Browsing by Author "Amarakoon, A.M.T."

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Bio-Chemical Evaluation of Selected Sri Lankan Tea (Camellia sinensis L.) Cultivars and Accessions for Production of Green Tea
(Faculty of Graduate Studies, University of Kelaniya, 2015) Ranasinghe, H.P.P.; Rajathewa, R.M.A.S.N.; Kottawa-Arachchi, J.D.; Ranathunga, M.A.B.; Amarakoon, A.M.T.
Two major types of tea, ―green tea‖ and ―black tea‖ are produced from the young shoots of Camellia sinensis L. employing different processing methods. Sri Lanka traditionally produces black tea and the existing cultivars are more suitable for black tea production. However, due to the increased demand for green tea in certain countries, it could be economically advantageous for some Sri Lankan factories to produce green tea for niche markets. Therefore, this study was conducted to evaluate the potential of using selected Sri Lankan tea cultivars and accessions for the production of green tea. Tender shoots (two leaves and the bud) from 35 cultivars/accessions from St. Coombs Estate, Tea Research Institute of Sri Lanka, Talawakelle were steamed and dried to obtain green tea samples. Total polyphenol, catechin, free amino acid and caffeine content were determined by UV-vis spectrophotometric methods. Crude fiber content was determined according to ISO 5498. Three Chinese green tea samples were used as the controls. Crude fiber content was found to be < 16.5 %. Total polyphenol and catechin were found to be in the range of 9.55-26.19 % and 7.91-20.07 % respectively, while free amino acids and caffeine were found in the range of 0.83-5.31 % and 3.98-7.60 % respectively. According to the correlation matrix of different bio-chemical parameters, positive correlation was identified between catechin and total polyphenol content. Besides total polyphenol content had a significant negative correlation with amino acid content. Principal Component Analysis (PCA) revealed that, total polyphenols, amino acids and catechins are the main contributing characters. Based on the first three PCs, analyzed tea samples clustered into three main groups at an average distance of about 1.00. The group I comprised of fourteen cultivars/accessions. Eight cultivars/accessions were included in group II whereas group three represented sixteen cultivars/accessions. Comparatively high amino acid content (1.72- 5.06%), low total polyphenol (9.55-18.30%) and caffeine (4.08-5.80%) of cultivars/accessions in group II (CY 9, TRI 62/5, WHMOR, TRI 4079, PLLG 2 and DN) warrants them to be considered as potential cultivars/accessions for green tea production.
Correlation between selected morphological and biochemical parameters in a hybrid tea population with the blister blight disease
(Research Symposium on Pure and Applied Sciences, 2018 Faculty of Science, University of Kelaniya, Sri Lanka, 2018) Weerasooriya, C.R.; Kottawaarachchi, J.D.; Ranathunga, M.A.B.; Amarakoon, A.M.T.
Tea is produced from the plant species Camellia sinensis. Blister blight is a major leaf disease caused by the fungus Exobasidium vexans in tea resulting in significant yield losses, debilitation and death of tea bushes . Copper and systemic fungicides are currently used to control the disease resulting in high costs and potential residues in tea. In addition, there is a possibility of developing fungi resistance in tea plants to fungicides. Therefore, developing cultivars with resistance towards Blister blight is considered as the most suitable approach to control the disease. In the present study, the correlation between morphological and biochemical parameters was investigated with Blister blight disease with an aim to develop resistant cultivars. Twenty (20) tea samples including 18 accessions produced by crossing two parent cultivars: TRI 2043 (highly resistant to Blister blight) and TRI 3055 (highly susceptible to Blister blight) and the two parent cultivar samples were used in this study. The morphological analysis was carried out with reference to the guidelines given in the descriptors for tea by the International Plant Genetic Resources Institute (IPGRI) in 1997 and the descriptor list of the International Union for the Protection of New Varieties of Plants (UPOV) for tea (2008). Biochemical parameters were analysed following spectrophotometric methods and HPLC methods. Total anthocyanin, caffeine, polyphenol, gallic acid, epigallocatechin, catechin, epicatechin, epigallocatechin gallate and epicatechin gallate contents were determined. Results obtained for morphological and biochemical parameters were statistically analysed using the Minitab software under two categories; calculating the correlation between morphological and biochemical parameters and plotting a dendrogram for morphological and biochemical parameters separately. The Pearson correlation method was used to calculate the correlation between parameters. From the morphological parameters, a positive relationship was observed in the number of average pubescence on young leaf with the Blister blight resistance. Total anthocyanin content showed a positive relationship and epicatechin showed a low negative relationship with the Blister blight resistance. Accession 26 showed a very high total anthocyanin content (0.123 ± 0.065%), a moderate epicatechin content (0.792 ± 0.168%) and a high resistance to Blister blight disease, indicating its potential to be developed as a resistant cultivar. The experiment was duplicated, and the same results were obtained both times. Based on the results, it can be concluded that anthocyanin content can be suggested as a biochemical marker in tea crop improvement programs.
Determination of selected major nutrients in commercially available dairy products in Sri Lanka
(Book of Abstracts, Annual Research Symposium 2014, 2014) Rathnayake, R.A.C.; Amarakoon, A.M.T.
Dairy products are available in the Sri Lankan market in different forms such as powdered milk, packaged liquid milk, yoghurt, ice cream, cheese and butter. Quality standards had been specified for most dairy products by the Sri Lanka Standards Institute (SLSI) while some milk products such as packaged liquid milk and milk containing products such as flavored drinks do not have Sri Lankan standards (SLS). However, published data on the major nutrient content of Sri Lankan dairy products is very limited. Therefore, the aim of this study was to determine the major nutrient contents in the dairy products available in Sri Lanka to find their compliance with the SLS.
Effect of oral administration of hot water infusion of black tea (Camellia sinensis L) on serum toxic heavy metal concentrations in rats
(Institute of Biology, Sri Lanka, 2011) Abeywickrama, K.R.W.; Amarakoon, A.M.T.; Rathnasooriya, W.D.
Method development for the determination of MCPA (4-Chloro-2-methylphenoxy acetic acid) residues in black tea
(Sri Lanka Association for the Advancement of Science, 2013) Amarakoon, A.M.T.; Herath, K.N.S.; Punyasiri, P.A.N.; Abewickrama, K.R.W.
A pilot study on quality parameters of commercially available black tea in Sri Lanka
(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Amamadhu, N. G. L. H. E.; Amarakoon, A.M.T.
Tea is the most popular, widely consumed beverage next to water in the world. Tea is vital for the Sri Lankan economy as a main source of foreign exchange earnings and employment provider. ‘Ceylon Tea’ is considered the best quality tea in the world market. It is important to ensure maintenance of the high quality to sustain the reputation of ‘Ceylon Tea’. Although adequate quality assurance measures are in place for tea exported, less attention is given to the tea in the local market. Therefore, this study was carried out to find the quality aspects of black tea available in the Sri Lankan market. Most popular branded tea samples available in the local market were selected through a survey while loose tea samples were randomly selected. To evaluate the quality of tea samples, the parameters of total ash, water-soluble ash, acid-insoluble ash, alkalinity of water-soluble ash, crude fibre and total polyphenol content were determined based on the methods recommended in the international standard ISO 3720:2011 – Black tea – Definition and basic requirements. In addition, antioxidant activity and total flavonoid content (TFC) were evaluated by DPPH (2,2-Diphenyl-l-picrylhydrazyl) assay and aluminium chloride colorimetric assay respectively. According to the results, percent mass fraction of total ash, water-soluble ash, acidinsoluble ash, alkalinity of water-soluble ash, crude fibre and total polyphenol content of tea samples varied in the ranges between 5.21% - 6.95%, 57.60% - 69.35%, 0.004% - 1.365%, 1.85% - 2.28%, 10.78% -18.95%, and 23.29% -44.76% respectively. The antioxidant activity/ IC50 value of tea samples varied in the range of 32.91 - 49.06 µg/mL and the TFC of tea samples varied in the range of 399.82 - 659.12 µg/mL. Overall, with the limited number of samples tested, all branded tea samples satisfied the requirements of ISO parameters but two loose tea samples deviated from ISO requirements. In one sample acid insoluble ash was 1.37% and in another sample crude fiber content was 18.95%. Both were higher than the minimum ISO requirement. Results of the study indicate that analyzed branded tea meets the ISO quality requirements while some loose tea samples did not meet the quality requirements. Antioxidant activity and the total flavonoid content of branded and loose tea samples were almost similar. More stringent testing of tea in the local market, paying special attention to loose tea, is recommended to ensure the maintenance of high quality and the image of Ceylon tea.
Preliminary study on identification of region of production of Ceylon Tea using concentration of selected elements
(Faculty of Science, University of Kelaniya, Sri Lanka, 2016) de Silva, N.I.U.; Madhusha, R.K.D.; Waduge, V.A.; Mewan, K.M.; Amarakoon, A.M.T.
Sri Lanka is one of the world's leading tea exporters and Ceylon Tea is acclaimed as the best tea in the world due to its unique flavor characteristics. Flavor characteristics of tea are mainly influenced by the variety of tea, climatic conditions and processing methods. Tea is grown in several geographical regions in Sri Lanka and tea produced in those regions acquire distinct flavor characteristics specific to the region. Due to the distinct flavor characteristics, Ceylon Tea fetches higher prices in the international markets than tea produced in other countries. Often Ceylon Tea is blended with tea from other origins and sold as Pure Ceylon Tea to obtain higher prices. In addition, tea produced in particular regions in Sri Lanka are blended with tea produced in other regions of Sri Lanka (e.g. Dimbulla and Uva) which are much sought after teas of Sri Lankan origin. At present, organoleptic assessments are used to identify such adulterations, which could be challenged in courts and arbitration panels. Although not essential, identification of chemical parameters specific to the region of production would facilitate obtaining geographical indications (GI) for tea produced in certain regions such as Dimbulla and Uva in Sri Lanka. Therefore, chemical parameters to distinguish Ceylon Tea from other origin teas and to identify the region of production in Sri Lanka would be invaluable for the marketing of Ceylon Tea. A combination of trace metal content and isotopic ratios of Nitrogen (N), Carbon (C) and oxygen (O) are often used to identify the geographical region of production. Therefore, content of selected metals in tea produced in five regions (Low country, Mid country, Udapussellewa, Up country and Uva) of Sri Lanka was measured as a preliminary investigation to find any relationship with the region of production. Potassium, calcium, manganese, iron, copper, zinc, rubidium, strontium and bromine content of fifteen tea samples representing the five regions were measured using Xray Fluorescence Spectroscopy (XRF) technique. The results obtained, in the present study indicated that there is a direct correlation between the rubidium content of tea and the region of production. Mean Rb content of tea in the five production regions (mg kg-1) were 45.43 (Low country), 39.31 (Mid country), 36.89 (Udapussellewa), 30.98 (Up country) and 20.29 (Uva) on dry weight basis. Tea produced in lower elevations had high Rb content and the Rb content of tea decreased with the increase in elevation. The differences of Rb content in tea could be due to the differences in Rb content in soils in these regions. Results obtained for concentrations of other elements did not indicate any relationship with the region of production. Results of this study indicate that Rb content could be used as one of the parameters for the identification of region of production in Ceylon Tea. Further studies using larger number of tea samples from each region along with soil samples from those regions is required for confirmation of the conclusion.
A preliminary study on selected metals in processed tea samples produced in different regions of Sri Lanka
(Faculty of Science, University of Kelaniya, Sri Lanka, 2020) Gunathilaka, G.A.H.H.; Amarakoon, A.M.T.
Sri Lanka is one of the oldest and most renowned tea exporters in the world. There are three major geographical zones (Up, Mid and Low country) and seven sub agro-ecological regions where tea is cultivated in Sri Lanka. The cultivation and processing have unique features in each region. Therefore, tea produced in specific regions in Sri Lanka acquires unique flavor characteristics and attracts higher prices in the international markets than tea produced in other countries. Often ‘Ceylon tea’ is blended with tea from other origins and sold as ‘Pure Ceylon tea’ to exploit this advantage. The objective of this study was to identify chemical parameters specific to the region of production to obtain geographical indications (GI) for tea produced in different regions of Sri Lanka. Generally, a combination of chemical parameters is used to establish GI. In this study, the focus was on the variation of selected metal contents in tea produced in different regions. The selected metals were Zn, Cu, Pb, Fe, Cr, Na, K and Ca. Tea samples from six agro-ecological regions were collected for the study. Microwave digestion was used as a rapid and efficient method for sample decomposition and the determination of metals was done by Flame Atomic Absorption Spectrometry and Flame Photometry. Results of the statistical analysis using one-way ANOVA indicated that there were significant differences in the mean levels of selected metals in tea among different regions of production. This may be due to the use of fertilizers which contain these metals and differences in soil metal composition in different regions. Machinery contamination may also have a minor contribution. Dendrogram obtained in cluster analysis shows that variation in mean values of metal contents can be clustered into three groups according to the similarity levels. One group is Dimbula and Uva. This might be of significance because they are highly sought-after teas of Sri Lankan origin. Results from the study indicated that variation of metal contents could be used as one parameter to distinguish highly sought-after tea of Dimbula and Uva regions from other regions after establishing the baseline levels for the regions.
Variation of catechin and caffeine content in exotic collection of tea [Camellia sinensis (L.) O. Kuntze] in Sri Lanka and potential implication in breeding cultivars with enhanced quality and medicinal properties
(Food Chemistry Advances, 2022) Kottawa-Arachchi, J. D.; Ranatunga, M.A.B.; Amarakoon, A.M.T.; Gunasekare, M.T.K.; Attanayake, R.N.; Sharma, R.K.; Chaudhary, H.K.; Sood, V.K.; Katoch, R.; Banyal, D.K.; Piyasena, K.G.M.P.; Edirisinghe, E.N.U.
Tea leaves are rich in diverse metabolites with medicinal importance. The quality of made tea is largely depended on the qualitative and quantitative attributes of key metabolites. The aim of the present study was to quantify flavan-3-ols and caffeine of exotic tea germplam and explore the medicinal properties. Fresh leaf flavan-3-ols; catechin, epicatechin (EC), epicatechin gallate (ECg), epigallocatechin (EGC) and epigallocatechin gallate (EGCg), caffeine and gallic acid of 131 accessions (87 exotic and 44 improved cultivars) were performed by High Performance Liquid Chromatography. Variations in metabolites among cultivars as well as between seasons were determined. Among the flavan-3-ols, EGCg was the most abundant followed by EGC, ECg and EC. Hierarchical clustering of 131 accessions based on metabolite diversity resulted two major clusters. Indian introductions clustered with well-known high quality cultivars indicating the potential utilization of high quality black tea production. Exotic accessions with low caffeine contents (< 20 mg g−1) were grouped separate cluster indicating the promising genetic resources for the development of low caffeine tea. Present study revealed that selected exotic tea accessions rich in bioactive compounds such as catechins and caffeine content could be utilized in producing speciality teas with enhanced quality and medicinal properties.