Browsing by Author "De Silva, P.D.P.M."

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    Development of Rapid Dye Reduction (Resazurin) Test for Determination of Microbiological Quality of Coconut (Cocos nucifera) Water
    (Uva Wellassa University of Sri Lanka, 2019) Rangala, R.D.A.; Ranpatabendi, T.; Perera, G.A.A.R.; De Silva, P.D.P.M.
    Traditional microbiological testing methods are labor-intensive and time-consuming. Rapid microbiological tests are very important in manufacturing establishments where quick decisions are required to be taken. Resazurin test is widely used as a rapid and easy method of determining the microbiological quality of milk. The aim of this study was to investigate the applicability of resazurin dye reduction test as a rapid test method to determine the microbiological quality of coconut (Cocos nucifera) water in a coconut water bottling plants. Fifty-five coconut water samples obtained from desiccated coconut mills were subjected to dye reduction test along with the total colony count by standard pour plate method. Samples represented microbial counts ranged from 5.8×105 to 2.65×107 CFU/mL and reduction times range from 3 min to 115 min. A correlation was established between resazurin dye reduction times (min) and the colony forming units per milliliter of coconut water samples. A strong correlation (-0.989) between variables was detected. Regression equation established between dye reduction time and total colony count was applied to predict the microbial quality of coconut water samples. A specific colour chart was developed by using standard colour codes to identify the initial colour and the end colour of the resazurin reduction test. Thus, it can be concluded that the resazurin rapid dye reduction test can be used to identify microbial quality of coconut water within shorter period of time.
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    Effect of Dryer Conditions on Quality of Cinnamon (Cinnamomum zeylanicum Blume) Quills Before Packaging
    (Uva Wellassa University of Sri Lanka, 2019) Abeysinghe, M.G.D.; Wijeweera, A.A.; De Silva, P.D.P.M.; Alakolanga, A.G.A.W.
    Cinnamon is one of the major spices important in export economy. Improper drying of the cinnamon quills may cause to microbial and insect infestations on packed cinnamon quills and it causes quality deterioration of final product. This study was conducted to identify most suitable dryer condition to maintain the export quality of the cinnamon quills before packaging. The prepared cinnamon quills were dried at different temperatures (35, 40, 45 and 50ºC) for different time periods (2, 3, 4, 5 and 6 hours) in dryer. The experiment was conducted as triplicate using 21 treatments with control (shade dried under room temperature, 24 hours). Moisture percentage (Dean and Stark method), oil yield (Clevenger arm method), water activity, microbial count (CFU), pest count per 100 g, cinnamaldehyde content (GCMS) and color (Munsell colour chart) of the cinnamon quills were measured before and after drying. Mean values of moisture contents under different treatments were less than 15% (Standard value).Mean values of oil contents under (35, 40 and 45ºC ) and (2, 3, and 4 hours) were greater than 1% but values (P > 0.05).Water activity of all treatments were less than 0.75 and 35ºC, 2 hours treatment was significantly differed from all other treatments except 35ºC, 3 hours (P < 0.05).Treatments under 35ºC, 3 hours and 35ºC, 2 hours conditions were resulted microbial growth but other treatments were not (P < 0.05). Zero pest count was in sample dried at 35ºC for 6 hours and temperatures higher than 35 ºC (P < 0.05). Mean values of cinnamaldehyde content were greater than 50% in all treatments. Colour did not vary changed significantly among different treatments. Temperature in between 40 – 45ºC for 2, 3, 4 hours were not adversely affected to the quality of cinnamon quills based on oil content, insect count and microbial count. Considering high oil content, microbial and pest count it can conclude that 40ºC, 3 hours is the optimum dryer condition to keep the export quality.