OCTYL GALLATE

CAS: 1034-01-1 ANTIOXIDANT

Octyl gallate is a synthetic ester of gallic acid and octanol that functions as an antioxidant in some food applications and technical products.

What It Is

Octyl gallate is a synthetic organic compound formed by the esterification of gallic acid with octanol that is primarily used for its antioxidant properties in certain food formulations and technical products. Its Chemical Abstracts Service (CAS) registry number is 1034-01-1, and it is identified in international additive registries under the INS number 311. As a member of the gallate ester family, it acts to slow oxidative degradation of fats and oils, helping to maintain product stability and quality. It has been evaluated by international scientific bodies for safety in food use and is recognized for its antioxidant function. Octyl gallate has a white to off‑white solid appearance and limited water solubility, consistent with its chemical structure and ester functional group. The compound may also be referred to by related names derived from its chemical composition and structure, including octyl gallate benzoic acid derivatives and other systematic nomenclature variants (e.g., octyl 3,4,5‑trihydroxybenzoate). These alternative names reflect the underlying gallic acid moiety and the octyl alcohol ester linkage that define this antioxidant additive.

How It Is Made

Octyl gallate is manufactured via a non‑proprietary esterification reaction in which the carboxyl group of gallic acid is chemically bonded to the hydroxyl group of 1‑octanol under controlled conditions. Industrial production of ester additives like octyl gallate typically involves an acid catalyst and an appropriate reaction environment to facilitate the formation of the ester linkage while minimizing unwanted side products. Once synthesized, the material is purified to meet relevant additive specifications for food or technical use, ensuring a consistent composition and performance profile. Quality control in production addresses factors such as residual reactants, catalyst removal, and conforming to standard chemical purity criteria. While specific industrial methods and process parameters vary between suppliers, the general approach of ester formation with subsequent purification is consistent across manufacturing practices for this class of compounds.

Why It Is Used In Food

Octyl gallate serves a technological role in food systems by acting as an antioxidant, which means it helps slow the oxidative breakdown of lipids and fats that contribute to rancidity, off‑flavors, and textural changes. When incorporated into fat‑containing foods, antioxidant additives like octyl gallate stabilize fats against oxidation initiated by exposure to oxygen, light, heat, or metal ions, thereby prolonging product shelf life and preserving sensory quality. The antioxidant function is important for formulated products that rely on the stability of unsaturated fatty acids, such as spreads or high‑fat ingredients. Octyl gallate is often used synergistically with other antioxidants to enhance overall performance and to tailor formulations for specific processing and storage conditions. Its inclusion in select food applications is dictated by regulatory standards that define allowable ingredients based on safety assessments and technical need.

Adi Example Calculation

The following illustrative explanation describes how acceptable daily intake (ADI) calculations are typically derived in regulatory science using hypothetical values. This example is for conceptual understanding only and does not represent a recommended intake for octyl gallate. Regulatory bodies start by identifying a no‑observed‑adverse‑effect level (NOAEL) from animal studies, representing a dose at which no adverse effects are seen. An uncertainty factor (often 100 or greater) is then applied to account for differences between animals and humans and variability among individuals. For example, if a hypothetical NOAEL of 50 mg per kilogram of body weight per day were identified in an animal reproductive toxicity study, dividing this value by a composite uncertainty factor of 100 would yield an illustrative ADI of 0.5 mg per kilogram of body weight per day. A person weighing 60 kilograms would then have an illustrative intake equivalent to 30 mg per day when applying this example ADI and weight. This calculation is illustrative of the ADI concept and is not intended as regulatory guidance for octyl gallate specifically.

Safety And Health Research

Scientific and regulatory evaluations of octyl gallate have focused on its antioxidant function and the available toxicological evidence that informs safety assessments. Reviews by expert panels have noted limited toxicological databases for octyl gallate, and in some assessments, data gaps have constrained definitive conclusions on chronic toxicity, carcinogenic potential, and systemic effects across all use scenarios. Toxicological research for food additive assessment typically considers endpoints such as acute and subchronic toxicity, reproductive and developmental effects, and potential genotoxicity, with expert bodies drawing on available studies to identify no‑observed‑adverse‑effect levels where possible. In the case of octyl gallate, some expert reviews have observed that limitations in the available studies made it difficult to establish specific safety thresholds with high confidence. These safety evaluations inform regulatory decisions and help define whether specific numerical intake values can be recommended or whether use should be restricted or removed from approved lists based on the assessed evidence.

Regulatory Status Worldwide

Regulatory status of octyl gallate varies internationally. In the United States, octyl gallate is listed as an optional preservative antioxidant in the Code of Federal Regulations specifically for standardized margarine, where preservatives including octyl gallate are permitted at defined maximum levels in finished products under 21 CFR 166.110. This regulatory listing reflects approval for use in this specific application within U.S. federal food standards. By contrast, regulatory authorities in the European Union have conducted comprehensive scientific reviews of octyl gallate as a food additive, including a re‑evaluation by the European Food Safety Authority (EFSA) Panel on Food Additives and Nutrient Sources added to Food. EFSA’s scientific opinion highlighted limitations in the toxicological data and identified data gaps that constrained a full safety assessment, and subsequent European Commission regulatory action resulted in the removal of octyl gallate from the Union list of approved food additives. International bodies such as the Joint FAO/WHO Expert Committee on Food Additives (JECFA) have evaluated octyl gallate and noted that a temporary acceptable daily intake was not extended in later evaluations, indicating that no specific ADI was allocated based on the available data at the time. These diverse regulatory positions underscore the evolving assessment of safety and permitted uses of octyl gallate in different jurisdictions.

Taste And Functional Properties

Octyl gallate itself contributes minimal organoleptic impact in properly formulated food products, as its primary role is functional rather than sensory. Chemically, it exhibits antioxidant activity, meaning it interacts with free radicals and oxidation pathways that otherwise degrade lipids in food matrices. Its limited solubility in water and greater compatibility with lipid phases makes it more suitable for fat‑rich environments where oxidative degradation is a concern. From a sensory perspective, octyl gallate is generally considered neutral at typical use levels, with any intrinsic odor or taste effectively masked in finished products. Functionally, it is stable under typical processing and storage conditions encountered in foods that include fats and oils, although like all additives, its performance can be influenced by formulation variables such as pH, temperature, and the presence of pro‑oxidants.

Acceptable Daily Intake Explained

An Acceptable Daily Intake (ADI) is a regulatory‑derived estimate of the amount of a substance that can be consumed daily over a lifetime without appreciable health risk, based on available toxicological data and application of safety factors. For some food additives, expert committees such as JECFA establish an ADI when sufficient data exist to identify a no‑observed‑adverse‑effect level and apply uncertainty factors to account for variability in human responses. In the case of octyl gallate, historical evaluations by international expert groups have concluded that the available data were not sufficient to allocate a specific ADI with confidence, and as a result no formal ADI value was assigned in those evaluations. This means that regulators may review broader safety evidence and exercise caution in approving or setting limits for use in foods when the data do not support a clear intake threshold. Consumers and industry stakeholders should understand that an ADI is a risk assessment tool used by regulators rather than a recommended level of daily intake.

Comparison With Similar Additives

Octyl gallate belongs to a class of esterified gallic acid antioxidants that includes other food antioxidants such as propyl gallate and dodecyl gallate. These compounds share a similar basic mechanism—protecting fats and oils from oxidative degradation—but differ in alkyl chain length and regulatory acceptance in various markets. Propyl gallate, for example, has been evaluated more extensively and historically enjoyed broader regulatory approval in certain regions, with some bodies establishing intake values when data support such determinations. Dodecyl gallate, like octyl gallate, may face similar data limitations in safety evaluations. When food formulators compare such antioxidants, they consider not only their functional efficacy in protecting lipids but also their regulatory status, permitted use levels, and compatibility with other components. The choice of antioxidant in a given product reflects a balance of functional performance, regulatory compliance, and formulation goals.

Common Food Applications Narrative

In food applications, octyl gallate has historically been used as an antioxidant in products that contain significant amounts of unsaturated fats or oils. This includes applications such as margarine and other fat‑based formulations where oxidative stability is desired. The antioxidant function of octyl gallate helps protect against the development of off‑flavors and extends shelf life by slowing lipid oxidation processes. In consumer contexts, formulations incorporating antioxidants like octyl gallate may include fat‑rich foods that are subject to oxidation during processing, distribution, or storage. While its use is more limited compared to some other antioxidants, the incorporation of octyl gallate in select products reflects its role in maintaining quality in lipid‑containing products. Manufacturers typically select antioxidant systems based on the particular stability challenges of their products and regulatory allowances in their markets.

Safety & Regulations

FDA

  • Approved: True
  • Regulation: 21 CFR 166.110

EFSA

  • Notes: EFSA evaluation noted insufficient data to support a definitive ADI and regulatory removal from approved list
  • E Number: E311

JECFA

  • Year: 1996
  • Notes: JECFA did not allocate an ADI during its evaluation due to limited data
  • Ins Number: 311

Sources

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