The MUSTEC project for the development of multi-sensor techniques for monitoring the quality of fish attempted to find out how sensory instruments that mimic human senses to take rapid measurements of freshness could be created.
The team claimed that the instrumental measurements they developed could be calibrated to be as good as those of a trained sensory panel.
"Freshness is the most important attribute of the quality of fish," said Dr Paul Nesvadba, head of food physics at the Robert Gordon University in Aberdeen who co-ordinated the project. "Freshness is a complex concept, but can be estimated by a combination of several sensory attributes such as appearance, smell, texture and of course taste.
"Until now, the most accurate way we have had to monitor the freshness of fish was a trained sensory panel made up of 10 people who have to be specially trained. This can be expensive as the training is critical and all members of the panel are not always accessible."
In order to develop the sensory instruments, the research team had to develop a quality index that characterises the freshness of the fish by combining the measurements taken by the sensors. The team used instruments to take readings in four main areas and these readings were then combined to give an overall measurement of the freshness of the fish.
The four areas were, firstly, texture, where instruments compress the body of the fish to measure its firmness and elasticity. This varies over a number of days in chilled storage and over several months in frozen storage.
The texture measurements are particularly sensitive to changes during the first four days of chilled storage, thereby complementing the electronic noses that are sensitive from day three onwards.
The second area was the measurement of volatile compounds. These were assessed using 'electronic' noses based on conductance changes in polymer layers and adsorption on metal porphyrrins to monitor odour, strongly associated with fish freshness.
The third area was electrical impedance, using commercial instruments already available to measure the disruption of fish muscle by autolytic spoilage, while the final area of measurement was the assessment of optical indicators such as colour and image analyses.
The team believes that the results of the project are of great value as a basis for designing objective multi-sensor instruments for evaluating fish freshness.
Partners from seven different countries - the United Kingdom, Iceland, Norway, Spain, Germany, Italy and Denmark - carried out the MUSTEC project. The initiative received a grant of €730,000 from the Information Society Technology (IST) Programme of the European Union's Framework Programme towards the overall cost of just over €1 million.
"Over seventy per cent of the funding for this project came from the EU's Fifth Framework programme, so it seems fair to assume that, without it this project may well not have gone ahead," said Peter Walters, UK National Contact Point for IST within the EU's 6th Framework Programme.
"Yet the results of the project will benefit all of us who eat fish as well as the thousands of people who work in the fish processing industry."
The EU's Framework Programmes are the world's largest, publicly funded, research and technological development programmes. The Sixth Framework Programme (FP6) covers the period 2002-2006 and is the European Union's main instrument for the funding of collaborative research and innovation. It is open to public and private entities of all sizes in the EU and a number of non-EU countries. It has an overall budget of €19 billion.