UK study shows benefits of high pressure processing in seafood

A UK trial research show that high pressure processing (HPP) has practical and commercial benefits in enhancing peeling and picking yields from seafood products, however the high cost of the equipment could be a limiting factor.

 

The trials were conducted by the Campden BRI and the project was jointly funded by Financial Instrument for Fisheries Guidance (FIFG), Norconserv and Seafish under a Seafish Industry Project Fund.

 

Overall high pressure processing trials were carried out on 11 species of fish including nephrops, mussels, oysters, crab, cold water prawns, warm water prawns, lobster, unsmoked salmon, squid, mackerel and cod with some positive results.

 

The main benefit from HPP treatment of mussels and oysters was the 'automatic' shucking that was achievable, along with an increase in meat weight after processing. Mussels were completely released from the shell at almost all conditions tested, with average increase in yield of 34 percent.

 

Oysters still had some loose attachment to the shell but could probably be separated by a simple vibrating belt. To prevent liquor loss it would be necessary to manually seal the product shut, in the US this is done by banding.

 

The effects of HPP on sensory quality appear to be favourable with samples generally perceived to be plump, attractive and less chewy than controls.

 

In the commercial scale crab trials, large yield increases were observed. Brown meat yield was 23 percent in the HPP treated sample, compared with 18 percent in the control.

 

Similarly, white meat yield was 12.9 percent compared with 8.3 percent in the control. However, excessive water uptake did affect product quality but it was felt this could be controlled. Yield on lobster claws was up to 23-percent higher and in many instances HPP treated lobster was considered to be higher sensory quality than the control.

 

Commercial scale trials on warm water prawns gave a significant yield increase of 4.7 percent compared with the untreated samples. It was observed that in pressure treated prawns a greater proportion of the prawn could be removed intact.

 

Seafish project manager Richard Watson said HPP can be used to successfully for certain species to increase yield and slow microbiological spoilage, adding that it has the potential for new product development and to simplify labour intensive shucking operations.

 

However, Watson said the drawback of the HPP equipment is the significant capital investment that is needed.

 

He explained that commercial sized equipment able to process 150kg and 1500kg of seafood per hour which currently costs around GBP0.5 and GBP1 million respectively. While processing costs are around GBP4 – GBP12 per kilo including the recovery of capital costs, with the larger machines offering a lower cost per kilogramme.

 

US$1 = GBP0.588 (Aug 6)