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.
Chemical Composition and Biometrical Measurements of the Turkish Sea Urchin (Paracentrotus Lividus, Lamarck, 1816)
We determined the monthly percentage values of biochemical components in paracentrotus lividus, for a 6-month period, and evaluated the findings in relation to seasonal fluctuations in water temperature and weather. Our study is the first to present a long-term biochemical profile of p. lividus in Turkey. They contained an average varied between 78.36 and 80.93 7% for moisture, 1.5 and 1.7% for ash, 2.37 and 4.27% for lipid, 9.26 and 11.75% for protein, and 1.95 and 2.53% for carbohydrate. Significant seasonal differences in sea urchin weight were noted between the winter and the summer months. Biometrical height measurements were done according to four criteria: total height, main height, diameter, and width. Weight measurements were done according to two criteria: living weight and weight of the roe. Also chemical composition analyses have been done in the parallel time periods of measurements. As a result of this study it has been determined that the spawning period of the sea urchin Paracentrotus lividus is in the time period between February and July. Amino acid contents of the Paracentrotus lividus were also determined.
Évolution des constituants biochimiques des principaux compartiments de l'oursin Arbacia lixula (L.) au cours d'un cycle sexuel et effets d'un jeûne de courte durée au cours de la maturation sexuelle
Resume Des experiences de jeune au cours de 2 periodes du cycle sexuel, repos et maturite, ont ete effectuees pour determiner le sens des variations a court terme des reserves du test, des gonades et du tube digestif, susceptibles de se produire dans les conditions naturelles. Des mesures de respiration et une estimation des calories que peuvent fournir la transformation des constituants biochimiques ou des differences significatives de niveaux ont ete notees, ont permis de determiner dans quelle mesure les besoins du metabolisme standard etaient couverts par l'utilisation de ces reserves. Les variations annuelles des pourcentages de proteines, glucides et lipides du test, des gonades et du tube digestif ont ete suivies de septembre 1973 a mai 1974. Un accroissement des proteines gonadiques a ete observe du debut de la periode de croissance a la fin de la maturite tandis que les glucides et les lipides des gonades augmentent principalement au cours de la croissance. Les glucides du tube digestif augmentent au cours de la periode de croissance des gonades (hiver) et les lipides au moment de la maturite (printemps). La quantite d'energie liberee par les 3 compartiments a la mort de l'oursin a ete estimee.