E639 - DL-alanine

At a glance

• DL-alanine is a 1:1 mixture of the D- and L- forms of the amino acid alanine.
• It is used mainly as a flavor enhancer or flavoring to soften sharp tastes and support sweetness or umami.
• You may find it in seasonings, beverages, soups, sauces, and confectionery.
• It is typically manufactured by chemical synthesis and used in very small amounts.
• Label names: DL-alanine, E639.

Why is DL-alanine added to food?

Food makers add DL-alanine to improve flavor in a gentle way. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) has evaluated alanine (including DL-alanine) as a flavoring agent in foods.¹ In the European Union (EU), DL-alanine is assigned the code E639 and appears on the Union list of approved food additives.² In the United States (US), it is permitted as a synthetic flavoring substance when used in line with Good Manufacturing Practice (GMP), which means the minimum amount needed to achieve the intended flavor effect.³

What foods contain DL-alanine?

You are most likely to see DL-alanine in flavored foods where a soft sweetness or “rounding” of taste is wanted. In the US, it may be added to foods as a flavoring substance, provided it is used according to GMP.³ In the EU, E639 is authorized only in the food categories and conditions listed in Annex II to Regulation (EC) No 1333/2008.² On ingredient lists, look for “DL-alanine” or “E639.”

What can replace DL-alanine?

Other flavor enhancers can serve similar roles, depending on the recipe:

• For mild sweetness and smoothing: glycine
• For umami boost: monosodium glutamate
• For savory depth in combination: disodium inosinate, disodium guanylate, or calcium diglutamate

How is DL-alanine made?

DL-alanine is the racemic (50:50) mixture of the two mirror-image forms of alanine, defined as a food additive with specific purity criteria in EU specifications.⁴ Commercially, the racemic form is commonly produced by chemical synthesis; a typical route is the Strecker synthesis from an aldehyde, ammonia, and hydrogen cyanide, followed by hydrolysis.⁵

Is DL-alanine safe to eat?

Based on its evaluation as a flavoring agent, JECFA concluded there is “no safety concern” for alanine (including DL-alanine) at current levels of use in food.¹ In the EU, E639 must meet identity and purity criteria set in Commission Regulation (EU) No 231/2012, which also limits impurities.⁴ In the US, its permitted use as a flavoring substance is regulated under FDA rules and limited by GMP, meaning only small amounts are used.

Does DL-alanine have any benefits?

From a food technology view, DL-alanine can help mask harsh notes, smooth acidity or saltiness, and add a slight sweetness, giving formulators fine control over taste.⁵ These functions can help keep flavors balanced without introducing a strong new flavor.

Who should avoid DL-alanine?

Most people do not need to avoid DL-alanine because the amounts used are very small. If you have a medical condition that requires a protein- or amino acid–restricted diet, ask a healthcare professional about your specific needs. Foods for infants and very young children also follow stricter additive rules in many places, so E639 is uncommon in those products.

Myths & facts

• Myth: “DL-alanine is the same as MSG.”
  Fact: They are different compounds. DL-alanine is an amino acid flavoring; MSG is the sodium salt of glutamic acid and a well-known umami enhancer.
• Myth: “E-numbers are always unsafe.”
  Fact: An E-number means the additive was evaluated and authorized in the EU with conditions of use.
• Myth: “DL-alanine adds a strong flavor.”
  Fact: It works subtly, mainly smoothing and rounding existing flavors.

DL-alanine in branded foods

You may see DL-alanine in ingredient lists for seasonings, powdered drink mixes, confectionery, soups, or sauces. Look for “DL-alanine” or “E639.” Because it is used at low levels for fine flavor tuning, it may not be present in many everyday products, and some brands may prefer alternatives like glycine or monosodium glutamate.

References

Footnotes

1. Alanine and L-alanine — JECFA, WHO Food Additives Series 42. https://inchem.org/documents/jecfa/jecmono/v42je03.htm ↩ ↩²

2. Regulation (EC) No 1333/2008 on food additives (Union list, Annex II) — EUR-Lex. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:02008R1333-20161025 ↩ ↩²

3. 21 CFR 172.515 Synthetic flavoring substances and adjuvants — FDA/eCFR. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-172/subpart-F/section-172.515 ↩ ↩²

4. Commission Regulation (EU) No 231/2012 (specifications for food additives) — EUR-Lex. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32012R0231 ↩ ↩²

5. Alanine — PubChem (NIH). https://pubchem.ncbi.nlm.nih.gov/compound/5950 ↩ ↩²