Investigation on changes in the chemical composition of hot smoked Salmo trutta macrostigma, Dumeril 1858, stored different temperatures

Abstract

Effects on the chemical composition of different storage temperature of the Salmo trutta macrostigma, Dumeril 1858, living in our inland waters, were determined after applying hot smoking technologies to find out the suitability of these processing techniques for this species. Samples that were hot smoked and stored at 4.0 ±0.5oC were analysed 1, 7, 14, 21, 28, 36 and 51 days after the experiments started, while all the other samples were analysed after 1, 7, 14, 21, 28, 36, 60, 90, 120, 150 and 180 days. At each analysis session, samples were analysed for their water, total lipid, inorganic matter and salt contents, total fatty acid, TBA and TBV-N contents and for their pH levels. Fatty acids were analysed gas chromatographically. General chemical compositions in fresh and hot samples were also studied. Total fatty acid levels changed irregularly in hot smoked fish samples. TBA and TVB-N compounds increased with increasing storage time at all groups. Results of the gas chromatographic analysis revealed that fresh S. trutta macrostigma contained 316.3 μg/g unsaturated (ΣUFA) and 127.2 μg/g saturated (ΣSFA). In general an increase in the quantity of saturated and a decrease in unsaturated fatty acids was observed during the storage of all the hot smoked products. Maximum decreases in ΣMUFA (Mono unsaturated fatty acids) content were determined in DS samples upto day 51 (135.3 μg/g) and in DF samples (hot smoked and stored at –18±1 °C’de) upto day 180 (140.2 μg/g). The maximum decrease in ΣPUFA (Poly unsaturated fatty acids) level was observed in DS group (150.8 μg/g). According to results of the present study it can be concluded that in this study the hot smoked samples could be stored safely during the study period.