How Is Imitation Crab Made? Inside a Surimi Production Line

How is imitation crab made? White fish is minced and washed repeatedly in cold water until only the gel-forming protein remains; that protein is stabilised, frozen, then later blended with starch, egg white, salt and flavouring, formed into a thin sheet, heat-set, coloured on one surface, rolled into a stick and cut. The whole sequence exists to build one property: elasticity. Everything else is downstream of it.

We have run surimi lines in Samut Sakhon, Thailand since 1994 — more than 30 years, over 4,000 tonnes a year — so what follows is the process as it actually runs, including the steps that decide whether the finished stick snaps or crumbles.

Step 1 — Why is the fish washed so many times?

Short answer: washing removes fat, blood, enzymes and water-soluble proteins, leaving a concentrated, neutral-tasting protein that can form a gel. Skip it and you have minced fish, not surimi.

This is the step that turns a fish into an ingredient. Repeated cold-water rinsing strips out everything that would make the product smell fishy, discolour, or break down in storage. What remains is myofibrillar protein — the fraction that will later set into an elastic solid.

Two practical consequences follow. Water quality and temperature control during washing directly determine the whiteness and odour of every batch downstream. And because the process removes so much material, surimi yield from raw fish is modest, which is a large part of why grade differences translate so directly into price.

Step 2 — What is a cryoprotectant and why does it matter?

Short answer: sugar and phosphate blended in before freezing. Without them, freezing destroys the protein’s ability to gel, and the surimi arrives at the next factory unusable.

Frozen surimi is traded globally as a raw material, which means it must survive months of frozen storage and transport with its functionality intact. Ice crystal formation would otherwise denature the protein permanently.

This is worth understanding if you are sourcing: the surimi that arrives at a snack factory is already a processed, graded, specified commodity. Asking a manufacturer which grade they buy tells you a great deal about the product you will receive.

Step 3 — How does the paste become elastic?

Short answer: salt is added, which dissolves the protein into a sticky sol; the paste is then held and heated so it sets into a gel. This step is where gel strength is created — or lost through poor temperature control.

Salt here is functional, not seasoning. Without it the protein will not solubilise, and without solubilising it cannot form the three-dimensional network that gives the finished product its bite. That is why genuinely low-sodium imitation crab is difficult rather than merely unpopular.

Temperature control during setting is the craft of the whole process. Too fast, and the network forms unevenly; too slow at the wrong temperature, and enzymes degrade the protein. A plant that has run the same product for years holds this window tightly, and that consistency is most of what an experienced buyer is paying for.

Stage	Input	What can go wrong
Washing	Minced fish, cold water	Warm water or too few cycles: grey colour, fishy odour
Dewatering	Washed mince	Too much moisture left: soft, watery texture
Cryoprotectant blending	Refined paste, sugar, phosphate	Omitted or under-dosed: gel loss in frozen storage
Chopping with salt	Surimi, salt, starch, egg white, oil	Overheating during chopping: protein damage before setting
Setting and cooking	Formed sheet	Wrong temperature window: weak or uneven gel
Colouring and forming	Cooked sheet	Colour bleeding through instead of staying on the surface

Step 4 — Why is the colour only on the outside?

Short answer: the colour is applied to one face of the sheet before it is rolled, so the finished stick shows a red-orange exterior and a white interior. Colour running all the way through usually means it was mixed into the paste instead.

It is a small detail that happens to be a useful quality tell. On a well-made stick the transition between the coloured surface and the white body is sharp. The pigment itself is typically paprika-based or, in some formulations, carmine — which matters for halal and vegetarian claims, so it is worth specifying by name rather than as “red colour”.

Step 5 — What happens after forming?

Short answer: the sheet is rolled or shredded into the final shape, cut, then pasteurised and packed. Frozen formats go through controlled freezing designed to protect the gel that was just built.

Different products diverge at this point rather than earlier. The same base paste can become a crab stick, a fish ball, a chikuwa tube, a fish chip, or a thin squid-style sheet, depending on forming and finishing. This is why a factory’s product range is a meaningful signal: shared upstream process, very different downstream equipment.

What does this mean if you are sourcing a surimi product?

Short answer: ask about surimi grade, gel strength and setting control, not just price per carton. Those three answers predict the product you will receive far better than a quotation does.

A useful test of a supplier is whether they can discuss the process in these terms at all. Specifications built on measurable properties — grade, gel strength, moisture, dimensions — hold across batches. Specifications built on adjectives do not.

Realistic development timelines follow from the process too. A prototype adapted from an existing line within about four weeks is a professional pace; a sample that arrives in days is usually a stock product relabelled.

Frequently asked questions

Is imitation crab cooked during manufacture?

Yes. Heat setting is intrinsic to the process, so the product is ready to eat from the pack unless the brand states otherwise.

Why do some sticks feel rubbery and others mushy?

Both are gel strength outcomes — too much elasticity from formulation or setting on one side, too little protein or too much starch and moisture on the other.

Can imitation crab be made without starch?

Not really. Starch contributes structure and water binding as well as cost reduction. Reducing it raises the fish protein requirement and the price.

Does freezing at home ruin it?

It softens it. Ice crystals disrupt the protein network, and a domestic freezer cannot replicate the controlled freezing and cryoprotectant system the industrial process relies on.

What fish species are used?

Mild, low-fat white species. Alaska pollock is the global reference; tropical species such as threadfin bream and lizardfish are common in Southeast Asian production, often blended.

---

Big Kitchen is an OEM manufacturer of fish snacks and frozen surimi products in Samut Sakhon, Thailand, producing fish strips, fish chips, squid sheets, imitation crab and frozen surimi items for brands in Korea, Japan, China and beyond, from a facility certified to FSSC 22000, HACCP, GMP and HALAL. To discuss a product specification, see our OEM service and product range, or contact the team.

Last updated: August 2026 · Written by the Big Kitchen production team

Related services & references

Learn more: OEM manufacturing service · Fish snack & surimi product range · About Big Kitchen · Contact the team

Standards referenced (official sources): FSSC 22000 · Codex Alimentarius (FAO/WHO) · Thai FDA