Research Symposium-2015
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Browsing Research Symposium-2015 by Author "Abesinghe, A.M.N.L."
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Item Development of Avocado (Persea americana) Incorporated Set Yoghurt(Uva Wellassa University of Sri Lanka, 2015) Kulasinghe, W.M.A.A.; Abesinghe, A.M.N.L.; Gunawardhane, L.K.A.Yoghurt is one of the best known of all cultured-milk products in the world. According to SLS standards (1989) Streptococcus thermophillus and Lactobacillus bulgaricus are used to convert lactose in milk in to lactic acid during yoghurt production. Fruit yoghurt is produce by adding fruits and their nectars, jams, marmalade, fruit jellies, fruit drinks, fruit syrups and concentrated fruit drinks to yoghurt or cultured pasteurized milk and fruit yoghurts enhances versatility of taste, color and texture for the consumer (Chandan and Shahani, 1993). Avocado (Persea americana) is a fruit which is having a very good nutrient profile and thus incorporation endorses the healthy image of yoghurts. However, incorporation of avocado in to set yoghurt is limited by enzymatic browning or formation of brown color melaniodins from polyphenol oxidase enzyme in avocado (Bindesh, 2010). Pauker et al. (1992) have found incorporation of avocado in to yogurt in the form of fresh avocado pulp is impossible due to enzymatic browning. Therefore, control of enzymatic browning is essential in producing avocado incorporated set yoghurt. Current study was carried out to develop avocado incorporated set yoghurt that is having an adjusted solid content based on sensory properties and controlling enzymatic browning of avocado pulp. Methodology Market available fresh ripened avocados (Fuerte variety) were manually peeled and crushed in to a smooth pulp. It was divided in to seven samples with same weight and preserved using several preserving and enzymatic browning control methods such as 1% citric acid, 1% (w/w) ascorbic acid (Patricia et al., 1993), 1% (w/w) citric acid and 1% (w/w) ascorbic acid together (Lopez, 2001), 0.1% (w/w) sodium benzoate (Patricia et al., 1993), 0.1% (w/w) potassium sorbate (Singha, 2011), heat treatment at 40 ºC temperature for 30 minutes (Cantwell, 1992) and preparation of avocado pulp as a jam (Connelly, 2013). The best avocado pulp preserving method (least color changing treatment) was selected by conducting a sensory evaluation using 30 untrained panelists. The selected method of preserving avocado pulp (avocado jam) was used in preparation of avocado incorporated set yoghurt. Yoghurt mix preparation was done according to Pande (2010). Preliminary trials were used to select the appropriate level of ingredients (avocado jam, sugar and gelatin). Sugar and gelatin levels were finalized after having several sensory trials using 30 untrained panelists. Potassium sorbate 0.03% (w/w) was added to the final mixture as preservative (SLS Standards, 1989) and homogenized using a beater (National™, MK-H100N). Inoculation of lactic acid bacteria culture of YC 350 freeze dried (DVS) was done at 45 °C temperature. Then mixture was poured in to 80 mL plastic yoghurt cups and incubated at 42 ±2 ˚C for 4 hours. Each treatment consisted with three replicates. Total plate count, coliform bacteria count, yeast and mold count, pH, titratable acidity and peroxide value of selected avocado incorporated set yoghurt and avocado jam was tested at day under refrigerated storage. A proximate analysis was done to determine the composition of the avocado incorporated set yoghurt. Results and Discussion Addition of 50% (w/w) sugar in to avocado pulp showed lowest brown color development (P<0.05). Added sugar may have reduced the water activity of the avocado pulp. Enzymes require certain level of water in their structures to maintain their natural conformation, allowing them to deliver their full functionality. Therefore, presence of 50% sugar inhibits the activity of polyphenol oxidase enzyme. Adding more than 50% of sugar, crystalize sugar in the avocado pulp which gives undesirable consistency. Twenty percent of avocado jam incorporation level shows the best results according to the sensory evaluation (P<0.05). Total plate count, yeast and mold and coliform counts of the avocado incorporated set yoghurt were not exceeding SLS standards for set yoghurt during 11 days of refrigerated storage. Titratable acid percentage of avocado jam has increased from 1.22±0.07 to 1.4±0.07 during day 1 to day 11 (P<0.05). It may be due to conversion of fermentable sugars in to acids by microorganisms available in avocado jam. Further, titratable acid percentage of avocado incorporated set yoghurt increased from 0.86±0.03 to 0.94±0.03 during 11 days storage period (P<0.05). This is due to the presence of live lactic acid bacteria in culture which ferment lactose in milk to lactic acid with the time (Chandan and Kilara, 2013). pH of avocado jam and pH of avocado incorporated set yoghurt was reduced from 3.52±0.06 to 3.35±0.06 and from 4±0.03 to 3.91±0.03, respectively during day 1 to day11. Increasing acidity results in decreasing pH level in the product. No fatty acid oxidation was detected in the avocado jam during storage period of 11 days. Avocado incorporated set yoghurt started free radicle formation and rancidity development day of storage onwards. Moreover, it shows increasing browning effect. Since, avocado is a fruit with high fat and it contains considerable level of fatty acids, there is a potential to observe oxidation in this product. Statistical analysis showed that enzymatic browning has an influence on the increment of changing rapidity of titratable acidity, pH and peroxide value. Further, it showed fatty acid oxidation and pH are not related. In the view of avocado incorporated set yoghurt and avocado jam, avocado jam is having very low water activity due to saturated sugar solution. Avocado incorporated set yoghurt is having an environment with increasing acidity and decreasing pH with lactic acid fermentation. Water activity of avocado incorporated set yoghurt also very high compared to avocado jam. These factors may have influenced on the observed color change in avocado incorporated set yoghurt. Proximate analysis of avocado incorporated set yoghurt showed that there is a significant difference with plain yoghurt (P<0.05). Fat (3.6±0.42%), fiber (0.3±0.21%), ash (0.9±0.14%), protein (3.5±0.07%) and total solids (16.10±1.31%) in avocado incorporated set yoghurt is comparatively higher than available fat (3.0±0.42%), fiber (00±0.21%), ash (0.7±0.14%), protein (3.4±0.07%) and solids (14.24±1.31%) in plain yoghurt. Conclusion Avocado incorporated set yoghurt is more nutritious compared to set yoghurt as it has included with more protein, minerals and fiber. There is a relationship between enzymatic browning and fatty acid oxidation. Further studies are required to identify how enzymatic browning and fatty acid oxidation relates with each other and to extend the shelf life of avocado incorporated set yoghurt.Item Development of drinking yoghurt by incorporating corn (Zea mays) milk and corn seeds(Uva Wellassa University of Sri Lanka, 2015) Mendis, R.I.W.; Abesinghe, A.M.N.L.; Samaraweera, A.M.; Gunawardhane, L.K.A.Cereal grains are considered as important sources of dietary proteins, carbohydrates, vitamins, minerals and fiber for people all over the world (Chavan and Kadam, 1989). Corn (Zea mays) is locally grown cereal that can be purchased at low price from several areas in Sri Lanka. Corn milk is considered as a new innovation, especially in making yoghurt based products. Vegetable based corn milk yoghurt is an alternative to substitute the cow milk based yoghurt. Drinking yogurt is the fastest growing food and beverage category in worldwide (Yasni and Maulidya, 2013). However, still value added drinking yoghurts are rare in Sri Lankan market. Adding cereal grains is a perfect way to upgrade a drink to a nutritious breakfast. Therefore, this study was conducted to develop yoghurt by incorporating corn (Zea mays) milk and corn seed to cow milk. Methodology The study was carried out at Lucky Lanka Milk Processing Com. Ltd (LLMP), Matara and Uva Wellassa University. Six experimental trials with different treatments were conducted. In trial I, mature fresh corn seeds, mature boiled corn seeds and germinated corn seeds were separately used to extract corn milk and the best extract of corn milk was evaluated by sensory properties (odor, taste, color and mouth feel) using untrained panelist. In trial II the most compatible sugar (8%, 9% and 10% w/v) and gelatin (0%, 0.2% and 0.4% w/v) levels for different corn milk percentages (5%, 10%, 15% and 20% w/v) were identified. After selection of appropriate combinations of sugar and gelatin levels, trial III was done to select the best corn milk incorporation level by narrow downing the corn milk percentages (6%, 8%, 10%, 12% and 14%). Preserved in sugar syrup and boiled corn seeds were crushed into two sizes (> 3.15 mm and 2 mm –3. 15 mm) to prepare different types of corn seeds. Trial IV was carried out to select best corn seeds particles on the textural basis and trial V was done to assess the consumer acceptability for the presence of corn seeds in the corn milk incorporated drinking yoghurt. Finally three treatments (trial VI) were prepared and evaluated on sensory, chemical and microbiological properties. The sensory evaluation was done using 35 untrained panelists. In chemical analysis, proximate analysis (moisture content, crude fat, total solid, crude protein, ash and crude fiber content) was conducted. pH value and titratable acidity were evaluated and microbiological analysis was done for Yeast and Moulds, and Escherichia coli for three weeks in one day interval. The sensory data were analyzed using Friedman nonparametric test. Complete Randomized Design was conducted and data obtained from chemical and microbiological tests were analyzed by Analysis of Variance using the General Linear Model procedure of SAS. Significant means of treatments were separated using the Least Significant Difference test (P< 0.05). Result and Discussion In trial I, boiled corn seeds (mature) based method was selected to extract corn milk. Other two methods were rejected due to the unpleasant odour and taste which may be due to the activation of various food enzymes and breaking down the higher molecular components to simple molecules during germination. Eight per cent sugar (w/v) for 5% corn milk (w/v) and 10% sugar (w/v) for other 10%, 15% and 20% corn milk (w/v) incorporation levels were selected due to desirable sweetness. The gelatin level (w/v) was selected as 0% due to the presence of appropriate drinking yoghurt properties including texture, mouth feel, appearance and viscosity. The whey separation has been prevented by stabilizing effect of corn starch in corn milk. In sensory evaluation, 8% corn milk incorporation level was significantly highly preferred by panelist with respect to mouth feel, taste and overall acceptability (P<0.05). However, there is no significant difference in color and aroma of the three treatments (P>0.05) (Figure 01). Addition of corn milk had no influence to change colour and aroma of the product. Overall acceptabilty 6 4 2 0 Aroma 7% corn milk incorporation level 8% corn milk incorporation level Taste Mouth feel 9% corn milk incorporation level Figure 01. Web diagram for level of corn milk incorporation in sensory evaluation In trial IV, sugar syrup based method was rejected due to hardness of the seeds and crushed boiled corn seeds were selected. Further, the sensory results revealed that the preference (taste, aroma, mouth feel, color and overall acceptability) for corn seeds >3.15 mm or 2 mm to 3.15 mm particles incorporated drinking yoghurt is less whereas preference for corn milk incorporated drinking yoghurt without corn seeds was high. The observed difference is due to the disturbance for the drinkable property of product by presence of corn seed particles. The composition of the selected corn milk incorporated drinking yogurt is given in Table 01. There was a significant difference between treatments for change in pH with the storage period (P<0.05). pH values of the T8 (with preservative) and control were not changed dramatically. Control of pH by potassium sorbate could be due to inhibition of the activity of starter culture by inhibiting various enzymes in microbial cell (Rajapaksha et al., 2013). There was a significant difference between treatments with respect to acidity (P<0.05) and titratable acidity increased significantly with storage period and in treatments without preservatives. According to Rajapaksha et al. (2013), titratable acidity of yogurts increased over the time and acidity of yoghurt without potassium sorbate increases drastically than other treatments reflecting the inhibitory activity of potassium sorbate on post fermentation. Table 01. Composition of select corn milk incorporated drinking yoghurt Raw material Percentage Quantity (g) Milk 79.54% 867.03 Dairy cream 1.03% 11.33 SMP 1.42% 15.49 Corn milk 8.00% 87.20 Sugar 10.00% 109.00 Total 100.00% 1090.00 There were no contaminations with Coliform and Escherichia coli and thus safe for human consumption. There were no yeast colonies in T8 and control sample. At day 11, yeast colonies were exceed the SLS standards of <1000 only in T7 (without preservative). Proximate analysis revealed all the physiochemical characteristics of corn incorporated drinking yogurt (protein, fat, ash, fiber and total solid), except moisture significantly higher compared to plain drinking yoghurt (P<0.05). Usually drinking yoghurt does not contain fiber. However, due to addition of corn, milk fiber was increased up to 0.5%. Conclusion Eight per cent corn milk incorporation level with selected sugar (10%) and gelatin (0%) level has best consumer preference with respect to the taste, mouth feel and overall acceptability (P<0.05). Moreover, drinking yoghurt without corn seed particles is preferred by the panelists. Shelf life of product without potassium sorbate is around 11 days at 4 ºC with respect to microbiological analysis and physiochemical analysis.Item Development of Finger millet (Eleusinecoracana) incorporated symbiotic drinking yoghurt(Uva Wellassa University of Sri Lanka, 2015) Awanthika, H.K.T.; Abesinghe, A.M.N.L.; De Silva, U.Sri Lankan yogurt market is characterized by intense competition prompting leading players to differentiate themselves by focusing on health benefits, branding, and incorporation of different ingredients. Yoghurt is a popular fermented dairy product due to its health benefits as a functional food in addition to its nutritional benefits (Robinson and Tamime, 1999). High calorie yogurt drink that contains any kind of a cereal powder is completely a new product concept to the Sri Lankan market. Therefore, the objective of the current study was to develop a health beneficial probiotic drinking yoghurt by incorporating finger millet as a cereal which can be used as a breakfast food, sport supplement and also as a weaned food for toddlers. Nutritionally, finger millet is used as a whole grain, it is higher in protein and minerals in comparison to all other cereals and millets. Accroding to previous studies, finger millet is also known for several health benefits such as anti-diabetic, antitumerogenic, atherosclerogenic effects, antioxidant and antimicrobial properties which are mainly attributed due to its polyphenol and dietary fiber contents (Dykes and Rooney, 2007; Chethan, 2008). Therefore this study was conducted to develop a cereal based probiotic yoghurt drink which can be promoted as a natural source of high calorie that can be consumed as an alternative for the imported, artificial and expensive sport nutrition’s and weaned foods. Methodology The study was conducted at the research and development and quality assurance laboratories in Ceylon cold stores PLC, Ranala, Kaduwela. In the preliminary trial 1 most compatible sugar percentages for different incorporation levels of finger millet flour from the three experimental forms (roasted flour, germinated flour and raw slurry) were selected. Then preliminary trial 2 was carried out using ranking method to select the best finger millet incorporation levels (4 %, 5 %, 6%, 7% and 8 % (w/w)) for each incorporation form. The best sugar percentages and incorporation levels of finger millet from preliminary trials were used in next steps of experiments. Sensory evaluation 1 was carried out to select the best form/type of finger millet flour to incorporate out of three forms. In second sensory evaluation, the most suitable stage for finger millet incorporation was determined by using two treatments. Each sensory evaluation was conducted with 30 untrained panellists and color, taste, aroma, mouth feel and overall acceptability were considered as sensory properties. Finally proximate analysis, physico- chemical and microbial analysis were conducted for the selected final probiotic drinking yoghurt by comparing with a control sample. Probiotc lactic acid bacteria enumeration was carried out using the selected final product by pour plating on MRS media to find out the effect of finger millet incorporation on the viability of probiotic lactobacilli. Selected final product was compared with a control sample and enumeration was done at 1, 7 and 14 days interval. The sensory data were analyzed using Friedman non-parametric test with 95% significance by using Minitab 16 software. Complete Randomized Design (CRD) was conducted and data obtained from chemical and microbiological tests were analyzed using analysis of variance (ANOVA) using the SAS 9.0 software. Significant means of treatments were separated using the Least Significant Difference test (LSD) (P< 0.05). Results and Discussion According to the results of the series of preliminary trials 5% (w/w) was selected as the best incorporation level from each three finger millet forms and 8 % (w/w) sugar as the compatible sugar percentage. In the first sensory evaluation for selecting best form/type of incorporation out of three experimental forms, germinated /malted flour incorporated yoghurt was selected as the best due to higher preference than other two. There was a significant difference (P<0.05) between treatments regarding and overall acceptability. Second sensory evaluation revealed, 5 % (w/w) germinated (malted) finger millet flour incorporated (Addition before fermentation) drinking yoghurt have the higher preference compared to the other treatmentItem Development of fruit (Musa spp.) puree incorporated synbiotic stirred yoghurt(Uva Wellassa University of Sri Lanka, 2015) Nanayakkara, G.H.; Abesinghe, A.M.N.L.; De Silva, U.Yoghurt is one of the most nutritious fermented milk products that can be used to enhance the nutrition condition of people. It is obtained by introducing specific strains of Lactic acid bacteria. The Lactic acid micro flora reduce risk of colon cancer (Foissy, 1983 cited in Huma, 2003), reduce the serum cholesterol level (Anderson and Gilliland, 1999 cited in Huma, 2003) and also maintain the intestinal ecosystem (Saarela et al., 2002 cited in Huma, 2003). Prebiotics are non-digestible food ingredients that improve the host health by selectively stimulating the growth of certain beneficial microorganisms. Fructo-oligosaccharide is prebiotic source that can be found in ripe banana around 2 mg/g. By incorporating banana with yoghurt is best way to improve the health benefits and taste of the yoghurt. Stirred type fruit yoghurt is one of the best products that can be used to gain consumer preference. Therefore, this study was conducted to develop a Banana puree incorporated symbiotic stirred yogurt. Methodology The current study was carried out at Ceylon Cold Stores PLC (CCS), Ranala, Kaduwela. Laboratory analysis was done at CCS and laboratories in University of Kelaniya. First, yoghurt base and the banana puree were prepared according to the predetermined recipe after various preliminary trials. For final sensory evaluation, three treatments were used with three replicates.Item Development of soursop pulp (Annonamuricata) incorporated fermented sweet cream buttermilk beverage(Uva Wellassa University of Sri Lanka, 2015) Buddhadasa, K.; Abesinghe, A.M.N.L.; Luxman, R.A.J.N.In Sri Lankan context buttermilk removed from the dairy processing plants considered as a dairy waste and utilization of dairy by product is considerably low compared to other countries. Sri Lankan market is still having a market gap for locally produce fermented flavored milk base beverages. Buttermilk could be used to produce fermented milk beverages replacing milk which would result in differentiated products. Buttermilk is also considered a nutritious dairy ingredient that is saturated in milk fat globule membrane (MFGM) components (Sodini et al., 2006). Addition of fruit juices or pulps is an attractive avenue for the utilization of buttermilk. Soursop is one of the fruit spp. which can be incorporated to manufacture beverages with good consumer demand. The fruit is rich in vitamin B, potassium, fructose and vitamin C (Pamplona-Roger, 2005 cited in Ekaluo et al., 2013). Soursop fruit is a proven cancer remedy for cancers of all types and broad spectrum antimicrobial agent for both bacterial and fungal infections, antiparasitic activity, lower high blood pressure and is used for depression and stress (Camiel et al., 2008). Methodology The current study was carried out at Pelwatte Dairy Industries Limited, Pelwette and laboratory analysis was done at Pelwatte Dairy Indusries Limited and Uva Wellassa University laboratories. Soursop pulp was prepared by flowing method. Fresh fully ripped Soursop fruit was washed by chlorinated water and disinfected by using 70% of ethanol. Then fruit was cut it to halves by using a sharp knife and seeds and blemishes were removed. After that, flesh was scooped out using a clean stainless steel spoon and blended it using an electric blender. Initially incubation time was standardized for the buttermilk base by incorporating different levels of Skim Milk Powder. Several preliminary studies were done to select the best Soursop pulp and Sugar incorporation level for the final product. Sensory evaluation was done using 30 untrained panelists for the final three treatments (12%, 13% and 14% of Soursop). The pH value and acidity were evaluated in one day intervals for thirteen days in both Potassium Sorbate added sample and without preservative sample and microbiological analysis was done for Escherichia coli, Coliform and Yeast and Molds. The sensory data was analyzed using non- parametric procedure, according to the Friedman test with 0.05 levels of significance in Minitab 16 software package. Complete Randomized Design (CRD) was conducted and data obtained from chemical and microbiological testes were analyzed using analysis of variance (ANOVA) using the General Linear Model (GLM) procedure of SAS software. Results and Discussion Skim Milk Powder was added to buttermilk to increase the total solid content. The increase of total solid content has reduced the incubation time by influencing the growth and activity of starter culture (Figure 01). Incubation time was reduced to 4 hours by adjusting Skim Milk Powder level to 6 grams/100 mL. Eight grams of Skim Milk Powder addition level was not selected as it can increase the cost of production.Item Effect of different aerobic and anoxic time periods on the effluent water quality of a sequence batch reactor in a meat processing plant(Uva Wellassa University of Sri Lanka, 2015) Kahandawa, K.P.W.; Abesinghe, A.M.N.L.; Samaraweera, A.M.; Dissanayake, J.K.product manufacturing. It contains high concentrations of organic matter, oil and grease and nitrogenous compounds. Hence, releasing waste water to the environment causes many environmental problems such as contamination of groundwater and eutrophication of surface waters (Rodriguez et al., 2010). The treatment of waste water is especially important in this view. Treatment of wastewater by means of biological process has been widely implemented from urban to industrial wastewater. Sequencing batch reactor (SBR) is a modification of activated sludge process and operates by a cycle of periods consisting of fill, react (alternatively aerobic and anoxic periods), settle, decant, and idle (Mahvi, 2008). In the SBR process there is no standard time combination for aerobic and anoxic period. It will depend on the effluent waste water components and vary plant to plant. Currently aerobic and anoxic period is operated as 2 hr aerobic and 1 hour anoxic period in the waste water treatment plant of CIC meat processing company. The present investigation was undertaken to study best time combination of aerobic and anoxic time period for simultaneous carbon oxidation, nitrification and denitrification performance of sequencing batch reactor to treat slaughterhouse wastewater. Methodology The current study was carried out at CIC Poultry Farms Pvt Ltd (Processing Plant), Badalgama. Laboratory analysis was done at CIC Processing Plant Laboratory and Uva Wellassa University laboratories. Model structure of aeration tank which has the capacity of 600 L was used to conduct the research experiments. 180 mL of sludge from SBR unit in CIC meat processing plant and 420 mL volume of wastewater was fed to tank each day of the treatment. Air was supplied to the reactor during aerobic phase of react period with the help of diffused aeration system and Anoxic conditions were maintained by switching off the aerators. Eight different combinations of aerobic and anoxic periods were used. Every sequence was operated totally for 20 hrs of react period by alternating the aerobic and anoxic period according to selected different time combinations (Table 01). Table 01: Selected time Combinations for Aerobic and Anoxic time periods Control T1 T2 T3 T4 T5 T6 T7 T8 Aerobic (Hours) 2 2 3 3 4 4 4 4 Anoxic (Hours) 1 2 1 2 1 2 3 4 The best combination of aerobic and anoxic time period was determined by analyzing water quality parameters as, COD, BOD, ammonium nitrogen, total nitrogen, TSS, TDS and pH. Complete Randomized Design (CRD) was conducted and data obtained from chemical and physical tests were analyzed using analysis of variance (ANOVA) using the General Linear Model (GLM) procedure of SAS (SAS Institute Inc., 2000). Significant means of treatments were separated using the Least Significant Difference (P< 0.05) test. Results and Discussion There was a significant difference (P<0.05) between aerobic and anoxic time combinations regarding COD removal, BOD removal, TN removal and ammonium nitrogen removal. 4 hour aerobic and 2 hour anoxic period showed higher COD removal (95%), BOD removal (90%), TN removal (89%), and ammonium nitrogen removal (92%). There was no significant difference (P>0.05) regarding phosphorus removal, TSS removal and TDS removal among different aerobic and anoxic time combinations. Highest COD and BOD removal occurred in 4 hour aerobic and 2 hour anoxic cycle. Second highest COD removal (92%) was achieved during 4-1 react period. This might be due to during 4-2 hr and 4-1 sequence total aerobic react time is higher than other react cycles. Therefore, longer aeration was achieved. Longer aeration period has been found to be effective in achieving higher degree of nitrification and COD, BOD removal according to the findings of Debsarkar et al. (2006). Due to less total aeration time in 4-3 and 4-4 hr cycles, less COD and BOD removal was achieved. That means one cycle was alternatively operated for 20 hrs totally and in the 4-3 and 4-4 cycles has high anoxic time periods. Therefore, less COD and BOD removal occurred (Kundu et al., 2013). Treatment 6 (4-2) is significantly different from other treatments and also treatment 5 has high BOD removal. This may be due to long aeration time and effective denitrification. According to Kishida et al. (2003), BOD concentration of the effluent was relatively high because the oxygen demand by nitrifying bacteria increased the total BOD, when the NH,-N concentration of the effluent was too high (average = 187.1 mg/L). NH,-N concentration of the effluent was high due to partial denitrification. According to this experiment ammonium nitrogen concentration also affect to the BOD removal. And treatment 6 had low level of ammonium nitrogen concentration in effluent water (1.048 mg/L 1.07 mg/L). Longer aeration period (5 hour) has been found to be effective in achieving higher degree of nitrification from Debsarkar et al. (2006). But according to preliminary study at the middle of hour pH is reached to 6.9, but optimum pH for nitrification is 8.2. Therefore, in this experiment longest aeration time per one cycle was selected as 4 hr. According to the statistical analysis, there is no significant difference (P> 0.05) between different aerobic, anoxic time combinations and total dissolved solid and total suspended solids removal. This might be due to activated sludge treatment is not intended to remove dissolved or suspended solids (Sustarsic, 2009). Conclusions The combination of 4 hours aerobic react period and 2 hours anoxic react period has been found to be optimum from the view point of both nitrification and denitrification, and COD, BOD removal. When total aeration time period is low, removal of COD, BOD is not efficient in 4 hr aerobic – 4 hr anoxic and 4 hr aerobic – 3 hr anoxic time combinations.Item A Study on Crocodile Behavior (Crocodylus palustris) and Public Value Orientation in Ethimale of Monaragala District(Uva Wellassa University of Sri Lanka, 2015) Wijethilaka, W.G.R.I.; Samaraweera, A.M.; Abesinghe, A.M.N.L.Mugger crocodile (Crocodylus palustris) is principally restricted to Indian subcontinent and the highest number is recorded in Sri Lanka (Da Silva and Lenin, 2010). Crocodylus palustris is categorized as a vulnerable species in IUCN red list (2011). Furthermore, due to destruction of their natural habitats, illegal hunting, fishing activities and crocodile attacks during sand mining, bathing and washing, there is an emergence of this interaction as a human-crocodile conflict. Though the existence of considerable number of C. palustris is recorded in Uva less literature is available on their status in Uva Province of Sri Lanka. Therefore, this study was conducted to understand people’s attitudes, risks, believes and practices towards human crocodile conflict and to study the behavior of crocodile in Ethimale area. Methodology The study was conducted in villages surrounding eight perennial and seasonal tanks (Doser tank, Wattarama tank, Kotiyagala tank, Heekaduwa tank 1 and 2, Karadandara tank, Karakolagaswewa tank and Vila oya) at Ethimale of Monaragala district from May to August 2014. Ninety four individuals were interviewed using a pre-tested structured questionnaire including farmers, fishermen and villagers to determine their awareness, knowledge, practices, believes and attitudes regarding C. palustris. The information on purpose, frequency and duration of water body usage by the villages, crocodile population, their approximate size, migration and their availability throughout the year in the area was gathered through the questionnaire. Moreover, the practices of the people and attitudes regarding crocodiles were identified by gathering information on crocodile attacks, financial damages, people’s reaction when seen crocodiles, offending actions, benefits/uses of crocodiles and threats face by crocodiles. Presence of fecal pellets, footprints, smashed vegetation and cleared basking areas were observed to study the migration and basking behavior. Data analysis was carried out by Microsoft Excel and map was created using ArcGIS software including crocodile migration paths. Results and Discussion Awareness of the people The main water sources of Ethimale were tanks and Vila oya. Therefore, around 97% of the respondents used tanks for their needs daily. Moreover, most of households are by or close to the tanks which explains their close relation with the crocodiles. Knowledge of the people regarding crocodiles Sixty eight percent of the respondents considered that crocodiles were useful and 32% of respondents believed that crocodiles were not useful or did not know the ecological roles played by the crocodiles. According to them, consumption of crocodile meat and egg are the major uses. Around 53% of the respondents have eaten crocodile meat while 5.3% have consumed crocodile eggs. Though few had heard the uses of crocodile hide they have not done any hide processing. Though the respondents have seen crocodiles throughout the day, crocodiles were common on tank sides especially in the morning (6.00 to 8.00 a.m.) and evening (5.30 to 7.00 p.m.). Based on the observations of the respondents, highest crocodile number was reported from Kotiyagala tank (20 to 25), followed by Heekaduwa tank-1 (15 to 20) and Heekaduwa tank-2 (10 to 15). Regarding the approximate length of the largest crocodile seen by the respondents, majority (62%) of has seen largest crocodile in between 2-3 m in length. Nesting season, i.e., from June to August of Crocodylus palustris coincides with the dry season in Monaragala (June to September) (Department of meteorology statistics, 2014). Therefore, the hatching of eggs takes place with the beginning of the rainy season. Around 45% of the respondents have seen crocodile nesting sites at tank bunds, Vila oya sides, canal sides, Vila oya anicut and jungle area which close to tanks.However, 11% of respondents have seen Water Monitors (Varanus salvator) and Land Monitor (Varanus bengalensis) as main predators of crocodile eggs. Among the crocodile deaths observed by the respondents, most of the recorded crocodile deaths were due to human actions such as shooting and hitting when the crocodiles attack to the fishing nets (Specially for hatchlings). Two crocodile attacks to the fishermen while fishing were reported. However, 37% of the respondents have faced some financial damages from the crocodiles as damage to livestock (especially to calves) (37%), loss of fish yield (29%), fish net damage and damage to pet animals. Among them damage to livestock and damage to net and loss of fish yield were common. Moreover, threat from crocodiles was reported as one reason to refrain youngsters from fishery. Attitudes regarding crocodiles Though 77% of the respondents have agreed that the crocodiles have become threat to fishery or daily uses of the water body, 73% of the respondents still believe that conservation programs for crocodiles are essential, since they believe that the number of crocodiles are depleting annually. Moreover, they have suggested translocation of crocodiles (to large tanks, national parks and zoo) and ecotourism to minimize the human crocodile conflict may be due to the ethical reasons since all the respondents are Buddhists. Crocodile migration and basking behavior Crocodiles were migrated during the dry season and they were returned to their original habitats at the beginning of the rainy season. Therefore, crocodile migration was highest during August where all most all the seasonal tanks were dried and low water level was observed in perennial tanks. With the beginning of rainy season in September, crocodiles were returned to their original habitats. Crocodiles were basked commonly during 6.00 am to 9.30 am under direct sun light (average 33°C daily temperature) in open areas such as dead trees in water, on the Vila oya river bank, tank sides/bund and surrounding rocks. With the high day time temperature, they were moved to the tank bottom and come to the top only for breathing meanwhile some crocodiles were moved to burrows. Recommendations to solve human crocodile conflict and conservation To minimize human-crocodile conflict conducting awareness program to villagers including conservation and laws related, installation and maintenance of crocodile excluding areas at bathing places, installing warning sign boards and translocation of crocodiles which trap to fish nets can be done. The crocodile conservation can be done to some extent by sharing conservation and management responsibility among local community. The crocodiles can be an attraction of visitors and create employment opportunities for the local community. Eco- tourism may be a good solution for involving people with their traditional knowledge about crocodile conservation and will be helpful to uplift the local socio-economic conditions. Other than eco-tourism, protection of nesting habitats, initiation of crocodile parks or sanctuary, conservation education and public awareness also can be practiced. Conclusion Majority of the villagers have sound knowledge regarding crocodile population, behavior, migration patterns and availability. Since almost all the people were engaged with the tanks for their daily needs and majority was farmers and fishermen. Though there are several livestock attacks and economic losses from crocodiles no fatal attacks recorded to people. Therefore, majority of the people in Ethimale was having a positive attitudes regarding conservation of crocodiles.