ETHOXYQUIN

CAS: 91-53-2 ANTIOXIDANT

ETHOXYQUIN (CAS 91-53-2) is a synthetic antioxidant widely used to protect fats and sensitive ingredients from oxidation and color loss in foods such as spices and animal feeds.

What It Is

ETHOXYQUIN is a synthetic chemical belonging to the quinoline family that functions primarily as an antioxidant. It is a viscous compound with the chemical designation 1,2-dihydro-6-ethoxy-2,2,4-trimethylquinoline and carries the CAS number 91-53-2. It is known under several synonyms related to its structure and function, including NSC-6795, reflecting its chemical registry identity. As an antioxidant, ETHOXYQUIN interrupts and slows oxidative reactions by scavenging free radicals and protecting lipids in complex mixtures. Antioxidants such as ETHOXYQUIN are important in food technology because they help preserve the stability and sensory qualities of ingredients that are susceptible to oxygen-induced changes. This includes maintaining color integrity in spice preparations and protecting fats from becoming rancid during storage and processing. In regulatory contexts, ETHOXYQUIN’s use is defined based on specific allowable applications and conditions, such as in certain spice products permitted under the U.S. Code of Federal Regulations (CFR) for direct addition to human foods and in approved animal feeds under defined conditions. The inclusion of ETHOXYQUIN in regulatory inventories reflects these defined functions and uses.

How It Is Made

ETHOXYQUIN is produced through organic chemical synthesis that builds the quinoline backbone with an ethoxy substituent and methyl groups at defined positions. General production involves the condensation of a substituted aromatic amine with appropriate carbonyl precursors under controlled catalytic conditions to form the core quinoline structure. This synthetic route results in a mixture that is subsequently purified to achieve the target antioxidant compound at high purity levels. Commercial manufacturing of ETHOXYQUIN typically involves standard organic synthesis techniques used for specialty chemicals, including distillation and recrystallization steps to ensure product consistency and compliance with specified quality standards. While specific proprietary steps may vary by manufacturer, the foundational chemistry relies on well-established reactions for quinoline derivatives. In industrial settings, manufacturers produce ETHOXYQUIN in liquid or powdered form for blending into food and feed formulations. The manufacturing process takes into account storage stability and minimal degradation of the antioxidant, with measures in place to control exposure to oxygen, light, and heat which can affect product quality.

Why It Is Used In Food

ETHOXYQUIN is used in foods because oxidation is a major cause of quality deterioration in many products. Fats and oils, vitamins, and pigments are prone to oxidative degradation, which can lead to off-odors, rancidity, loss of nutritional value, and color changes. By inhibiting oxidative chain reactions, antioxidants like ETHOXYQUIN help maintain product quality over time. In spice preparations such as chili powder and paprika, ETHOXYQUIN protects natural carotenoid pigments from oxidation, preserving vibrant color that consumers expect. Oxidation of these pigments not only dulls color but can also impact flavor indirectly by forming off-notes. In animal feeds, the compound helps protect fat-soluble vitamins and oils from oxidative breakdown during storage and transport. Fats in feeds are especially prone to oxidation, and antioxidants contribute to maintaining feed nutritive value. The inclusion of ETHOXYQUIN in certain authorized products reflects this purpose, helping formulators achieve stability in complex blends.

Adi Example Calculation

An illustrative example helps explain how an acceptable daily intake (ADI) would be used if defined: If a regulatory body were to set an ADI of X mg per kilogram of body weight per day for a compound, then a 70 kilogram adult would have an overall daily intake limit of 70 times X mg per day. For instance, if X were 0.1 mg/kg, the daily intake limit for that 70 kg adult would be 7 mg per day. This example is for explanatory understanding only and does not reference a verified ADI value for ETHOXYQUIN.

Safety And Health Research

Safety evaluations of ETHOXYQUIN have been conducted by regulatory scientific panels, considering its overall toxicological profile, potential impurities, and metabolic products. For example, assessments have examined its antioxidant function and metabolites formed during oxidation, noting that certain oxidation products and manufacturing impurities may present safety uncertainties. Regulatory reviews consider data from in vitro and in vivo studies on genotoxicity, chronic exposure, and other endpoints to understand potential risks. In evaluating ETHOXYQUIN, authorities have also examined impurities such as p-phenetidine, which may be present at low levels and have differing hazard profiles. These considerations influence decisions on allowable uses and conditions of safe application. Importantly, decisions to suspend or restrict use in some regions reflect precautionary responses to data gaps identified in toxicology and exposure assessments. This underscores the role of evidence-based risk assessment in regulatory decision-making for food additives.

Regulatory Status Worldwide

In the United States, ETHOXYQUIN is explicitly authorized for use in certain food products under the U.S. Code of Federal Regulations. Specifically, 21 CFR 172.140 permits ETHOXYQUIN as an antioxidant for preservation of color in chili powder, paprika, and ground chili at defined maximum levels. This regulatory citation reflects an established condition of safe use in those products. Additionally, it appears in CFR Part 573.380 for safe use in animal feeds under prescribed conditions, recognizing its acceptance for that technical function in animal nutrition. In contrast, regulatory authorities in the European Union reviewed ETHOXYQUIN as a feed additive and, due to data gaps and safety considerations, the authorization was suspended under Regulation (EU) No 2017/962, with transitional provisions that have expired, effectively discontinuing its permitted use as a feed additive across EU member states. (European Food Safety Authority) Worldwide, specific regulatory status can vary by jurisdiction, with some countries continuing to permit ETHOXYQUIN under defined conditions and others restricting or disallowing its use based on local safety assessments. Where authorized, clear labeling and adherence to maximum use levels form part of the compliance framework.

Taste And Functional Properties

ETHOXYQUIN itself has minimal direct sensory impact in properly formulated products. Its role is functional rather than sensory, working at low concentrations to slow oxidation and preserve sensory attributes of other ingredients. In spices, it helps maintain the visually appealing color of red and orange carotenoids without imparting off-flavors when used within regulated limits. From a functional standpoint, ETHOXYQUIN is relatively insoluble in water but blends effectively in lipid-rich systems where oxidative reactions are most problematic. Its antioxidant activity stems from the chemical structure’s ability to donate electrons to reactive species, stabilizing them and preventing chain reactions that lead to rancidity. ETHOXYQUIN’s performance can vary with formulation, temperature, and presence of other ingredients, but its use is selected specifically to protect sensitive constituents without altering taste profiles at permitted levels. Because it is used at low concentrations and in specific applications, sensory thresholds for ETHOXYQUIN itself are generally not a primary concern in product formulation, with focus instead on its stabilizing function.

Acceptable Daily Intake Explained

Acceptable Daily Intake (ADI) is a regulatory concept that represents the amount of a substance that can be consumed every day over a lifetime without appreciable health risk, based on available scientific data. ADIs are typically derived by identifying a no-observed-adverse-effect level (NOAEL) from toxicological studies and applying safety factors to account for uncertainties in data and differences between test animals and humans. For some additives, international expert committees such as JECFA provide ADI values after thorough evaluation. In the case of ETHOXYQUIN, specific ADI values for human dietary exposure have not been clearly established in widely accessible JECFA databases, and authoritative numeric figures could not be confirmed for direct inclusion here. As a result, ADI-related numeric fields are set to null due to the absence of explicitly d evidence from authoritative sources. This does not imply safety concerns per se, but reflects the evidence requirement for regulatory documentation.

Comparison With Similar Additives

ETHOXYQUIN belongs to a class of synthetic antioxidants used to protect foods from oxidation, alongside other compounds such as butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA). Like ETHOXYQUIN, these antioxidants are selected for their ability to protect lipids and sensitive ingredients. BHA and BHT are widely permitted in many regions and have established ADI values, whereas ETHOXYQUIN’s regulatory acceptance varies by jurisdiction based on risk assessments and data availability. Another antioxidant, tocopherol (vitamin E), functions as a natural antioxidant in foods with generally broad acceptance and labeling as a natural nutrient. The choice of antioxidant depends on product matrix, regulatory allowances, and desired shelf-life outcomes. Compared to natural antioxidants, synthetic options like ETHOXYQUIN and BHT often offer stronger performance in certain lipid-rich systems but require explicit regulatory clearances for specific applications.

Common Food Applications Narrative

ETHOXYQUIN finds application where protection against oxidative deterioration is needed. One of its most recognized uses is in spice products like chili powder and paprika, where it preserves color and quality during storage and distribution. Oxidative reactions can dull the natural pigments in these spices, leading to color loss that can affect visual appeal and consumer perception. By acting as an antioxidant, ETHOXYQUIN helps maintain vibrant hues that are desirable in finished products. Another key application for ETHOXYQUIN is in animal feed formulations. Feeds containing oils, fats, and fat-soluble vitamins are particularly susceptible to lipid oxidation during manufacturing and storage. The presence of antioxidants helps protect nutrient integrity and reduces the formation of off-odors or breakdown products that could compromise feed quality. This practical use in animal nutrition highlights how antioxidants contribute to preserving the value of feed ingredients. Beyond human foods and animal feeds, antioxidants similar to ETHOXYQUIN are occasionally evaluated for roles in other processed products where oxidation can influence appearance or integrity. The selection of ETHOXYQUIN over other antioxidants depends on regulatory allowances, product matrix considerations, and desired shelf-life outcomes.

Safety & Regulations

FDA

  • Approved: True
  • Regulation: 21 CFR 172.140

EFSA

  • Notes: Use suspended in EU feed additives due to safety assessment outcomes

JECFA

  • Notes: No explicit JECFA ADI citation could be confirmed

Sources

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