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After a 1.5 year screening survey in the lagoons of Western Greece in order to isolate and culture sturdy species of microalgae for aquaculture or other value added uses, as dictated primarily by a satisfactory potential for their mass-culture, five species emerged and their growth was monitored in laboratory conditions. Amphidinium carterae, Nephroselmis sp., Tetraselmis sp. (var. red pappas), Asteromonas gracilis and Dunaliella sp. were batch cultured using low (20 ppt), sea (40 ppt) and high salinity (50 or 60 or 100 ppt) and in combination with a low (2000 lux) and high (8000 lux) intensity of illumination. The results exhibited that all these species can be grown adequately in all salinities and with best growth in terms of maximum cell density, specific growth rate (SGR) and biomass yield (g dry weight/L) at high illumination (8000 lux). The five species examined exhibited different responses in the salinities used, Amphidinium clearly does best in 20 ppt far better than 40 ppt and even more than 50 ppt. Nephroselmis and Tetraselmis grow almost the same in 20 and 40 ppt and less well in 60 ppt. Asteromonas does best in 100 ppt although it can grow quite well in both 40 and 60 ppt. Dunaliella grows equally well in all salinities (20-40-60 ppt). Concerning productivity as maximum biomass yield at the end of the culture period, first rank is occupied by Nephroselmis with ~3.0 g d.w./L, followed by Tetraselmis (2.0 g/L), Dunaliella (1.58 g/L), Amphidinium (1.19 g/L) and Asteromonas (0.7 g/L) with all values recorded at high light (8000 lux).

Two local marine cyanobacteria, Phormidium sp. and Cyanothece sp., were batch-cultured under 18–19.5 °C, at 40 ppt salinity, using white LED light of low (40 μmol photons/m2/s) and high (160 μmol/m2/s) intensity and, additionally, blue, green and red LED light. Yield was highest in high white light in both species (2.15 g dw/L in Phormidium, 1.47 g/L in Cyanothece), followed by green light (1.25 g/L) in Cyanothece and low white and green (1.26–1.33 g/L) in Phormidium. Green light maximized phycocyanin in Phormidium (0.45 mg/mL), while phycoerythrin was enhanced (0.17 mg/mL) by blue light and allophycocyanin by all colors (~0.80 mg/mL). All colors maximized phycocyanin in Cyanothece (~0.32 mg/mL), while phycoerythrin and allophycocyanin peaked under green light (~0.138 and 0.38 mg/mL, respectively). In Phormidium, maximization of chlorophyll-a (9.3 μg/mL) was induced by green light, while total carotenoids and b-carotene (3.05 and 0.89 μg/mL, respectively) by high white light. In Cyanothece, both white light intensities along with green maximized chlorophyll-a (~9 μg/mL) while high white light and green maximized total carotenoids (2.6–3.0 μg/mL). This study strongly indicates that these cyanobacteria can be cultured at the first stage under white light to accumulate sufficient biomass and, subsequently, under colored light for enhancing phycobiliproteins.

Skinned, vacuum-packed, postrigor gilthead sea bream fillets were frozen individually with characteristic freezing times of 2, 18, 74 and 640 min (times to cool the thermal center of the fillets from −1 to −7C). Immediately after freezing, the fillets were thawed, and their quality was evaluated with tests related to muscle integrity, myofibrillar protein denaturation and aggregation, lipid degradation and changes in tenderness. The muscle integrity indices (activities of α-glucosidase, β-N-acetyl-glucosaminidase and (β-hydroxy-acyl-coenzyme-A dehydrogenase and the amount and protein content of centrifugal tissue fluids) showed that the freezing process itself clearly affected the integrity of muscles. Freezing of fillets with characteristic freezing time of 74 min caused more damage to muscles and hydrolysis of lipids than the other freezing times. Adenosine triphosphatase (ATP) ase activities and Ca2+ sensitivity of actomyosin extracts suggested that the freezing process itself, but not the freezing times, caused structural damage to myofibrillar proteins. No difference in the levels of salt-soluble proteins and sulfhydryl contents in actomyosin extracts was found between the fresh and frozen fillets. Sensory evaluations showed that the cooked frozen fillets were less tender than the cooked fresh ones. PRACTICAL APPLICATION In commercial seafood industries, seafoods are frozen at a range of freezing times (rates) that depends mostly on the type of seafood, the type of freezer and freezer's operating conditions. Based on the work reported in the literature, freezing of seafoods at different freezing times may furnish favorable conditions for alterations in muscle structure, muscle proteins and lipids, and textural properties in general. These changes are related to alterations in quality of frozen seafoods and may affect their market. Therefore, knowledge of optimal conditions with respect to freezing rates for freezing commercially important seafoods, as farmed gilthead seabream is, is relevant to the seafood industry. This information can be obtained by experimental studies on changes in the chemical, biochemical, physical and sensory properties of seafoods frozen at different freezing times.