Regional Approval to Global Acceptance

Year	Country / Organization	Regulatory Event
1970s	JECFA (FAO/WHO)	Completed toxicological evaluation and added DSP to the food additive register
1980	U.S. FDA	Recognized as GRAS (Generally Recognized As Safe); permitted in foods (21 CFR §182.1778)
1995	European Union	Assigned additive number E339 (ii); classified as acidity regulator, stabilizer, and leavening agent
2010	China	Issued GB 25568-2010, establishing national standards for food-grade DSP
Ongoing	Japan, ASEAN countries, etc.	Included in national positive lists for use in dairy, bakery, meat products, etc.

III. The 3 Core Functional Powers of DSP:

How Does It “Protect” Our Food?

DSP has secured its place in the food industry thanks to three essential technical capabilities, each directly influencing the quality and stability of food:

🧪 Skill 1: pH Buffering — Creating a “Stable Environment” for Food

The “perfect condition” of many foods is highly sensitive to pH fluctuations:Yogurt may curdle if the pH is too low, bread may turn hard if the pH is too high, and beverages may oxidize or discolor if the pH isn't steady.

DSP acts as an “intelligent regulator”, using its dissociation equilibrium to stabilize the system’s pH:

When the system becomes acidic, HPO₄²⁻ binds excess H⁺;

When it becomes alkaline, HPO₄²⁻ releases H⁺.

The result is a weakly alkaline buffer environment with a pH around 9.0–9.4.

This enables DSP to:

• Prevent casein precipitation in yogurt caused by sudden pH drops

• Stabilize dough pH in bread, enhancing gluten network strength

• Prevent phase separation in plant-based protein beverages due to pH instability

🧪 Skill 2: Nutritional Fortification — Supplying “Essential Elements”

DSP is not only a regulator but also a “nutrient provider.”It contains phosphorus and sodium, both essential minerals for human health:

• Phosphorus is vital for bone development and energy metabolism

• Sodium helps maintain fluid and electrolyte balance

More importantly, DSP can form soluble complexes with calcium and magnesium, improving the intestinal absorption of these minerals.Therefore, in infant formulas and functional beverages, DSP is often used as a nutritional enhancer.

🧪 Skill 3: Heat Resistance — Withstanding the “Trial by Fire”

During food processing steps such as baking or sterilization (e.g., UHT milk), temperatures often exceed 100°C, causing many ingredients to degrade.

DSP, however, is highly heat-resistant and remains stable under such conditions, allowing it to:

• Prevent structural collapse in bread caused by sudden temperature spikes

• Withstand heat shock during sterilization and protect milk proteins from denaturation

• Help canned foods retain their original texture and flavor even after extended heating

IV. Is It Safe? What Do Global Authorities Say?

This is perhaps the question most readers care about —Is DSP safe for consumption?The answer is: Yes, when used within the limits set by food regulations, DSP is considered safe.

✅ Conclusions from Authoritative Bodies

• EFSA (European Food Safety Authority):

  
  

  No evidence of carcinogenicity, mutagenicity, or teratogenicity.

  The acceptable daily intake (ADI) is set at 0–70 mg/kg body weight, expressed as phosphorus.

• FDA (U.S. Food and Drug Administration):

  
  

  Classified DSP as GRAS (Generally Recognized As Safe), stating there are no safety concerns under normal usage levels.

• JECFA (Joint FAO/WHO Expert Committee on Food Additives):

  
  

  Conducted a comprehensive toxicological review and confirmed its metabolic pathway —

  DSP breaks down into phosphate and sodium ions in the body,

  is excreted naturally through urine, and does not accumulate in the human system.

✅ Global Usage Standards

To ensure its safety in foods, many countries have established strict regulations regarding DSP’s purity and impurity limits:

Region / Authority	Key Regulatory Requirements
China	GB 1886.329-2021: Purity ≥ 98.0%, Lead ≤ 2 mg/kg, Arsenic ≤ 3 mg/kg
European Union	E339 (ii): Fluoride ≤ 10 mg/kg; microbiological criteria must be met
United States	GRAS (21 CFR §182.1778): Must meet food-grade purity specifications

V. Anhydrous vs. Dodecahydrate: Which One Should You Choose?

Disodium phosphate (DSP) exists in two forms, and each is suited to different applications.Choosing the wrong form may affect product performance and processing efficiency.

Property	Anhydrous (Na₂HPO₄)	Dodecahydrate (Na₂HPO₄·12H₂O)
Molecular Weight	142 g/mol	358.14 g/mol
Appearance	White powder, prone to caking	White crystalline granules, prone to weathering
Solubility (20°C)	77 g/100 mL	77 g/100 mL (slower dissolution rate)
Loss on Drying	≤ 2.0%	Approx. 51% (due to crystal water)
Typical Applications	Foods requiring rapid dissolution (e.g., beverages)	Humid storage or mass production environments (e.g., baking)

VI. Future Outlook: Will DSP Become Even More “Capable”?

As the food industry shifts toward health-conscious and functional formulations, the role of DSP is also evolving:

• A New Role in Salt Reduction:

  When blended with potassium chloride, DSP can help reduce overall sodium content while maintaining food stability — making it ideal for “low-sodium” product development.

  
  

• A Key Ally for Plant-Based Foods:

  Plant proteins (e.g., oat or peanut proteins) often suffer from low colloidal stability. DSP can help form more stable colloidal systems, improving the texture and consistency of plant-based milks and meats to closely resemble traditional foods.

  
  

• Toward Greener Manufacturing:

  While DSP is currently produced primarily via chemical synthesis, future processes may include eco-friendly methods, such as extracting DSP from by-products of microbial fermentation, helping to reduce energy consumption and environmental impact.

  
  

📗 Conclusion

Disodium phosphate (DSP) is a versatile phosphate salt that plays a vital role in the food industry through its pH buffering, system-stabilizing, and nutritional enhancement capabilities.

Its value lies not only in its adaptability across various food applications, but also in its ability to balance safety with practicality — making it an indispensable foundation in modern food processing.

DSP is like an “invisible guardian,” quietly supporting your meals each day:From the yogurt you drink in the morning, the bread you eat at lunch, the plant-based drink in the afternoon, to the ready-to-eat ham at dinner — it works silently to preserve the quality, safety, and nutrition of your food.

So next time you check a product label and see “disodium phosphate” or “E339 (ii)”, you’ll know more about the unsung hero behind your everyday meals — a perfect example of the “fine art of balance” in food science.

🏁 Final Message from Kelewell

At Kelewell, we understand that safe and compliant ingredients are the cornerstone of food innovation.When it comes to food-grade Disodium Phosphate (DSP), we apply strict quality standards to every batch we deliver.

Whether it’s functioning as a pH buffer to maintain the smoothness of dairy products, a stabilizer to ensure beverage uniformity, or a nutrient enhancer to support mineral fortification in functional foods — our DSP provides consistent, reliable, and globally compliant performance across baking, dairy, plant-based, and many other applications.

We welcome all technical discussions, regulatory documentation requests, and custom packaging inquiries to fully support your product development and market access.

📩 For detailed specifications, samples, or tailored solutions, feel free to contact us anytime —Kelewell, advancing every step of food innovation with you.