What is E575?

Complete guide to understanding E575 (Glucono Delta-Lactone) in your food

The Quick Answer

E575 is glucono delta-lactone (GDL), a naturally occurring cyclic ester of gluconic acid made from glucose fermentation.

It’s used in food primarily as an acidity regulator, preservative, leavening agent (in baking), sequestrant, and—most famously—as a coagulant for making tofu.

E575 is unique because it’s one of the few food additives that actually occurs naturally in honey, fruit juices, and wine—making it one of the most “natural” additives available.

📌 Quick Facts

Category: Acidity regulator, preservative, leavening agent, sequestrant, coagulant
Chemical form: Cyclic ester (lactone) of gluconic acid
Also known as: GDL, gluconolactone, D-glucono-1,5-lactone, delta-gluconolactone
Found in: Tofu, mozzarella and cheese, canned vegetables, pasta, dry sausages and cured meats, baked goods, beverages
Safety: FDA GRAS approved, EFSA approved, JECFA approved
Acceptable Daily Intake (ADI): “Not specified” set by JECFA in 1998; “quantum satis” principle applies (use as much as needed)
Natural occurrence: Found naturally in honey, fruit juices, and wine
Source: Fermented glucose (corn starch is primary source)
Physical form: Fine white, odorless crystalline powder
Taste: Slightly sweet taste; dissolves slowly in water to create mild acidification
Key property: Controlled, gradual pH reduction (self-regulating acidity)
Melting point: 150-153°C (shows stability at high temperatures)
Dietary restrictions: Vegan, vegetarian, kosher, halal, gluten-free, GMO-free (when from plant sources)

What Exactly Is It?

E575 is glucono delta-lactone (GDL), a naturally occurring lactone (cyclic ester) of gluconic acid.

Imagine gluconic acid curling into a tight circle—that’s essentially what happens when gluconic acid forms a lactone ring. This ring structure is what makes E575 unique and gives it different properties from straight gluconic acid.

When E575 dissolves in water, the ring slowly opens, gradually releasing gluconic acid—creating a controlled, self-regulating acidification process.

Chemical formula: C₆H₁₀O₆

Molecular weight: 178.14 g/mol

CAS Number: 90-80-2

Natural occurrence:

E575 is not purely synthetic. It occurs naturally in:

• Honey
• Fruit juices (especially apple juice)
• Wine
• Fermented foods

How it’s made:

• Step 1 – Glucose source: Corn starch is the primary source (fermentable glucose)
• Step 2 – Fermentation or oxidation: Glucose is converted to gluconic acid via fermentation or oxidation
• Step 3 – Crystallization: Gluconic acid solution is cooled, and GDL crystallizes directly from the aqueous solution
• Step 4 – Purification: Crystals are filtered and purified

Key distinction: E575 is the lactone form of gluconic acid (E574). In aqueous solution, there’s an equilibrium between the lactone (GDL) and the open-chain gluconic acid (55-66% gluconic acid, 34-45% lactone forms).

Where You’ll Find It

E575 appears in diverse food products:

• Tofu (traditional coagulant; creates silky texture)
• Mozzarella and ripened cheeses
• Canned or bottled vegetables
• Fresh (pre-cooked) pasta
• Biscuits and rusks for infants and young children
• Dry-cured sausages and processed meats
• Baked goods (bread, cakes, pastries)
• Meat emulsions (frankfurters, pâté, luncheon meat)
• Cheese products
• Frozen desserts
• Yogurt and dairy products
• Sauces and condiments
• Salads and dressings
• Fermented foods and pickles

E575 is particularly common in traditional Asian foods (especially tofu), European processed meats (especially German and Italian sausages), and artisanal cheese-making.

💡 Pro Tip: Check labels on tofu, cheese, canned vegetables, dry sausages, baked goods, and infant biscuits for “E575” or “glucono delta-lactone” or “GDL”. It’s particularly common in products emphasizing “natural” processing, traditional preparation methods, or minimal additive lists—because it IS naturally occurring and functions through a natural process.

Why Do Food Companies Use It?

E575’s primary function is controlled pH reduction through gradual, self-regulating acidification.

Food manufacturers use glucono delta-lactone for multiple advantages:

• Controlled acidification: Creates gradual, predictable pH reduction (self-regulating—doesn’t overshoot)
• Tofu coagulation: Curdles soy milk into silky tofu without bitter taste or protein loss
• Curing accelerator: Speeds fermentation in sausages while ensuring food safety
• Cheese/dairy gelling: Coagulates milk for cheese production without harsh flavor
• Preservative effect: Lowers pH to prevent bacterial growth and spoilage
• Leavening agent: In bakery, provides controlled acid for baking soda reaction
• Color stabilization: In meat products, stabilizes myoglobin color (red color in sausage)
• Chelating agent: Binds metal ions that cause discoloration
• Buffering capability: Maintains desired pH stability
• Water retention: Improves texture and moisture content in meat products
• Flavor improvement: Adds slight sweetness and balances flavor
• Taste enhancement: Enhances savory flavors in meat and cheese products
• Shelf life extension: Prevents microbial growth and spoilage
• Safety assurance: Ensures rapid pH drop for pathogenic organism control (Clostridium botulinum prevention)
• Natural image: Occurs naturally in honey and fruits—appeals to “clean label” consumers
• Regulatory advantages: Often approved in systems where other additives are restricted

Unique advantage: E575 provides what’s called “controlled release acidulation”—the pH doesn’t drop suddenly (like vinegar would) but instead drops gradually and predictably as the lactone ring slowly opens. This is ideal for processes where the timing and extent of acidification are critical (like making tofu or fermented sausages).

Is It Safe?

E575 is one of the safest food additives, particularly because it’s naturally occurring.

Approval status:

• FDA approved: Generally Recognized As Safe (GRAS) as direct human food ingredient; approved as a curing agent, leavening agent, pH control agent, and sequestrant
• EFSA approved: Listed in Commission Regulation (EU) No 231/2012 as authorized food additive; classified in “Group I” with “quantum satis” use (no specific limits)
• JECFA approved: ADI “not specified” (1998) for gluconic acid and its salts and derivatives
• Food Standards Australia New Zealand: Approved with code 575
• UK Food Standards Agency: Categorized as “Others” approved additive
• International approval: Approved in virtually all countries worldwide

Safety profile:

• ADI: “Not specified” by JECFA—indicating no safety concerns
• Natural occurrence: Found in honey, fruit juices, and wine—supporting natural safety
• No toxicity: No documented toxicity at food use levels; decades of safe use
• No carcinogenicity: No evidence of cancer-causing potential
• No reproductive effects: Safe for pregnancy and breastfeeding
• Metabolism: Metabolized as carbohydrate; completely metabolized like glucose
• Energy content: Provides approximately 1 calorie per gram (like carbohydrates)
• Biodegradability: Readily biodegradable in environment
• Infant safety: Approved for use in infant biscuits and infant food
• No documented adverse effects: No widespread adverse effects documented at food use levels

Special populations:

• Infants and young children: Safe for use in infant biscuits and infant food—the most strictly regulated food categories
• Pregnant women: Safe; provides minimal acidity contribution to overall diet
• People with sodium restrictions: Sodium-free alternative to salt for acidification
• Vegan and vegetarian consumers: Completely suitable; plant-based fermentation product

✓ Safety Summary: E575 is exceptionally safe because it naturally occurs in foods you likely consume regularly (honey, fruit juice, wine). FDA, EFSA, and JECFA all approve it without specific limits. Approval for infant biscuits—the most strictly regulated food products—demonstrates high safety confidence for vulnerable populations.

Natural vs Synthetic Version

E575 is naturally derived and produced through fermentation:

Source and production:

• Starting material: Glucose from corn starch (plant-derived)
• Production method: Fermentation (natural process) or oxidation (more processed)
• Natural occurrence: Also naturally present in honey, fruit juices, wine
• Final product: Chemically identical regardless of production method

Perceived “naturalness”: E575 is one of the most “natural” food additives available because it genuinely occurs in nature. Unlike synthetic additives that don’t exist in nature, E575 already exists in honey and fruit—making it a legitimate “natural” additive.

Vegetarian/vegan/kosher/halal status: E575 is fully vegetarian, vegan, kosher, and halal (when produced from plant sources).

Natural Alternatives

Want to avoid E575 or looking for alternative acidifiers?

Some alternatives include:

• Gluconic acid (E574) – The parent compound; same function; different form
• Citric acid (E330) – Alternative acidifier; more rapid acidification; tart taste
• Tartaric acid (E334) – Alternative acidifier; naturally occurring; different properties
• Lactic acid (E270) – Alternative acidifier; occurs in fermented foods; different flavor profile
• Acetic acid (E260) – Vinegar; strong acidifying agent; pronounced taste
• Malic acid (E296) – Apple acid; alternative acidifier; fruity note
• Natural fermentation: Use traditional souring methods (longer process, less controlled)
• Vinegar or lemon juice: For some applications; different flavor impact
• Salt brining: For preservation; different mechanism and flavor

For tofu making specifically: Traditional alternatives include nigari (magnesium chloride), gypsum (calcium sulfate), or other salts—but these create different tofu textures. E575 creates silky tofu.

The Bottom Line

E575 (glucono delta-lactone) is a naturally occurring food additive used primarily as a controlled-release acidifier and coagulant.

It’s found in tofu, cheese, canned vegetables, dry sausages, and baked goods—where it provides gradual, predictable pH reduction or creates desired texture through coagulation.

E575 is approved by the FDA, EFSA, JECFA, and virtually all regulatory bodies worldwide.

Key advantages: E575 is one of the safest food additives because it naturally occurs in honey and fruit juices, biodegrades readily, is approved for infant food, and has decades of safe use without documented adverse effects. It’s particularly valued for its “controlled release” nature—providing gradual, self-regulating acidification that can’t overshoot.

Consumer perception: For health-conscious consumers, E575 is actually a positive indicator in food labels. It demonstrates the manufacturer used a gentle, naturally-occurring acidifier rather than synthetic alternatives.

E575 is especially recommended for anyone making tofu at home—it provides reliable, consistent results with superior texture compared to many alternatives, and it’s completely safe and natural.

What is E575? – Complete guide to understanding Glucono Delta-Lactone in your food