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High Pressure Processing Shows Potential

by the Fish Site Editor
02 December 2008, at 12:00am

UK - Trials have shown that High Pressure Processing (HPP) has significant potential for enhancing peeling and picking yields from seafood products, and could also help extend the shelf life of chilled seafood products.

Currently there is no commercial HPP manufacturing unit operating within the UK seafood sector, and yet world-wide HPP technology is well established with almost 20% of the current HPP applications from the seafood processing sector, reports Seafish. To address the knowledge gap in the UK trials were conducted by the Campden BRI, jointly funded by Seafish, FIFG and Norconserv, on what high pressure processing can achieve.

In the first phase of the project high pressure processing studies were carried out on 11 species of fish and shellfish in order to determine whether there were any potential processing benefits for the UK seafood processing industry. The seafood products tested were nephrops, mussels, oysters, crab, cold water prawns, warm water prawns, lobster, unsmoked salmon, squid, mackerel and cod.


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"The benefits of using HPP are very obvious but further work is needed at an industrial scale to refine and optimise processing conditions"
Craig Leadley, Campden BRI, leader of the research team

To provide further data at more commercially realistic processing volumes nephrops, warm water prawns, crab, salmon and cod were short listed for further work regarding peeling, picking and yield benefits.

The results are very clear. These trials show that HPP has significant potential for enhancing peeling and picking yields from seafood products assuming conditions are carefully optimised to ensure minimal quality changes whilst maximising yield, said Paul Williams, Head of Research at Seafish.

Significant yield increases were observed in warm water prawns that were peeled after HPP treatment (a 3.7% increase compared with a control) and the quality of the product was close to that of the untreated control. This is indicative of the sort of yield benefits that might be achievable for any seafood products requiring peeling.

Large yield increases were observed in the picking of brown crab, with an increase in brown meat yield from 18% in the control to 23% in the HPP treated sample. Similarly white meat yield increased from 8.3% to 12.9%, but in this instance the quality was poor which highlights the need for more development work to optimise the time, pressure and temperature conditions to ensure optimum meat extraction with minimum effects on product quality. Only modest yield increases were observed in Nephrops norvegicus (0.9%) but further process optimisation could improve this.

The trials on salmon and cod focused on pasteurisation and shelf-life evaluation. HPP was very successful in inactivating spoilage organisms in salmon and cod and controlling microbial loading on chilled seafood products. Opportunities were identified for it to be used as a post-pack safety treatment for ready to-eat-seafood, in much the same way as it is used as a post-pack Listeria monocytogenes inactivation step in cooked meats.

The benefits of using HPP are very obvious but further work is needed at an industrial scale to refine and optimise processing conditions for each individual species, said Craig Leadley, Campden BRI, who led the research team.

Currently seafood processors only have access to one large scale system in the UK where trials can be carried out on a contract basis. We are looking into the possibility of a pay-per-use HPP facility where small seafood processors could access equipment for commercial runs, without having to carry the risks associated with a large capital expenditure. We are hoping to organise a HPP awareness day in January in the South West to gauge interest, he said.

the Fish Site Editor