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from various fish raw material sources as a supplement in easy shucking of seafood, particularly oysters and abalone.
aquafeeds. Pressure at 250 to 350 MPa breaks the muscle that holds
the animals to their shells. When the oysters or abalone
are unpacked, the meat simply slides out of the shell –
no knives required.

A preliminary trial provided reasonable extraction of intact
portions of raw meat from the claws of Champagne Crab.
This could improve the meat recovery and marketability of
the species, which can be difficult to handle because of its
small spines and hairs.
Credit: Kerri Choo

Mussel stock produced following enzymatic hydrolysis of second grade Higher pressures of up to 650 MPa effectively kill most
mussels.
organisms present in the meat, and this process was able to
The enzyme hydrolysis process may also allow specific extend the shelf life of cooked crabmeat and cooked finfish
chemical components to be extracted for further testing of from five days to up to three weeks. As a result a pilot, chilled,
functional properties. This has been the case for cold-tolerant packaged, cooked crabmeat product with an extended shelf
enzymes extracted from hydrolysed Patagonian Toothfish life was developed using this process, performing well in state
heads, provided by Austral Fisheries. Of interest to note is food awards.
that a multinational detergent manufacturer (unsuccessfully)
investigated the functionality of the extracted enzymes for However, the trials did show that high-pressure processing
use in cold-water washing detergents. As well, extracts of may affect texture, colour and other sensory properties, so
toothfish and sardine waste subjected to enzyme hydrolysis, individual and detailed product development is needed to
Credit: SAMPI
have been tested for food functionality parameters such optimise opportunities from this technology.
as anti-oxidant activity, water and oil holding capacity, Protein separation
emulsifying ability and foaming ability.
Fillet recovery rates for finfish vary from 30 to 50 percent.
Drying techniques Over 20 percent protein can be recovered through mechanical
meat separation technologies applied to filleted fish frames
The swim bladders of some fish are normally removed and and other seafood ‘waste’.
may be discarded when fish are gutted. However there is a
growing Chinese demand for dried swim bladders for use
in traditional medicine; a similar product is already being
supplied from Iceland.
Machine-dried air bladders from various finfish species have
been tested against traditional Asian sun-dried products.
Enzymes are also being trialled to ‘clean up’ the bladders
before drying, rather than requiring fishers to remove the
blood and membrane as the fish are harvested.
Pasteurisation

High-pressure processing (HPP) operates at temperatures of
15°C to 20°C, using pressure at increasing levels to achieve
different end results. For the seafood sector, three different Credit: Janet Howieson
applications have been identified: the easy shucking of Snapper fillet frame and possible outputs.
shellfish, meat extraction and extended shelf life.
Trials used a drum separator with sieves ranging from two
In trials with a commercial HPP operator in Western to 10 millimetres to produce mince of varying grades and
Credit : Dexter Yard
Australia, packaged seafood – both raw and cooked – was ‘chunkiness’ from a variety of finfish, which could then be
processed under high pressures in cycles of two to 10 used to create new products such as fish cakes or croquettes,
minutes. High pressure proved to be a viable option for the or potentially for use in high-temperature extruded products.

INFOFISH International 3/2020 ● www.infofish.org