Browsing by Author "Kariyawasam, M.G.T.R."

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    Development of a Simple Nontoxic Method to Extract Crude Fish Oil from Yellowfin Tuna (Thunnus albacares) Offal
    (Uva Wellassa University of Sri Lanka, 2019-02) Basuru, G.M.V.T.; Kariyawasam, M.G.T.R.; Alakolanga, A.G.A.W.; Abeyrathne, E.D.N.S.
    Among world fish processing industry yellowfin tuna is a dominating species that is responsible for high amount of waste generation during processing which makes a high level of by-product. Fish by-products consist with omega-3 poly unsaturated fatty acids that are vital in food and pharmaceutical industry. The study was targeted to develop an effective fish oil extracting method from yellowfin tuna gut comparing with a current existing extraction technique. The determined proximate composition of yellowfin tuna gut showed 4.87±0.2% of crude fat. The research was conducted with completely randomized design (CRD) with two treatments; wet press method (rendering) and the solvent extraction method. As the solvents Chloroform/Methanol (standard), Acetone, Petroleum ether, n-Hexane, n-Butanol and Ethanol were used separately in 1:2 ratio (Gut sample: Solvent). Finally fish oil yields were calculated on percentages and analyzed the chemical property indices (Iodine value, Peroxide value and Acid value) of extracted fish oil. The results revealed that the highest yield (88.63±2.76%) was obtained in wet press method. In solvent extraction Acetone performed the highest yield (75.26±1.85%) showing the significant difference in comparison with oil yields of Petroleum ether, Hexane, n-Butanol and Ethanol (p<0.05).Iodine value of extracted fish oil from wet press method, Chloroform/Methanol, Acetone, Petroleum ether, n-Hexane, n-Butanol and Ethanol were 109.99±0.57, 103.94±0.56, 104.70±0.47, 104.53±0.74, 103.43±0.37, 106.15±0.86, and 105.83±0.68 respectively. The obtained peroxide value (2.98±0.05) and Acid value (1.04±0.02) of wet press method also indicated higher values than the solvent extraction method which assures that solvent extraction had a low hydrolysis and low oxidation in comparison with the wet press method. As conclusion extraction with acetone is better comparing the quality of the oil extracted.
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    Extraction of Crude Bone Collagen from Yellowfin Tuna (Thunnus albacares) and Determination of Anti-oxidative Activity of Its Hydrolysates
    (Uva Wellassa University of Sri Lanka, 2018) Wijekoon, W.M.M.P.; Aruppala, A.L.Y.H.; Kariyawasam, M.G.T.R.; Abeyrathne, E.D.N.S.
    Fish bones are significant part of fish processing by-product and rich source of collagen proteins. Utilization of yellowfin tuna bones are important economically as well as environmentally. Objective of this research was to extract crude collagen from yellowfin tuna bones and to identify the anti-oxidative activities of its hydrolysates which can be a potential natural anti-oxidative agent in food industry. Acid-pepsin soluble collagens were extracted from fresh yellowfin tuna bones. As with the pre-treatment process EDTA and citric acid were tested to decalcify. Extracted collagens from two treatments were subjected to the hydrolysis using protease enzyme with different time combinations (0, 3, 6, 9, 12, 24 h) at 37 °C followed with heat inactivation at 100 °C for 15 minutes. Antioxidant activity of the best hydrolysates were evaluated using thiobarbituric acid reactive substances (TBARS) assay and 2,2-dipheny1-1-picrylhydrazyl (DPPH) free radical scavenging activity method. All treatments were replicated (n = 3). Resulting extracts with citric acid treatment (1.23±0.05%) showed higher yield compared to the EDTA treatment (0.62±0.18%) (p < 0.05). Both treatments showed similar band patterns with 08% SDS-PAGE gel electrophoresis confirming the extracted collagen are same. Hydrolysates produced after incubating for 3 hours at 37 °C followed with heat inactivation was selected as the best (p < 0.05). The results showed that collagen hydrolysate of yellowfin tuna bones inhibited lipid oxidation in oil emulsion system and also control free radicals (DPPH). TBARS results of EDTA and citric acid treatment showed no significance difference with the control(p > 0.05). EDTA (86.14±1.88%) and citric acid (87.92±7.72%) treatments showed DPPH free radical scavenging activity compared with ascorbic acid (89.10±0.64%). These results suggest that hydrolysates produced from yellowfin tuna bones with citric acid can be used as a potential natural antioxidant agent in food industry.
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    Production of Biodiesel from Yellowfin Tuna (Thunnus albacares) Fish Skin Wastage
    (Uva Wellassa University of Sri Lanka, 2018) Amangilihewa, G.V.; Mahaliyana, A.S.; Kariyawasam, M.G.T.R.; Abeyrathne, E.D.N.S.; Etampawala, T.N.B.
    Yellowfin tuna (Thunnus albacares) is one of the major exporting fish species in Sri Lanka. Approximately 50% of the total large pelagic catch in Sri Lanka constitutes tuna-like fish species and usually fillets, steaks, cubes are exported. The rest, which is approximately 1/3 of the harvest is discarded which contain head, skin, tail, viscera and fins. Roughly 5000 tons of fish waste are generated every year in Sri Lanka. Dumping such waste in to the environment can cause various environmental problems. This study was focused to add value to such waste by producing biodiesel as an alternative energy source for petroleum. Tuna fish skins were collected from local processing factory and brought to the laboratory under 4 °C and cut in to small pieces. Fish oil was extracted using different solvents; absolute ethanol, ether, nhexane and 1:1 mixture of ethanol and water using ultra sonication and soxhlet extraction method. Fatty acid profile, energy and the yield was calculated. Accordingly there were no any significant difference in yield of the extracted oil with single solvents used (p > 0.05). But ether was selected as the best solvent (3.24 g±0.61). Among the two methods, Soxhlet method showed the highest oil yield (20 mL/kg of fish skin). Fish oil profile was obtained by using Thin Layer Chromatography (TLC) and Gas Chromatography-Mass Spectroscopy (GC-MS). The extracted oil was used to produce biodiesel using single step transesterification with potassium methoxide. The percent conversion of oil in to biodiesel was 88%. Fourier Transmission Infrared (FTIR) Spectroscopy method was used to characterize the fish oil as well as the biodiesel. The energy capacity of the synthesized biodiesel was measured using a Differential Scanning Calorimeter. All the test results were benchmarked against the commercially available petrochemical based diesel. Accordingly, ether soxhlet separation can be used as a potential biodiesel production from Yellowfin tuna fish skin.