Conventional Fish Oils

Every fat in commerce has been restructured somewhere along the line, except this one. Interesterified spreads, fractionated palm olein, re-esterified cocoa butter equivalents — all of them are engineered triglyceride architectures. A conventional fish oil is the oil the fish actually stored: a natural triglyceride in which EPA and DHA sit where nature put them, on the sn-2 and sn-1(3) positions of the glycerol backbone. That untouched arrangement caps the omega-3 content near 30% — you cannot concentrate what you refuse to rebuild — but it also hands the buyer something concentrated products cannot: a fatty acid distribution shaped by wild pelagic fish, a full complement of minor lipids, and a price per kilogram of omega-3 that concentrates struggle to match.

We supply conventional fish oils across the whole refining ladder: crude pressed oil for further processing, semi-refined lots for feed and fermentation work, fully refined natural triglyceride oil standardised to the classic 18/12 profile (EPA ≥18%, DHA ≥12%) and to species-specific lots from anchovy, sardine, capelin and menhaden. Each grade ships with peroxide value, anisidine value, free fatty acids and a full fatty acid profile on its certificate — and a winterized option that stays glass-clear at 0 °C for three hours.

What "Conventional" Actually Constrains

The word does real work on a specification sheet. Conventional means the oil left the fish as triglyceride and arrives as triglyceride: no ethyl ester conversion, no urea fractionation, no short-path distillation bumping EPA and DHA upward. Consequences follow in both directions. On the limit side, total omega-3 tops out around 28–35% of fatty acids depending on species, so buyers needing 50% or 70% payloads are on a different page of the catalogue. On the advantage side, the minor fraction survives: cholesterol stays below 0.5% but present, squalene and wax esters largely removed by refining yet the native carotenoid traces and the full sn-position distribution of the original oil remain intact — details that matter in digestion modelling, aquafeed palatability work and any study where the lipid matrix itself is the variable.

It also means the oil carries the fish's own antioxidant load at trace level rather than a dosed antioxidant system, so handling discipline — the subject of section 04 — does more to protect it than any single additive.

The Species Ledger

Conventional fish oil is a species business before it is a chemistry business. The same refinery running Chilean sardine one month and Gulf menhaden the next produces oils that differ by a third in their EPA:DHA balance. Published profiles make the spread concrete:

Two practical readings fall out of that table. First, DHA-heavy oil points toward sardine-sourced lots; EPA-leaning work is better served by menhaden or Pacific sardine. Second, because the numbers are season- and stock-dependent, we quote the actual GC-verified fatty acid profile of the specific lot rather than a species average — the certificate, not the brochure, is the specification.

Five Steps Between Press Water and Product

Conventional does not mean crude. Between the screw press and the drum sit five operations, each defined by what it removes and what it risks removing:

Winterization — controlled chilling to 0 to –6 °C so that higher-melting saturated glycerides crystallise and filter out — sits after the ladder as an option. It trades a few points of saturated fat for an oil that passes the cold test and pours cleanly from cold storage, and it nudges the liquid fraction's EPA and DHA share upward without ever calling the oil concentrated.

The Oxidation Ledger

Fish oil has more double bonds per molecule than almost any fat in commerce, and every one of them is a place where a radical can start. The protection plan is therefore mechanical before it is chemical: nitrogen or argon blanketing from the first centrifuge to the sealed drum headspace, chilled storage, no light, and chelators — citric acid or EDTA — to tie up the iron and copper that stainless contact inevitably sheds. Mixed tocopherols at 100–500 ppm are dosed where the customer's application allows; published work on mackerel oil showed 50 ppm α-tocopherol already effective over a 66-day storage trial at 4 °C and below.

Freshness is then read from three numbers that tell one story in two acts. Peroxide value tracks the primary hydroperoxides — the transient first act, which peaks and decays. Anisidine value captures the secondary aldehydes and ketones — the residue that never decays away. TOTOX, defined as 2×PV + AV, folds both acts into one figure; the industry treats 26 as the ceiling a finished oil must never cross, and well-handled refined oil lands far under it (typical certificates show PV 0.5–3 meq/kg with AV 5–15). Kinetics make the case for discipline: oxidation rate roughly doubles per 10 °C, and open-vial studies show ethyl ester oils — not our product, but the comparison is instructive — oxidising measurably faster than natural triglycerides at identical EPA and DHA levels.

Reading a Certificate, Line by Line

A refined 18/12 natural triglyceride certificate, and what each line is really telling you:

How Every Lot Is Verified

Fatty acid identity and grade are confirmed by capillary gas chromatography of the fatty acid methyl esters — the FID trace is the product's fingerprint, and no grade ships until its own profile has been run. Peroxide value comes from the classical iodometric titration, anisidine value from spectrophotometry of the aldehyde–anisidine adducts, and oxidative stability projections from accelerated testing in which warmed oil is sparged with air until conductivity of the effluent breaks — the induction period that predicts drum-life behaviour. Contaminant lines are ICP-based for metals and GC-based for the persistent organic panels.

07 / Where Conventional Oil Earns Its Place

Buyers reach for the natural triglyceride grade for reasons that have nothing to do with nostalgia:

• Feed formulations. Aquaculture feeds — the reference lipid for salmonid and marine larval diets, where palatability, energy density and the EPA:DHA balance of the source oil all carry directly into growth trials.
• Animal nutrition. Pet food and specialty feed premixes, where the oil's native minor fraction and natural triglyceride structure support coating and palatant systems.
• Research work. Lipid metabolism and digestion studies, emulsion science and oxidation chemistry — anywhere the natural sn-position distribution and minor fraction are part of the experimental design rather than a nuisance.
• Industrial uses. Industrial oleochemistry — leather fatliquoring, lubricant and additive research, and renewable polyol feedstock where the iodine value does the work.

Choosing a Point on the Ladder

Custom Manufacturing and Grades

Beyond the standing grades, we build oil to the parameters the project actually needs: species and origin selection against a target EPA:DHA ratio, acid-value ceilings below the standard release, winterization depth tuned to a stated cold-test temperature, antioxidant systems specified by name and dose, and packing from 25 kg pails to 190 kg nitrogen-flushed drums and IBCs. If the certificate line you care about is not on this page, it is still probably a conversation rather than a compromise — send the specification and the lot we quote will carry exactly those numbers.

For Research or Industrial Raw Materials, Not For Personal Medical Use!