| Popis: |
Fatty acids, microelements and heavy metals are very important components in human nutrition. The objective of this study was to establish whetherthere was a difference in these constituents and a/so how thermal treatment influences the content and composition of fatty acids of freshwater white fish from ponds or river water. The samples investigated were as follows fishpond crucian carp (weed) and fish from the river Danube (mixed white fish). After dressing, separation, freezing and defrosting, one part of the fish was used for thermal treatment. Total lipids, microelements and heavy metals were determined in untreated and heat treated samples. Total lipid contents of in fishpond fish and Danube fish were 5.63 and 6.70 % respectively. A high proportion of unsaturated fatty acids was found regardless of the origin of the fish. Thermal treatment brought about a reduction in the polyunsaturated to saturated fatty acid ratio as follows from 2.53 to 0.58 for fishpond fish and from 2.00 to 0.47 for Danube fish. The contents of toxic elements in the fish meat were within the limits of norms defined by legal regulations. The contents of iron (Fe), copper (Cu) and zinc (Zn) in the meat of fish from fishponds and the Danube were: 11.52 and 10.97; 0.98 and 0.78; 25.96 and 13.28 ppm, respectively. The results obtained indicate that although there were some differences in composition of lipids and microelements between the investigated fish samples, from the aspect of nutrition they represent an important resource and might be used for making high quality and nutritively valuable products of the pate type. |
