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The application of power ultrasound sped up the drying kinetics at every temperature tested, achieving drying time reductions of up to 77%, which was linked to the improvement in diffusion and convective mass transport. In overall terms, ultrasound application involved a greater degradation of polyphenol and flavonoid contents and a reduction of the antioxidant capacity, which was related to the cell disruption caused by the mechanical stress of acoustic waves. 43

The use of slurry ice, both alone and in combination with ozone, as compared with traditional flake ice was investigated as a new refrigeration system for the storage of sardine (Sardina pilchardus). Microbiological, chemical and sensory analyses were carried out throughout a storage period of 22 days. According to sensory analyses, sardine specimens stored in ozonised slurry ice had a shelf life of 19 days, while counterpart batches stored in slurry ice or flake ice had shelf lives of 15 and 8 days, respectively. Storage in ozonised slurry ice led to significantly lower counts of aerobic mesophiles, psychrotrophic bacteria, anaerobes, coliforms, and both lipolytic and proteolytic microorganisms in sardine muscle, and of surface counts of mesophiles and psychrotrophic bacteria in sardine skin as compared with the slurry ice and the flake ice batches. In all cases, the slurry ice batch also exhibited significantly lower microbial counts, both in muscle and skin, than the flake ice batch. Chemical parameters revealed that the use of slurry ice slowed down the formation of TVB-N and TMA-N to a significant extent in comparison with storage in flake ice, the evolution of TMA-N being the most adequate parameter to detect quality losses. A combination of slurry ice with ozone also allowed a better control of pH and TMA-N formation as compared with slurry ice alone. Proteus vulgaris and Staphylococcus sciuri were identified as the main spoilers of sardine muscle. This work demonstrates that the combined use of slurry ice and ozone for the storage of sardine is can be recommended to improve the quality and extend the shelf life of this fish species.

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consequence of storage in slurry ice. A slower production of both trimethylamine and total volatile bases was also observed. Likewise, low levels of total aerobes, anaerobes, coliforms, and proteolytic bacteria were attained. According to the biochemical, microbial and sensory analyses, and the statistically-significant (p<0.05) differences observed with respect to data obtained in parallel with conventional icing, the application of slurry ice to farmed turbot is advisable to achieve better quality maintenance during storage and distribution.

The use of ozonised slurry ice was investigated as a new refrigeration system for the storage of farmed turbot (Psetta maxima), a non-fat fish species of high commercial value. With this purpose in mind, an ozone generator device was coupled to a slurry ice system working subzero at-1.5ºC. The ozone concentration was adjusted to a 700 mV of redox potential, and the slurry ice biphasic mixture was prepared at a 40% ice/60% water ratio and a 3.3% of salinity. Microbiological, chemical and sensory analyses were carried out throughout a storage period of 35 days. Although certain biochemical parameters indicative of fish freshness-such as the rate of nucleotide degradation or TMA-N formation-were not significantly affected by the presence of ozone in the slurry ice mixture, storage in ozonised slurry ice significantly slowed down of mechanisms responsible for lipid hydrolysis-as determined by the release of free fatty acids-and lipid oxidation-evaluated by the peroxide value, the thiobarbituric acidindex and by the rate of browning reactions determined at 450/400 nm-in farmed turbot. Storage in ozonised slurry ice also led to significant (p<0.05) lower counts of both total aerobes and psychrotrophic bacteria in both turbot muscle and skin, as compared with the control batch stored without ozone. Sensory analyses confirmed an extended shelf life of turbot specimens stored in ozonised slurry ice, these maintaining "A" sensory quality up to day 14, while counterpart batch stored in slurry ice kept this quality only up to day 7. The combination of ozone and slurry ice may be recommended for the chilling and storage of farmed turbot with a view to extend its shelf-life.