UNIVERSITY of PADUA Evaluation of the Nutritional
Total Page：16
File Type：pdf, Size：1020Kb
UNIVERSITY OF PADUA DEPARTMENT OF COMPARATIVE BIOMEDICINE AND FOOD SCIENCE Master Course in Biotechnologies for Food Science Evaluation of the nutritional features of wild fish species in Santa Pola port (Es) used for human consumption with a related study of the presence of toxic contaminants Supervisor Prof. Mauro Dacasto Assistant supervisor Dr. Marina Santaella Pascual (Tecnology, Nutrition and Food Science) Dr. Maria Jesùs Periago Castòn (Tecnology, Nutrition and Food Science) Graduate Veronica Gelisio ID number 1036114 ACADEMIC YEAR 2013-2014 INDEX Abstract .............................................................................................................................. 1 Riassunto ………………………………………………………………………………………………………..……………… 2 Chapter I : Introduction ................................................................................................ 3 1.1 Nutritional value of fish ..................................................................................... 5 1.1.1 RDA (Recommended Daily Allowance) ……….…….….…....….……............ 6 1.2 Heavy metals and biomagnification ….....…………………….…….……………................. 7 1.2.1 Information about the present laws …….………………….….………............ 10 1.3 Description of the fish species ….........................……………………………….………...…. 12 1.3.1 Hake (Merluccius merluccius, Linnaeus 1758) ................................... 13 1.3.2 Greater forkbeard (Phycis blennoides, Brünnich 1768) ..................... 15 1.3.3 Red mullet (Mullus barbatus, Linnaeus 1758) .................................... 17 1.4 Area of study: Santa Pola port ….........…....................………...……………….……….…. 19 Chapter II : Aim of the thesis …….………...….….………...……………………………...................... 21 Chapter III : Materials and metods : ............................................................................. 22 3.1 Samples preapration .......................................................................................... 22 3.1.1 Material ............................................................................................... 22 3.1.2 Dissection ............................................................................................. 23 3.1.3 Shredding ............................................................................................ 25 3.2 Moisture analysis ............................................................................................... 25 3.2.1 Materials and equipment ................................................................... 26 3.2.2 Moisture analysis procedure ............................................................... 26 3.3 Search for the protein ........................................................................................ 28 3.3.1 Materials and equipment ................................................................... 28 3.3.2 Procedure general information ...…………….………………………................ 29 3.3.2.1 Sample preparation .............................................................. 29 3.3.2.2 Digestion phase ..................................................................... 30 3.3.2.3 Distillation of the digested sample ....................................... 32 3.3.2.4 Potentiometric titration by using a known acid ................... 34 3.3.2.5 Formula and calculation for the % of the raw protein ......... 35 3.4 Search for the lipids …......................................................................................... 36 I 3.4.1 Materials and equipment .................................................................... 36 3.4.2 Procedure of the search for the total lipids ....................................... 37 3.4.2.1 The 4 phases in detalis ........................................................ 39 3.4.2.2 Calculation of lipid percentage ............................................ 40 3.5 Determination of ash and samples preparation for ICP-AES analysis .............. 41 3.5.1 Materials and equipment ................................................................... 41 3.5.2 General information on the procedure ……………………………………………. 42 3.5.2.1 Incineration and ash calculation .......................................... 42 3.5.2.2 Acid hydrolysis of the ash ….................................................. 43 3.6 ICP-AES analysis ................................................................................................. 45 3.6.1 General information ............................................................................ 45 3.6.2 Analysis of mineral elements and heavy metals ……...……….………....... 47 3.7 Mercury analysis ................................................................................................. 50 3.7.1 Materials and equipment ................................................................... 51 3.7.2 Digestion of food samples ...................……......................................... 51 3.7.3 Analysis of the atomic fluorescence spectrophotometer (AFS) …..…. 54 Chapter IV : Results and discussion …………………………………………………………………………… 57 4.1 The statistical analysis ….………………………………………………………………………..……. 57 4.2 Results ………………………………………………………………………………………………………….. 57 4.3 Discussion ……………………………………………………………………………………………………… 69 4.3.1 Chemical composition ……………………………………………………………………. 69 4.3.2 Mineral component ………………………………………………………………………… 73 4.3.3 Heavy metals …………………………………………………………………………………. 78 Chapter V : Conclusions : ............................................................................................ 82 Chapter VI : Bibliography : .......................................................................................... 84 Chapter VII : Webliography : ……….………………………………………….................................... 94 II LIST OF FIGURES Figure 1. The biomagnification ……………………………………………………………………………………….. 9 Figure 2. Hake (Merluccius merluccius) ……………………………………………………………..………….. 14 Figure 3. Geographical distribution of Merluccius genus .................................................. 15 Figure 4. Greater forkbeard (Phycis blennoides) ……………………………………………….……………. 16 Figure 5. Geographical distribution of P. blennoides ……………………………………………………… 17 Figure 6. Red mullet (M. barbatus) …………………………………………………………………………………. 18 Figure 7. Geographical distribution of the M. barbatus species ……………………………………… 19 Figure 8. FAO zone 37 ……………………................................................................................... 20 Figure 9. Alcantarilla fish market ………………………………………………..………………………………….. 22 Figure 10. Fish dissection procedure …………………………………………………………………………. 24/25 Figure 11. On the left an example of the weighted sample and on the right samples put in the drying oven ……………………………………………………………………………………... 26 Figure 12. On the left a Kjeldhal digestor working; on the right a scrubber ……………………. 31 Figure 13. KjelticTM distiller ……………………..……………………………………………………………………… 32 Figure 14. On the left a sample at the beginning of the distillation. On the right the solution has already moved to the flask and we can notice the change of the colour mixture caused by the mixture pH change ……………………………………. 34 Figure 15. Sample subjected to basic acid titration ……………………………………………………….. 35 Figure 16. Overview of the phases for the extraction of total lipids content …………………. 38 Figure 17. Some details of Soxhlet extractor: on the left the first two phases, on the right phases 3 and 4 …………………………………………………………………………………………. 40 Figure 18. On the left: weighing the fresh sample; on the right: samples placed into the Program Controller S27 muffle furnace ……………………………………………………. 43 Figure 19. On the left reagents necessary for acid hydrolysis; on the right acid hydrolysis on heating plate ………………………………………………………………………………………………. 44 Figure 20. On the left material used to transfer a sample in a flask; on the right samples on the 10 mL falcons and ready for spectrometer analysis ………………………………. 45 Figure 21. Duo ICP-AES Thermo Scientific™ Made in England ………………………………………..… 47 Figure 22. Example of regression in lead analysis, in the range of 0.00049 to 6.4nm 220.353 mg L-1 ………………………………………………………………………………………………… 48 Figure 23. Example of a spectrum of ICP-AES emission obtained in Pb analysis at a wavelength of 220.353nm …………………………………………………………………………….. 50 Figure 24. Series of pictures representing the preparation procedure of the samples To place in the Microwave solvent Extraction lab station ……………………………. 52 III Figure 25. Microwave oven Milestone Ethos Sel model with representation of the loading of the samples ……………………………………….…………………………………………. 53 Figure 26. Atomic fluorescence spectrophotometer PSAnalytical Millennium system and some samples subjected to analysis ………………………………………………..……… 54 Figure 27. Atomic fluorescence spectrophotometer PSAnalytical Millennium system and some samples subjected to analysis ………………………..……………………………… 55 Figure 28. Representation of moisture time trend in M. merluccius, P. blennoides and M. barbatus with related significant differences p <0.05 indicated by the letters a-f ……………………………………………………………………………………………… 61 Figure 29. Representation of time trend for ash values recorded in M. merluccius, P. blennoides and M. barbatus with related significant differences p <0.05 indicated by the letters a-b …………………………………………………………………………..... 61 Figure 30. Representation of time trend for total protein content in M. merluccius, P. blennoides and M. barbatus. Significant differences in values were not observed …………………………………………………………………………………………………………. 62 Figure 31. Representation of time trend for lipid total content in M. merluccius, P.