PROXIMATE COMPOSITION OF EDIBLE SEA URCHIN PARACENTROTUS
Chemical analyses on edible sea urchin Paracentrotus lividus (Echinoidea) gonads legally (L) and illegally (I) sold in Sardinia (Italy) were carried out during the fishing season 20082009. Statistical tests performed on moisture, ash, crude protein, lipid and carbohydrate content detected significant differences between L and I samples, but also among roe illicitly commercialised (I) by ambulant vendors in different Sardinian coastal districts. Key-words: chemical composition, roe fisheries, Paracentrotus lividus, Mediterranean Sea. Introduction The purple sea urchin Paracentrotus lividus (Lamarck, 1816) is an Echinoid of commercial importance with a high market demand for its roe. In Sardinia, the harvesting of this species is intensively practised (Pais et al., 2007) and, with the exception of a few authorised dealers, it is illicitly sold without veterinary inspection. Since a recent study has demonstrated significant differences in the microbial content of sea urchin roe legally and illegally commercialised in a number of Sardinian coastal districts (Floris et al., 2009), the aim of this work was to compare their proximate composition in order to highlight further differences in their quality traits. Materials and methods Sea urchin roe collected in the Gulf of Oristano and packed in glass jars by an authorised seafood dealer (hereafter L), and roe samples purchased from unauthorised ambulant vendors (hereafter I) in the districts of Alghero, Sassari and Cagliari were analysed during the fishing season 2008-2009. Three samples from each group were tested. Every sample was initially homogenised, then the moisture content was determined after drying in an oven at 105 °C for 24 h. Ashes were evaluated after combustion at 550 °C for 12 h in a muffle furnace. Crude protein was obtained by the Kjeldhal method (AOAC, 1990), and total lipids were quantified through the method proposed by Folch et al. (1957). Finally, carbohydrate content of each sample was determined by difference. All analyses were carried out in triplicate, and the results were expressed as percentages of the wet weight (%WW). One-way Analysis of Variance was used to detect putative differences between the roe analysed and the Student-Newman-Keuls (SNK) test was used for post-hoc comparisons. Results Proximate composition of Paracentrotus lividus roe examined is reported in Tab. 1. The sea urchin gonads legally packed (L) in Oristano showed a significant higher moisture content (p<0.01) than those illicitly sold (I) in Alghero, Cagliari and Sassari districts, respectively. On the other hand, ash, crude protein, total lipid and carbohydrate content of the L group was always lower (Tab. 1) than those illegally commercialised by ambulant vendors. For these latter variables, however, the SNK test revealed significant differences (p<0.01) also among the I roe samples, being those from Cagliari always characterised by higher mean values (except for ash content). Proximate composition of edible sea urchin P. lividus roe commercialised in Sardinia 391 Tab. 1 Proximate composition (% wet weight±SD) of Paracentrotus lividus gonads (L=legal; I=illegal). Different superscripts indicate significant differences (p<0.01). Composizione centesimale (% peso umido±DS) delle gonadi di Paracentrotus lividus (L=legali; I=illegali). Esponenti diversi indicano differenze significative (p<0,01). Oristano (L) Alghero (I) Cagliari (I) Sassari (I) Moisture 85.00±0.41a 84.06±0.76b 81.77±0.43c 84.27±1.18b Ash 1.88±0.03c 2.10±0.12b 2.21±0.03b 2.35±0.25a Crude protein 10.96±0.21c 11.64±0.65b 12.20±0.28a 10.60±0.68c Lipid 1.87±0.09c 1.85±0.05c 2.17±0.08a 1.98±0.09b Carbohydrate 0.29±0.12c 0.35±0.10c 1.65±0.18a 0.80±0.27b Conclusions This study evidenced significant differences in proximate composition of Paracentrotus lividus roe legally and illegally commercialised in several Sardinian coastal zones. In particular, sea urchin gonads packed by an authorised seafood dealer showed a higher content of moisture, probably due to intense washing procedures before packaging (De la Cruz-García et al., 2000). Previous studies have highlighted seasonal variations in the chemical composition of raw sea urchin roe from both Mediterranean (Dincer & Cakli, 2007; Mol et al., 2008) and Atlantic areas (Montero-Torreiro & Garcia-Martinez, 2003), but little is known about quality changes due to handling or alteration of the product. In fact, while P. lividus gonads illicitly sold can have different quality traits attributable to different time periods from harvest to sale (the so-called “food miles”), further research is needed to test if legal glass jars storage can modify the chemical-bromatological properties of the purple sea urchin roe. Acknowledgements The Authors are grateful to the “Società Cooperativa Ittica Arborea” a.r.l. References AOAC (1990) Official methods of analysis of the Association of Official Analytical Chemists. 15th ed. A.O.A.C. International, Arlington, VA: 1200 pp. DE LA CRUZ-GARCÍA C., LÓPEZ-HERNÁNDEZ J., GONZÁLEZ-CASTRO M.J., RODRÍGUEZ-BERNALDO DE QUIRÓS A.I., SIMAL-LOZANO J. (2000) Protein, amino acid and fatty acid contents in raw and canned sea urchin (Paracentrotus lividus) harvested in Galicia (NW Spain). J. Sci. Food. Agric., 80 (8): 1189-1192. DINCER T., CAKLI S. (2007) Chemical composition and biometrical measurements of the Turkish sea urchin (Paracentrotus lividus, Lamarck, 1816). Crit. Rev. Food Sci. Nutr., 27 (1): 21-26. FLORIS R., FOIS N., MANCA P., MANCA S., MONTISCI S., PAIS A. (2009) Analisi microbiologiche su gonadi del riccio di mare commestibile Paracentrotus lividus commercializzate in Sardegna. Biol. Mar. Mediterr., 16 (1): 398-399. FOLCH J., LEES M., STANLEY G.H.S. (1957) A simple method for the isolation and purification of total lipids from animal tissues. J. Biol. Chem., 226 (1): 497-509. MOL S., BAYGAR T., VARLIK C., TOSUN S.Y. (2008) Seasonal variations in yield, fatty acids, amino acids and proximate compositions of sea urchin (Paracentrotus lividus) roe. J. Food Drug Anal., 16 (2): 68-74. MONTERO-TORREIRO M.F., GARCIA-MARTINEZ P. (2003) Seasonal changes in the biochemical composition of body components of the sea urchin, Paracentrotus lividus, in Lorbé (Galicia, north-western Spain). J. Mar. Biol. Ass. U.K., 83 (3): 575-581. PAIS A., CHESSA L.A., SERRA S., RUIU A., MELONI G., DONNO Y. (2007) The impact of commercial and recreational harvesting for Paracentrotus lividus on shallow rocky reef sea urchin communities in North-western Sardinia, Italy. Estuar. Coast. Shelf Sci., 73 (3-4): 589-597.
Using early life stages of marine animals to screen the toxicity of priority hazardous and noxious substances
This study provides toxicity values for early life stages (ELS) of two phylogenetically distinct marine animal taxa, the sea urchin (Paracentrotus lividus), a deuterostome invertebrate, and the turbot (Scophthalmus maximus), a vertebrate (teleost), when challenged by six hazardous and noxious substances (HNS): aniline, butyl acrylate, m-cresol, cyclohexylbenzene, hexane and trichloroethylene. The aim of the study was to provide preliminary information on toxic effects of representative and relevant priority HNS to assess the risk posed by spills to marine habitats and therefore improve preparedness and the response at the operational level. Selection criteria to include each compound in the study were (1) inclusion in the HASREP (2005) list; (2) presence on the priority list established by Neuparth et al. (2011); (3) paucity of toxicological data (TOXnet and ECOTOX) for marine organisms; (4) behaviour in the water according to the categories defined by the European Behaviour classification system (GESAMP 2002), by selecting compounds with different behaviours in water; and (5) physicochemical and toxicological properties, where available, in order to anticipate the most toxic compounds. Aniline and m-cresol were the most toxic compounds with no observed apical effect concentration (NOAEC) values for sea urchin ranging between 0.01 and 0.1 mg/L, followed by butyl acrylate and cyclohexylbenzene with NOAECs ranging between 0.1 and 1.0 mg/L and trichloroethylene with NOAEC values that were in the range between 1 and 10 mg/L, reflecting their behaviour in water, mostly vapour pressure, but also solubility and log Kow. Hexane was toxic only for turbot embryos, due to its neurotoxic effects, and not for sea urchin larvae, at concentrations in the range between 1 and 10 mg/L. The concentrations tested were of the same order of magnitude for both species, and it was observed that sea urchin embryos (length of the longest arm) are more sensitive than turbot eggs larvae (hatching and cumulative mortality rates) to the HNS tested (except hexane). For this specific compound, concentrations up to 70 mg/L were tested in sea urchin larvae and no effects were observed on the length of the larvae. Both tests were found to be complementary depending on behaviour in water and toxicity target of the compounds analysed.
Exploring interculturally competent teaching in social sciences classrooms
Abstract This paper explores a grounded research-based framework for intercultural competence and discusses the implications of interculturally competent teaching in the classroom and beyond. Given the importance of teachers being interculturally competent in today’s diverse classrooms, a number of questions, based on the framework, are presented, which guide teachers in reflecting upon their own teaching practice and the ways in which they integrate aspects of intercultural competence into their classrooms. The paper also provides some examples from the USA of ways in which intercultural competence development is being addressed in teacher training.