Every figure on a Certificate of Analysis means something specific. This glossary defines the technical terms a procurement or QA team meets when qualifying a marine-oil supplier, written to be read on its own, without the marketing.
TOTOX (total oxidation value)
TOTOX is a single number summarising how oxidised a marine oil is, calculated as twice the peroxide value plus the anisidine value.
TOTOX (total oxidation value) combines primary and secondary oxidation into one figure: TOTOX = 2 × PV + AV. Peroxides form first and then decompose into aldehydes, so neither measurement alone captures the full oxidative state of an oil. Lower is better. The GOED Voluntary Monograph sets a maximum TOTOX of 26 for finished omega-3 oils. Arctic Nutra verifies TOTOX on every lot.
Related How oxidation is measured
Anisidine value (AV / p-AnV)
Anisidine value measures secondary oxidation, the aldehydes that form when peroxides break down and give oxidised oil its rancid smell and taste.
The p-anisidine value (AV) quantifies the non-volatile aldehydes produced as oxidation advances. Unlike peroxide value, which can fall once oxidation is well under way, anisidine value keeps climbing, so it records an oil's oxidation history rather than just its current state. The GOED Voluntary Monograph caps AV at 20 for omega-3 oils. It is measured by reaction with p-anisidine reagent and reported as absorbance.
Related Why oxidation matters
Peroxide value (PV)
Peroxide value measures primary oxidation, the hydroperoxides that form first when a marine oil begins to degrade. Reported in milliequivalents of oxygen per kilogram.
Peroxide value (PV) captures the earliest stage of lipid oxidation. Hydroperoxides are unstable; as oxidation progresses they decompose into aldehydes, so PV can plateau or fall even as the oil degrades further. That is why it is read alongside anisidine value and combined into TOTOX. The GOED Voluntary Monograph caps PV at 5 meq O₂/kg.
Related Why oxidation matters
Free fatty acids (FFA)
Free fatty acids are fatty acids released from triglycerides by hydrolysis. A low FFA percentage indicates a fresh, well-handled oil.
Free fatty acids (FFA) form when triglycerides break down through hydrolysis, driven by enzymes, heat, or moisture during catching, storage, and processing. FFA is reported as a percentage by weight, sometimes expressed as acid value. A high level signals poor raw-material freshness or handling. Refining removes most free fatty acids; the residual figure is a quality marker reported on the Certificate of Analysis.
Related See the oil specifications
Cetoleic acid (omega-11)
Cetoleic acid is a long-chain monounsaturated omega-11 fatty acid (C22:1 n-11) found naturally and abundantly in Norwegian herring oil.
Cetoleic acid (22:1 n-11) is a monounsaturated fatty acid with its double bond eleven carbons from the methyl end, a different family from the omega-3 fatty acids. Norwegian herring oil is naturally high in it, typically 8-14% by weight. It is an emerging area of marine-lipid research; work published in journals including Frontiers in Nutrition and the British Journal of Nutrition has examined its metabolism. The research is early and carries no EFSA-authorised health claim.
Related The omega-11 research · Herring oil
Triglyceride form (TG)
Triglyceride (TG) form is the natural molecular structure of fish oil, with three fatty acids bound to a glycerol backbone, as found in the fish itself.
In triglyceride (TG) form, EPA and DHA sit on a glycerol backbone exactly as they occur in fish. Concentrated oils are sometimes converted to ethyl ester form for processing, then optionally re-esterified back into a re-formed triglyceride (rTG). Arctic Nutra supplies its marine oils in natural triglyceride form. The distinction is a specification detail formulators weigh when defining a finished product.
Related See the oil specifications
Ethyl ester form (EE)
Ethyl ester (EE) form is a processed structure where each fatty acid is bound to an ethanol molecule instead of glycerol, used to concentrate EPA and DHA.
Ethyl esters are produced when triglycerides are trans-esterified with ethanol, freeing individual fatty acids so they can be concentrated by distillation. EE is a common intermediate for high-concentration omega-3 and can be re-esterified back to a re-formed triglyceride (rTG). The form is a specification choice driven by target dose and product positioning, not a measure of quality.
Related See the oil specifications
Marine lipid
A marine lipid is a fat or oil from a marine source such as fish, krill, or algae, characterised by long-chain omega-3 fatty acids.
Marine lipids are the fats found in cold-water marine organisms. They differ from land-animal and plant fats in their high content of long-chain polyunsaturated fatty acids, principally EPA and DHA. The many double bonds that make these lipids biologically distinctive also make them chemically fragile and prone to oxidation, which is why measurement and refinement matter so much.
Related The science behind the oil
Lipid oxidation
Lipid oxidation is the chemical degradation of fats by oxygen, which in marine oils produces rancid odour, off-flavour, and loss of omega-3 quality.
Lipid oxidation is a chain reaction in which oxygen attacks the double bonds of unsaturated fatty acids. It proceeds in stages: primary products (hydroperoxides, measured by peroxide value) and secondary products (aldehydes, measured by anisidine value). Heat, light, oxygen exposure, and trace metals accelerate it. Controlling oxidation is the central technical problem in marine-oil refinement and storage.
Related Why oxidation matters
Refinement / refining
Refining is the multi-step process that removes impurities, contaminants, and oxidation products from crude marine oil to produce a clean, stable finished oil.
Marine-oil refining combines several stages, which may include degumming, neutralisation, bleaching, winterisation, molecular distillation, and deodorisation. Each removes a different class of impurity, from free fatty acids and heavy metals to colour and odour compounds. Arctic Nutra calibrates the refinement parameters, temperature, vacuum, residence time, oxygen exposure, and antioxidant protection, individually per oil rather than applying one process to all seven.
Related Our refinement approach
Molecular distillation
Molecular distillation is a low-pressure, short-residence purification step that separates compounds by molecular weight to remove contaminants and concentrate omega-3.
Molecular (short-path) distillation runs under high vacuum so compounds evaporate at lower temperatures and spend minimal time exposed to heat. It is used to strip environmental contaminants such as PCBs and dioxins and to concentrate EPA and DHA. The low pressure and short residence time limit thermal damage to the fragile omega-3 molecules.
Related Our refinement approach
Deodorisation
Deodorisation is a high-temperature vacuum step that strips the volatile compounds responsible for fishy odour and taste from refined marine oil.
Deodorisation removes the volatile aldehydes and ketones that carry fishy smell and flavour, using steam under vacuum. It requires heat, typically 180-220 °C, so it is not a cold process, and marine oil should never be described as cold-refined. The step is run with controlled time and temperature to reach a neutral sensory profile while limiting the formation of new oxidation products.
Related Our refinement approach
Winterisation
Winterisation is a controlled chilling step that removes saturated fats and waxes which would otherwise cloud or solidify the oil at low temperatures.
Winterisation cools the oil so that higher-melting-point saturated triglycerides and waxes crystallise and can be filtered out. The result stays clear and pourable when refrigerated, which matters for both appearance and downstream encapsulation. The name comes from the original practice of letting oils settle through the cold of winter.
Related Our refinement approach
COA (Certificate of Analysis)
A Certificate of Analysis (COA) is a lot-specific document reporting an oil's measured specifications, confirming it meets agreed quality limits before shipment.
A Certificate of Analysis (COA) records the tested values for a specific production lot: fatty-acid profile (EPA, DHA), oxidation markers (peroxide, anisidine, TOTOX), free fatty acids, heavy metals, and microbiological results. It ties measured quality to a traceable lot number and date. Arctic Nutra issues a COA, independently verified, with every shipment.
Related See the oil specifications
Steel drum
A steel drum is Arctic Nutra's 200-litre bulk format, holding roughly 190 kg of marine oil.
The 200 L steel drum (approximately 190 kg of oil) is Arctic Nutra's standard bulk format for liquid oil. Drums suit pilot runs, production batches, and trial orders alike, and are filled under conditions that limit oxygen exposure.
Related Delivery formats
EPA (eicosapentaenoic acid)
EPA (eicosapentaenoic acid) is a long-chain omega-3 fatty acid (C20:5 n-3) and one of the two principal omega-3s in marine fish oil.
Eicosapentaenoic acid (EPA) is a 20-carbon omega-3 with five double bonds. Together with DHA it makes up the omega-3 content most marine-oil specifications report. EFSA has authorised health claims for combined EPA and DHA intake under Regulation (EC) No 1924/2006; those claims belong to the finished-product brand, not to a bulk-ingredient supplier.
Related What the research shows
DHA (docosahexaenoic acid)
DHA (docosahexaenoic acid) is a long-chain omega-3 fatty acid (C22:6 n-3), the most structurally complex marine omega-3 and the dominant one in algae oil.
Docosahexaenoic acid (DHA) is a 22-carbon omega-3 with six double bonds. It predominates in some marine sources, notably algae and tuna oils. EFSA has authorised specific claims for DHA under Regulation (EC) No 1924/2006. As a bulk supplier, Arctic Nutra reports DHA content on the COA; health claims on finished products are the brand owner's regulatory responsibility.
Related What the research shows
Omega-3 fatty acids
Omega-3 fatty acids are polyunsaturated fats with their first double bond at the third carbon; in marine oils the key members are EPA and DHA.
Omega-3 refers to the position of the first carbon-carbon double bond, three carbons from the methyl end. The marine long-chain omega-3s, EPA and DHA, are the basis of fish-oil specifications. Their multiple double bonds make them both nutritionally notable and oxidation-prone, which is why marine omega-3 oils are measured and refined with care.
Related See the oils · What the research shows
Omega-11 fatty acids
Omega-11 fatty acids have their first double bond at the eleventh carbon; the main marine example is cetoleic acid, abundant in Norwegian herring oil.
Omega-11 denotes a double-bond position eleven carbons from the methyl end, a different family from omega-3. The principal omega-11 in marine oil is cetoleic acid (22:1 n-11); it is not a type of omega-3. Norwegian herring oil's naturally high cetoleic acid content is the basis of an emerging research story and a point of differentiation for supplement brands.
Related The omega-11 research · Herring oil
