GLYCINE

CAS: 56-40-6 FLAVOR ENHANCER, FLAVORING AGENT OR ADJUVANT, NUTRIENT SUPPLEMENT

Glycine (CAS 56-40-6) is a non-essential amino acid used in foods as a flavor enhancer, flavoring agent, and nutrient supplement. It is permitted for direct addition to food under specific FDA regulations and has been evaluated by the Joint FAO/WHO Expert Committee on Food Additives with no safety concerns at current intake levels.

What It Is

Glycine is a simple amino acid with the chemical designation aminoacetic acid, identified by CAS number 56-40-6. It is one of the 20 proteinogenic amino acids and is the smallest of them, distinguished by its single hydrogen side chain. Industrially produced glycine is a white crystalline solid with a mildly sweet taste and high water solubility. It is used in the food industry for its multifunctional properties, primarily as a flavor enhancer, flavoring agent or adjuvant, and as a nutrient supplement. Glycine is also recognized in regulatory frameworks such as the United States Code of Federal Regulations, where it appears in specific sections defining its permitted use for direct addition to food, including as a masking agent in beverages and as an amino acid nutrient under prescribed conditions. These regulatory designations align with its technical functions, supporting its inclusion in various formulations for sensory, nutritional, and functional purposes. JECFA, a joint expert committee of the Food and Agriculture Organization (FAO) and the World Health Organization (WHO), has evaluated glycine and classified it within a flavoring functional class, providing context for its international food additive evaluation.

How It Is Made

Glycine used in food additive applications is typically manufactured by chemical synthesis rather than extraction from natural sources. Standard industrial processes involve the amination of chloroacetic acid with ammonia to produce glycine and hydrochloric acid, as well as variations of the Strecker amino acid synthesis. These methods yield high-purity glycine suitable for use in food-grade or technical applications. Following synthesis, glycine is purified to meet specifications such as those outlined in the Food Chemicals Codex, ensuring it meets criteria for identity, purity, and safety before being incorporated into food products. Food-grade glycine undergoes quality control steps to confirm compliance with regulatory and industry standards, which often specify impurity limits, solubility characteristics, and absence of harmful contaminants. Manufacturers operate under good manufacturing practice (GMP) guidelines to ensure consistent quality and safety of glycine in its various commercial forms. The production infrastructure for glycine reflects its widespread use in food, beverages, and dietary supplements, where controlled manufacturing supports reliable performance as a flavor enhancer or nutritional ingredient.

Why It Is Used In Food

Glycine is incorporated into food formulations for several practical reasons related to its technical functions. As a flavor enhancer and flavoring agent, it modulates taste profiles by contributing mild sweetness and enhancing desired savory notes, while helping reduce certain unpleasant sensory attributes such as bitterness. It serves as a nutrient supplement by contributing amino acid content to fortified foods and beverages, offering functionality in product lines that emphasize protein content or nutritional balance. Additionally, glycine functions as a masking agent in specific applications, such as reducing a bitter aftertaste in saccharin-containing beverages, where its inclusion can improve consumer acceptance. The use of glycine in nutritional supplements is linked to its role as one of the constituent amino acids of proteins, enabling formulators to deliver targeted amino acid contributions in specialized products. The combination of flavor enhancement and nutritional supplementation makes glycine versatile in product development, supporting a wide range of applications from savory foods to fortified beverages and nutrition-focused formulations.

Adi Example Calculation

An illustrative calculation for acceptable daily intake is typically structured around a hypothetical ADI value expressed in milligrams per kilogram of body weight. However, for glycine, a specific numeric ADI was not assigned by the JECFA evaluation for its use as a flavoring agent, as authoritative evaluation concluded that intake at current levels does not pose a safety concern. Therefore, applying a conventional ADI calculation for glycine is not appropriate in this context, and no specific numeric example is presented here. Instead, the principle of ADI calculations remains useful for understanding how regulators assess additive safety: a numerical ADI, if established, would be multiplied by body weight to estimate a lifetime daily intake threshold for a given individual. In the absence of a defined numeric ADI for glycine’s additive use, such calculations are not applicable, and glycine intake is contextualized within broader dietary amino acid exposure rather than an additive-specific ADI framework.

Safety And Health Research

Safety evaluations of glycine focus on its presence as a common dietary amino acid and its functional use as a food additive. JECFA’s evaluation classified glycine as a flavoring agent and noted that exposure from typical food uses does not raise safety concerns at current intake levels, reflecting its status as a normal component of dietary protein rather than a compound with inherent toxicity. Regulatory assessments emphasize that glycine’s safety in food use hinges on compliance with conditions of use and purity standards established in regulatory texts. Toxicological considerations include reviewing available data on general toxicity, metabolism, and exposure, though specific hazard endpoints such as genotoxicity or chronic toxicity are contextualized within its widespread occurrence in the diet. It is important to frame safety research within the context of additive use levels, recognizing that glycine is consumed in greater quantities through protein-containing foods than through its use as an additive. This perspective reinforces that safety evaluations consider both endogenous and exogenous sources, with regulatory and expert bodies applying risk assessment frameworks appropriate for food additives. Ongoing monitoring and research may inform future assessments, but current authoritative evaluations support glycine’s safety under established conditions of use.

Regulatory Status Worldwide

In the United States, glycine is recognized within the Code of Federal Regulations under specific food additive sections that permit its direct addition to food when meeting defined conditions of use and purity specifications. For example, 21 CFR 172.812 identifies glycine as a permitted additive for technological purposes such as masking bitter aftertaste in beverages and stabilizing mono- and diglycerides when meeting Food Chemicals Codex specifications. Additionally, 21 CFR 172.320 includes glycine among individual amino acids allowed as nutrients in foods, subject to compliance with defined compositional limits. These regulatory designations confirm that glycine’s use in food is contingent upon adherence to prescribed conditions to ensure safety under intended uses. JECFA, an international expert committee under FAO and WHO, evaluated glycine in 2004 and indicated that it presents no safety concern at current levels of intake when used as a flavoring agent, classifying it within an appropriate functional group without assigning a numerical acceptable daily intake. Regulatory frameworks in other regions may differ, and inclusion in specific additive lists or numbering schemes such as INS or E-numbers may vary, with differences reflecting regional assessments and use patterns. Manufacturers must consider applicable regulatory requirements in each market to ensure compliance when using glycine in food products.

Taste And Functional Properties

Glycine exhibits a mildly sweet taste that is less intense than traditional sweeteners, contributing to its selection as a flavor modifier in food and beverage applications. Its taste profile helps create a more balanced sensory experience, particularly in formulations where delicate sweetness or rounding of other flavors is desired. In addition to taste, glycine contributes functional properties linked to its solubility and reactivity, such as assisting in pH buffering and stabilizing formulations where pH balance influences texture or flavor expression. Its water solubility enhances its compatibility with aqueous food systems, including beverages and sauces, where it disperses uniformly. Glycine is also stable under typical processing conditions, enabling its inclusion in a variety of product categories without significant degradation. These functional properties are part of the rationale for its use as an ingredient that contributes more than flavor modulation alone, supporting both sensory and technical requirements in food formulation. Manufacturers select glycine for its combined taste and functional attributes when designing products to meet specific sensory and performance targets.

Acceptable Daily Intake Explained

An acceptable daily intake (ADI) represents an estimate of the amount of a substance that can be consumed daily over a lifetime without appreciable health risk, expressed per kilogram of body weight. For certain food additives, ADIs are established based on toxicological data and regulatory evaluations. In the case of glycine, JECFA’s evaluation for its use as a flavoring agent did not assign a numerical ADI, instead indicating no safety concern at current intake levels, reflecting its nature as a macronutrient and a normal component of protein. As a result, glycine’s regulatory context does not include a specific ADI value tied directly to its additive use, but rather positions its intake relative to typical dietary amino acid exposure. This distinction underscores that ADIs are tools for evaluating substances with defined toxicity thresholds, and compounds like glycine that are inherently part of normal human nutrition may not require a separate numeric ADI for regulatory purposes. It is important to interpret regulatory evaluations in the context of overall dietary exposure and to understand that ADI frameworks apply differently depending on the compound’s nutritional role and safety profile.

Comparison With Similar Additives

Glycine shares functional similarities with other amino acids used in food formulation, including alanine and glutamic acid, which can also contribute to taste modulation and nutritional enhancement. Alanine, another amino acid with a mildly sweet taste, may be used to impart sweetness and complement flavor profiles in similar applications, though its sensory impact differs from glycine’s subtle sweetness and masking properties. Glutamic acid, known for its strong umami taste, serves as a potent flavor enhancer distinct from glycine’s more balanced taste influence. Both alanine and glutamic acid appear in regulatory lists of permitted amino acids for nutrient supplementation and flavoring applications under defined conditions. Comparisons with other technical enhancers such as nucleotides or yeast extracts highlight differences in potency and sensory outcomes; nucleotides often synergize with amino acids like glutamic acid to enhance umami, whereas glycine’s role centers on subtle sweetness and bitterness reduction. Understanding these distinctions helps formulators select appropriate combinations of additives to achieve desired taste and functional objectives in food products, recognizing that each compound’s sensory and technical properties contribute uniquely to overall formulation performance.

Common Food Applications Narrative

Glycine finds application across a range of food and beverage categories due to its versatility as a flavor enhancer, flavoring agent, and nutrient supplement. In beverage formulations, glycine can be used to offset bitter notes and contribute a subtle sweetness, particularly in manufactured beverages and fortified drinks where a harmonious flavor profile is important. Its use in savory foods such as soups, sauces, and meat-based products supports enhanced umami and overall palatability, helping achieve balanced taste profiles that meet consumer expectations. Glycine also appears in nutritional supplement products that aim to provide additional amino acid content, aligning with consumer interest in protein-enhanced formulations. In fortified cereals and snack bars, glycine contributes to amino acid profiles while influencing taste perception. Glycine’s functional role extends to mixing with flavor blends in savory snack seasonings, where it can assist in delivering a more rounded flavor experience. These broad applications reflect formulators’ efforts to leverage glycine’s sensory and nutritional attributes to meet market demands for improved taste and nutrient content in contemporary food products.

Safety & Regulations

FDA

  • Approved: True
  • Regulation: 21 CFR 172.812

EFSA

  • Notes: EFSA specific approval status and E number not confirmed

JECFA

  • Year: 2004
  • Adi Display: No safety concern at current levels of intake

Sources

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