What is E640?

Complete guide to understanding E640 (Glycine and its Sodium Salt) in your food

The Quick Answer

E640 is glycine and its sodium salt, a simple amino acid used as a flavor enhancer and nutrient supplement in food.

Glycine is one of the simplest and smallest amino acids found naturally in all proteins in human bodies and other living organisms.

It’s used in food to mask bitter aftertastes of sweeteners, enhance overall flavor, and provide nutritional benefits, particularly for bread production.

What Exactly Is It?

E640 is glycine (the simplest amino acid) and/or its sodium salt.

Glycine, scientifically called aminoacetic acid, is the smallest and simplest of all amino acids—the building blocks of proteins. It consists of just a hydrogen atom, a carboxyl group, and an amino group attached to a central carbon.

Your body naturally produces glycine and uses it extensively in proteins, cartilage, skin, and connective tissue. You consume glycine every time you eat protein-containing foods like meat, poultry, fish, eggs, or legumes.

Two forms of E640:

• E640(i) Glycine: The pure amino acid, white crystalline powder, odorless, with a slightly sweet taste
• E640(ii) Sodium glycinate: Glycine bonded with sodium, used in specific applications where the sodium salt form is preferred

Manufacturing sources:

• From gelatin: The most common source—gelatin is hydrolyzed (broken down) to extract glycine
• From sugar cane: Fermentation or chemical synthesis using sugar as a starting material
• Synthetic production: Laboratory synthesis of the amino acid
• From protein hydrolysates: Breaking down various protein sources to extract glycine

Where You’ll Find It

E640 appears in various processed foods:

• Bakery products and bread
• Desserts and confectionery
• Beverages and drinks
• Jams, preserves, and fruit preparations
• Salted vegetables and pickled products
• Sauces, gravies, and condiments
• Vinegar and fermented products
• Margarine and butter spreads
• Cream cheese and processed cheese products
• Alcoholic beverages (wine, spirits)
• Dietetic products and nutritional supplements

E640 is particularly common in baked goods, where it serves multiple functions: as a nutrient for yeast fermentation, as a flavor enhancer to round out taste, and as a stabilizer.

Why Do Food Companies Use It?

E640’s primary function is flavor enhancement, but it serves multiple purposes in food production.

Food manufacturers use glycine and sodium glycinate for specific advantages:

• Aftertaste masking: Masks bitter or unpleasant aftertastes, particularly from artificial sweeteners like saccharin
• Flavor rounding: Adds a subtle sweetness that rounds out and balances overall flavor profiles
• Mildly sweet taste: Its inherent slight sweetness can reduce need for added sugars or sweeteners
• Yeast nutrition: Provides essential nitrogen for yeast fermentation in bread production
• Bread enhancement: Improves bread texture, rise, and overall quality during fermentation
• Moisture retention: Helps retain moisture in cream cheese, margarine, and processed foods
• pH buffering: Stabilizes pH in acidic products like vinegars and sauces
• Acid correction: Used as an acid buffer and corrector in wines and beverages
• Nutritional fortification: Adds amino acid content to dietetic and supplemental products
• Stabilization: Helps maintain consistency and texture in complex food systems

The cost-effectiveness of E640—particularly its dual roles as both a functional ingredient and flavor modifier—makes it attractive to food manufacturers.

Is It Safe?

E640 is approved by major regulatory authorities and is considered safe at approved use levels.

Both the FDA and EFSA have authorized its use, and it appears on approved additives lists worldwide.

Safety profile:

• FDA recognizes E640 as Generally Recognized As Safe (GRAS)
• EFSA has evaluated E640 and found no safety concerns at reported use levels
• No numerical Acceptable Daily Intake (ADI) was established—indicating no need for specific safety limits
• No known harmful effects at normal consumption levels
• The body metabolizes E640 identically to glycine obtained from protein foods
• Glycine is essential for proper body function and is synthesized naturally by the body
• No documented widespread adverse effects from normal food consumption
• Generally considered one of the safest food additives

Important note about sources:

While E640 itself is safe, its source matters for dietary restrictions:

• If derived from animal gelatin: NOT suitable for vegans, and potentially not for vegetarians depending on interpretation
• If derived from animal gelatin: May not comply with Muslim Halal requirements or Jewish Kosher requirements (depending on animal source)
• If synthetically produced or derived from plant sources: Generally acceptable to all dietary groups

Natural vs Synthetic Version

E640 is available in both naturally-derived and synthetically-produced forms:

Natural sources:

• From animal gelatin—historically the most common source
• From protein hydrolysates of animal or plant origin
• From fermentation of plant sugars using microorganisms

Synthetic production:

• Laboratory synthesis creates chemically identical glycine
• Often starts with simple chemical precursors
• Can produce pure glycine indistinguishable from naturally-derived forms

Chemically identical: Regardless of source, glycine is a simple molecule. Your body cannot distinguish between glycine from gelatin, plant sources, or synthetic production—they’re all metabolized identically.

Natural Alternatives

Want to avoid E640 or use other flavor enhancers?

Some alternatives include:

• Monosodium glutamate (MSG, E621) – More potent flavor enhancer; controversial in some circles
• Natural vanilla or vanilla extract – Masks bitter aftertastes; more expensive
• Citric acid (E330) – Balances and brightens flavors; acidic
• Natural sweeteners – Stevia, monk fruit—round flavor differently
• Herbs and spices – Traditional flavor enhancers; variable effects
• Yeast extracts – Natural alternatives for bread fermentation
• No additive approach – Accept less perfectly rounded flavors in favor of cleaner labels

Most alternatives don’t replicate E640’s specific function of masking bitter aftertastes from artificial sweeteners, making E640 nearly irreplaceable in diet beverage formulations.

The Bottom Line

E640 (glycine and its sodium salt) is a simple amino acid used as a flavor enhancer and nutrient in food.

It’s found commonly in baked goods, desserts, beverages, and processed foods.

Regulatory bodies including the FDA and EFSA have determined E640 is safe for consumption at approved use levels, with no specific safety limits needed.

The body processes E640 identically to glycine obtained from eating protein foods—it’s not a foreign chemical.

However, the key consideration is the source: If E640 is derived from animal gelatin, it’s unsuitable for vegans and strict vegetarians. Synthetic or plant-based sources are also available but not always clearly labeled.

For consumers with dietary restrictions related to animal products, contacting manufacturers to verify E640’s source is the best approach, as product labels rarely specify whether it’s animal-derived or synthetic.