Browsing by Author "Wijesundara, W.M.N.M."

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    Determination of Sensory, Microbiological, Physio-chemical Quality and Shelf life of Portioned Chicken Meat under Display Condition at Market Stage
    (Uva Wellassa University of Sri Lanka, 2013) Nilanka, S.L.P.; Wijesundara, W.M.N.M.; Kekunamullage, P.
    Sri Lankan meat processing industry has been rapidly developed since last decade. With increasing market demand they develop various portioned meat products to the market fulfilling the customer requirement. Meat processors recently noticed that during display condition at market stage quality of the products were considerably changed. The aim of this study was to evaluate the physiochemical, microbial, sensory quality changes and shelf life of portioned chicken meat in three commercial brands at display condition (-4 ˚C to +4 ˚C) during 9 days. During the storage period pH value, water holding capacity (WHC), sensory attributes and microbial count were measured in 3 days interval over 10 days. Statistical evaluation was performed using one way ANOVA, general linear model and Friedman test. Gradual and proportional increment of pH values (between 6.14 ± 0.51 and 6.93 ± 0.57) were observed in tested commercial brands of portioned meat samples during the storage time. Furthermore, WHC values were shown significant reduction (between 62.55 ± 0.50 and 55.32 ± 0.02) in all portioned meat samples during the storage time. Total plate counts were increased (p>0.05) in day of storage whereas coliform bacteria also followed the same pattern. However, Escherichia coli were not found in any of sample analyzed. Total bacteria count in portioned chicken meat samples were changed from from day 0 to day 9 of storage. The results showed a gradual and proportional decrease of sensory quality in all portioned meat samples during the storage time (P<0.05). In conclusion, overall results of the study, number and diversity of bacteria species, pH, WHC and sensory quality of portioned chicken meat significantly change with the storage time under display condition at the market level. Also above quality changes significantly difference among three different commercial brands. To assure the quality of portioned chicken meat, it should not exceed five to six days in display condition (kept on -4 ˚C to +4 ˚C) at market stage.
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    Determination of the Effect of Coconut Shell Extracted Carbon Monoxide on the Quality of Frozen Yellow Fin Tuna (Thunnus albacares) Products
    (Uva Wellassa University of Sri Lanka, 2013) Jayasinghe, J.M.P.; Wijesundara, W.M.N.M.; Liyanage, N.P.P.; Wijesena, G.K.C.P.K.
    Seafood provides the world's prime source of high-quality protein to the consumers and processed frozen and fresh fish products account for major portion of the diets. Prolonged shelf life and fine quality give the advantages to the frozen fish products in the market and bright red color is used as an indicator of high quality in yellow fin tuna (Thunnus albacares). Carbon monoxide (CO) either alone or as part of a filtered process, is being applied to seafood to maintain the desirable color attributes. CO complexes with the heme-iron of myoglobin, forms a stable red pigment, carboxymyoglobin. The heme-proteins are strong catalysts of lipid oxidation in muscles and reduced heme-protein may suppress the lipid oxidation and other off odour and flavour production (Faustman et al., 1989). CO or filtered smoke is capable of retarding the microbial growth of the muscle (Kristinsson et al., 2008). In Sri Lankan context, coconut shells can be used for processing of filtered smoke with CO. The present study evaluates the effect of coconut shell extracted filtered smoke, a low cost source of CO on the chemical, physical, microbiological and sensory quality attributes of yellow fin tuna (Thunnus albacares). Methodology The study was carried out in a specially designed experimental laboratory of the Global Sea Foods (Pvt) Ltd. Imported grade “A” frozen yellow fin tuna (Thunnus albacares) from 57 Food and Agriculture Organization of the United Nations (FAO) area caught by long lines was used for the study. Average thickness and weight of the processed steaks for the experiment were respectively 22±1.2 mm and 170±6 g. CO was extracted from coconut shells following the Kowalski and William (1999) (United States Patent 5972401) process of making super purified smoke using organic material. CO free, 15%, 30%, 45%, 60% and 75% CO concentrations were used as treatments and CO injected steaks were stored under 4 ˚C for 48 hours and subsequently individually vacuum packed. Complete randomized design (CRD) was adopted for the experiment. Random number table (SLS, 428) was adopted to select the steaks for treatment in five replicates. Treated steaks were stored under -18 ˚C for 2 days and frozen steaks were subjected to analysis for chemical, physical, microbiological and sensory attributes. 15 trained panelists were used for sensory analysis and standards and criteria that were developed by the National Oceanic and Atmospheric Administration and U.S. Department of Commerce (USDC/NOAA) seafood analysts were adopted. All results were reported as means and the significance of the differences were determined by one-way analysis of variance (ANOVA) followed by tukey’s tests for the comparison of data with 5% level of significance. Minitab 16 statistical software and Microsoft Excel 2010 (Microsoft Corp) were used for the statistical analysis. Results and Discussion Chemical, physical, microbiological and sensory quality attributes were analyzed to determine the effect of coconut shell extracted CO on the quality of frozen Yellow fin tuna products. Result showed that there was no significant difference among the histamine level of different CO concentration treated frozen steaks (p>0.05) indicating that decomposition of histidine in to histamine was not affected by the treatment of coconut shell extracted CO smoke.
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    Study on Antioxidant and Antimicrobial Effect of Garlic (Allium sativum) in Garlic Incorporated Chicken Sausages
    (Uva Wellassa University of Sri Lanka, 2013) Herath, H.M.H.M.; Wijesundara, W.M.N.M.
    Meat is the most naturally occurring nutrient dense food stuff in the world (Kinsman et al., 1994). With the theme of value addition, manufacturing sausage is one of the oldest forms of processed meat product with various additives (Raju et al., 2003). Antioxidants are used in processed meat products with the aim of increasing the shelf life. The most common antioxidants used in food preservation are synthetic, such as butylatedhydroxytoluene (BHT), butylatedhydroxyanisole (BHA).With the reveal of adverse health effects of synthetic antioxidants by the researchers the food processors have focused to use natural substances which have antioxidant and antimicrobial effect (Ahmed et al., 1986). Garlic (Allium sativum) is one of the most commonly used ingredients as a flavor enhancer for sausage. In addition to flavoring, garlic is appreciated for its medicinal properties. Allicin is the main biologically active component of fresh garlic that affect antioxidant activity (Ankri and Mirelman, 1999). This study was carried out to determine the suitable garlic form and concentration of garlic in chicken sausages to determine the antioxidant effect of garlic against lipid oxidation and antimicrobial effect. Methodology Control recipe for chicken sausage was prepared by conducting several preliminary trials using mincing chicken meat, salt, vegetable oil, rusk powder, spices and BHA, as an antioxidant. The ingredients were allocated according to the SLSI standards and followed the standard sausage producing procedure according to the Toldra (2010). The suitable BHA level was determined according to the regulations in toxics A to Z: A Guide to Everyday pollution hazards (2006). The amount of BHA used in the control sample was 0.1 g per 1 kg of meat. Furthermore, developing control sausage recipe from all the preliminary trials was by sensory evaluation using 32 untrained panelists. The garlic was allocated according to the SLSI standards, which mentioned as 0.05% per 1 kg of meat. Two experiments were conducted to determine the suitable and acceptable form of garlic for sausages recipe as fresh garlic or garlic powder. Each experiment consisted of 2 sub experiments and 3 replicates were prepared for each experiment. For determination of fresh garlic level (experiment 1) 10 g, 20 g, 30 g and 40 g was allocated for each 1 kg of chicken meat sausage. For the determination of garlic powder form (experiment 2) 3 g, 6 g, 9 g, 12 g was used for 1 kg of chicken meat. With several sensory evaluations contained optimal level of garlic powder and fresh garlic was determined from 5 g, 6 g, 7 g, 8 g and 9 g with powder and 10 g, 20 g, 30 g and 40 g with fresh form using 32 untrained panelists. Changes in chemical, physical, sensory and microbiological parameters of prepared sausages with fresh garlic and powder garlic which stored immediately in refrigerator were analyzed over a period of 40 days. Proximate composition, pH, water holding capacity (WHC), and total plate count were determined in 3 days interval over the storage period for both treatments according to standard procedures (AOAC, 1995). Furthermore, total plate count (TPC) as in AOAC (1995) and Thio barbituric acid (TBA) value as described by Buege and Aust (1977) were analyzed in weekly intervals. As sensory characteristics of sausages, appearance, odor, color, taste and overall acceptability were evaluated by 32 untrained panelists. For each analysis 3 replicates were prepared and used. Statistical analysis for chemical and physical properties were analyzed though one way ANOVA using statistical software system and sensory data by Friedman test using MINITAB 15 statistical software package at the 95% confident interval.
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    Study on the Effect of Chemical, Microbiological and Organoleptic Parameters Related to the Flesh Colour of Yellowfin Tuna (Thunnus albacares)
    (Uva Wellassa University of Sri Lanka, 2013) Rajapaksha, R.V.D.N.; Wijesundara, W.M.N.M.; Thushari, G.G.N.; Weththasinghe, M.P.
    The fishing industry is particularly important for Sri Lankans for the domestic supply and there is also a small but growing export market for high value products. Yellowfin tuna is one of the most important fish species in Sri Lankan export market (Amarasiri et al., 2004). Yellowfin tuna is sold as fresh in local markets and exported as frozen, chilled or fresh products. The local market is highly regulated and price oriented with low emphasis on quality. They sold products in fresh form with little or no processing other than drying. However, the export market is characterized by demand for quality and high prices. So the freshness of the fish is of high interest to both retailers and consumers. Colour grade of the fish flesh is the most important attribute when assessing the quality and price in industry. However, marine species like yellowfin tuna are highly susceptible to rapid spoilage. Therefore, loss of quality of flesh followed by spoilage is a complex combination of microbiological, chemical and physical processes. Therefore, the quality of fish can be estimated by sensory evaluation, microbial method and chemical method (Ozogul and Gokbulut, 2006). This study was designed to evaluate the chemical qualities of yellowfin tuna flesh by measuring histamine, microbiological qualities by measuring total plate count and sensory qualities in four colour grades. Methodology The research was carried out at the Ceylon Fresh Seafood (Pvt) Ltd. Fresh yellowfin tuna flesh colour was categorized into four colour grades such as, bright red, light red, brown red and pale brown using a reference colour chart. Forty fishes were selected from each colour grade making total sample size 160 individual fishes. Homogeneous samples were selected to get accurate results. Therefore, all the samples were collected from Negombo landing site with identical body weight and length and sex. The temperature of each fish was measured and samples were collected only from the fishes which contain body temperature below 4 °C. Appropriate 160 samples of four colour grades were collected from the area below the pectoral fin of each fish. Histamine values were measured by using competitive direct Enzyme Linked Immune Sorbent Assay (CD – ELISA) method (AOAC 977.13 method, 1992). Data were analysed by using one way Analysis of Variance (ANOVA) with 95% confidence interval using Minitab 16 software. Another 160 samples were collected from the area below the pectoral fin of above selected fishes to test the Total Plate Count (TPC) according to the AOAC (1992). Data were analysed by using one way Analysis of Variance (ANOVA) with 95% confidence interval using Minitab 16 statistical software. Organoleptic parameters such as odour, texture, appearance and overall acceptance of four colour grades were evaluated using thirty two untrained penalties. This sensory scale is based on the freshness quality grading system for yellowfin tuna mentioned in Act No. 1045/01 Gazette notification in 1998. Each assessor was given scoring demerit point from one to four. Data were analysed using non - parametric Freidman test in Minitab 16 software.
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    Study on the Effect of Different Levels of Heat on the Quality of Dark muscle of Yellow Fin Tuna Thunnus albacares
    (Uva Wellassa University of Sri Lanka, 2013) Jayasinghe, L.L.S.L.; Wijesundara, W.M.N.M.; Liyanage, N.P.P.; Madage, S.S.K.
    Coastal 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.