Beta-carotene isomer composition of sub- and supercritical carbon dioxide extracts. Antioxidant activity measurement

In the present work sub- and supercritical extraction conditions using carbon dioxide were studied in order to obtain extracts with different compositions from the green microalgae Dunaliella salina. Different compositions of beta-carotene isomers were identified in the extracts by using HPLC-DAD. Also, antioxidant activity of the extracts was measured using a TEAC assay. An experimental design was applied considering two factors, extraction pressure and temperature, in a wide range of values, trying to maximize the extraction yield. Higher yields were obtained at high pressures and low temperatures, that is, at higher CO2 densities. Attempts were made to correlate the antioxidant activity of the extracts with their chemical composition by means of principal component analysis. A certain relationship was found between their antioxidant activity and the isomeric composition of beta-carotenes. As a result, an original equation is proposed to predict the antioxidant activity of extracts from D. salina in terms of the ratio 9-cis-beta-carotene/all-trans-beta-carotene, the concentration of alpha-carotene, and, especially, the concentration of 9-cis-beta-carotene.     

A sensory and nutritional validation of open ocean mussels (Mytilus galloprovincialis Lmk.) cultured in SE Bay of Biscay (Basque Country) compared to their commercial counterparts from Galician Rías (Spain)

Mussel shell biometry, nutritional quality as well as consumer sensory evaluation of experimental open ocean cultured mussel Mytilus galloprovincialis (Lamarck 1819) were analyzed and compared to that of commercial mussels from Galician Rías available in the local market. Both mussel products were of the same commercial size. In this study, open ocean mussels were significantly higher and wider than those of Galician Rías. In addition, with the exception of ash content, both mussel products showed similar biochemical composition. Regarding fatty acid profiles, however, statistical differences were detected. These differences were not fully reflected in the sensory assessment. In terms of consumer acceptability, both mussel products were considered equally satisfactory.

     

Analysis of culture production and growth rate patterns of mussel (<Emphasis Type="Italic">Mytilus galloprovincialis</Emphasis> Lmk.) cultured in the open ocean of the SE Bay of Biscay for the commercial product development

Mytilus galloprovincialis Lmk. mussels were cultured at two culture depths in a submerged longline system, located in the SE Bay of Biscay, from June 2013 to August 2014. The Von Bertalanffy Seasonal Growth Function (VBSGF) of the original seeded batch, without newly settled seed, at each culture depth was assessed. Mussels maintained their reached size during the slow growing months and size increased thereafter. In addition, to test both culture depth scenarios for resource management, the production of commercial pieces (“small” and “large” mussels) in quantity (mussel classification) was assessed. VBSGF output proved that commercial mussels may well be harvested throughout the year in the studied site. The culture period required to produce mussels of a commercial size was 1 to 1.5 years, depending on seeding date.     

Isolation of nuclei from a marine dinoflagellate

By means of a medium containing dextran, nuclei were isolated in high yield from cells of Gymnodinium nelsoni, a marine dinoflagellate. Most of the DNA, but less than onetenth of the RNA, of the original cells was recovered in the purified nuclei. The nuclei appeared substantially intact as observed by light or electron microscopy. The isolated nuclei were capable of incorporating tritiated uridine triphosphate into material insoluble in cold acid. The general procedure was found to be applicable also to two species of diatoms.     

Effects of temperature on development and mortality of Atlantic mackerel fish eggs

The development of Northeast Atlantic mackerel (Scomber scombrus) eggs, obtained from artificial fertilisation during the spawning season in the Biscay Bay area, was monitored at five temperatures (ranging from 8.6 to 17.8 °C). The times to intermediate stages (III–V) and total hatching, obtained in this study, agree with the results of previous studies undertaken some years ago. However, the times over stages IA, IB and 50% hatching indicate that development rates differed significantly between the studies; this could be related to an effect of the previous thermal history of the eggs, or to experimental biases. Daily mortality (Z) during the embryonic period was found to vary between 0.17 and 0.38, using traditional exponential decay models. The estimates of mortality rate were found to range consistently with those derived from previous studies on Northwest Atlantic mackerel eggs without predation. However, the shape of the survivorship-curve during the development pursued in this study has indicated that mortality is not constant in time. Similarly, the suitability of an exponential model to describe daily mortality should be considered.     

Variability of the reproductive cycle in estuarine and coastal populations of the mussel Mytilus galloprovincialis Lmk. from the SE Bay of Biscay (Basque Country)

Mussel commercial production depends on wild populations to obtain the seed. Therefore, any new farming initiative needs deep knowledge on reproductive cycle of native mussel populations. The reproductive cycle of Mytilus galloprovincialis Lmk. from five sites, three estuarine and two coastal, along the coast of the Basque Country were assessed using gonad index and stereology over 2 consecutive years (2010 and 2011). Sex ratios, developmental stages of gonads , as well as reserve tissue cycle were analyzed. The onset of gametogenesis was observed from winter to spring, with spawning occurring from spring till summer. A resting phase followed with an increase in reserve tissues (adipogranular cells) was observed in fall. Mussels stayed ripe during winter until favorable environmental conditions were met in spring. Differences in reproductive cycles were found among populations, and also, year-to-year variability was observed within each population. In two of the studied sites asynchrony in the timing of spawning was observed between genders. These timing differences, however, did not prevent mussels at those sites from reproducing successfully. The Bidasoa estuary points to the potential of such studied sites for becoming the main source of wild mussel spats for future expected commercial mussel farming in the Basque Country. To ensure year-to-year maximum reproductive output, however, wild mussels harvest should be avoided from spring to the end of summer in this region.

     

Plant Growth and Sugars Content of Agave americana L. Cultivated with Vermicompost and Rock Phosphate and Inoculated with Penicillium sp. and Glomus fasciculatum

The objective of this study was to investigate the effect of vermicompost, rock phosphate, Glomus fasciculatum (arbuscular mycorrhizal fungi), and Penicillium sp. (phosphate solubilizing fungi) on growth; mycorrhization percent; fructan, sucrose, glucose, and fructose contents in leaves and stem of Agave americana L. Experiments were done according to an orthogonal experimental design L₈ with four variables at two levels: vermicompost (0 or 10 g per plant), rock phosphate (0 or 1 g per plant), G. fasciculatum (0 or 1 × 10⁶ spores per plant), and Penicillium sp. (0 or 1 × 10⁹ spores per plant). Vermicompost affected stem dry weight; the fructan, glucose, and fructose in stem; and mycorrhization percent in roots. Rock phosphate and Penicillium sp. increased the mycorrhization percent. Co-inoculation of Penicillium sp. and G. fasciculatum increased A. americana plant growth. The results obtained suggested a synergistic interaction between the arbuscular mycorrhizic fungi and the phosphate solubilizing fungi.