Jayasinghe, L.L.S.L.Wijesundara, W.M.N.M.Liyanage, N.P.P.Madage, S.S.K.2022-02-222022-02-222013http://www.erepo.lib.uwu.ac.lk/bitstream/handle/123456789/8417/30-AQT-Study%20on%20the%20Effect%20of%20Different%20Levels%20of%20Heat%20on%20the%20Quality%20of%20Dark%20muscle%20of%20.pdf?sequence=1&isAllowed=yCoastal and off shore marine production in Sri Lanka has an increasing trend. According to Department of Fisheries and Aquatic Resources, a catch of 417,220 metric tons was recorded in 2012. Yellow fin Tuna (Thunnus albacares) is included in large pelagic fish catch of Sri Lanka and it composed 10% of total marine catch in 2012. Yellow fin tuna (YFT) is mainly exported as Loins, Steaks, Centre cuts, Cubes, Medallions and Saku in processed form. Currently there are 27 European Union approved fish processing factories in Sri Lanka. Considerable parts of fish are removed as by-products during processing; this includes dark muscle, fins, skin, head and viscera parts. The amount of by-products produced during fish processing is vary between 40-75% of the total weight of fish according to the way of processing (Shahidi (1994), cited in Zapata et al., 2011). Though some value addition is done to these by-products there are plenty of opportunities to add value to by-products like YFT dark muscle. Thermal preservation is one of the current techniques used in value addition. Therefore, it is very important to know the quality changes of YFT dark muscle when they undergo thermal preservation techniques. Although many studies have been conducted to determine the initial quality of this muscle, still the quality changes with the different heat treatments are not studied. Therefore, objectives of this study were to evaluate the effect of different levels of heat treatments on the physical, chemical and organoleptic properties of YFT Dark muscle (DM). Methodology DM of YFT fish processed at Ceylon Fresh Seafood Private Limited in Ja-Ela were collected and transported with gel ice at 4°C to Industrial Technology Institute (ITI) and stored in -18 °C until used for the experiment. Experiment was conducted as three stages as fresh fish quality determination, pre-trial and heat treatment study using 0.5 kg, 1.5 kg and 2 kg amounts respectively. For fresh fish quality determination, physical properties including colour (Minolta Chroma meter CR-200, Japan), texture (as firmness using GUSS fruit texture analyser, United States of America) and water holding capacity and chemical properties including moisture, ash, crude protein, crude fat, water soluble protein content, pH of 10% muscle solution and water activity (AquaLab® apparatus-Series 3 TE, USA) of fresh muscle were determined by following respective AOAC methods. Colour and texture of approximately 3×2.5×1 cm sized undisturbed muscle chunks were recorded. Sensory evaluations (acceptance test with five point hedonic scale) were conducted with seven trained panellists of sensory panel of ITI using fish chunks as pre-trials. Those chunks were marinated overnight with 2% salt, to determine the best deep frying and boiling durations. As time durations 05, 10 and 15 minute durations were selected and frying was done in coconut oil at 185 ºC while boiling was performed at 100 ºC. For the heat treatment study, fish chunks were prepared as in pre-trial and those were boiled and deep fried for five minutes. Fish chunks were canned in A-1 sized cans with2% salt solution at 121.1 ºC for ten minutes. Finally the chemical and physical properties of heat treated DM were determined. Final organoleptic quality of the heat treated DM was evaluated by nine trained panellists of ITI using acceptance test with nine point hedonic scale. Physical and chemical quality data were analysed using one way analysis of variance procedure in Minitab 16 statistical package. Sensory evaluation data were analysed using Friedman non parametric test in SPSS 22.0 statistical package. All mentioned significant differences are given at P<0.05.enAnimal SciencesAquaculture and FisheriesAquatic ResourcesFishfish IndustryOther