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

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Assessment of selected biochemical parameters in a hybrid population of tea to predict the quality of processed tea
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Abeysekara, R. M. U. N.; Kottawa-Arachchi, J. D.; Ranathunga, M. A. B.; Amarakoon, A. M. T.
Tea is made from the processed leaves of the mature tea plant, Camellia sinensis L. It is one of the most popular beverages in the world. Tea breeding programs constantly attempt to improve the yield and quality of tea by producing new cultivars. Biochemical and molecular markers are frequently used to assist the conventional tea breeding techniques. Chlorophyll a, b, total chlorophyll, carotenoids and total polyphenol content in tea leaves can be used as biochemical markers to predict the quality of processed tea. In this study, young shoots of 112 individuals from a hybrid progeny which was derived from TRI 2043 and TRI 3055 through controlled hybridization in Tea Research Institute of Sri Lanka were analyzed for chlorophyll a, b, total chlorophyll and carotenoid content. 102 individuals from the hybrid population were analyzed for total polyphenol content. Acetone (80%) extraction was used for the analysis of pigments and methanol (70%) extraction was used for the analysis of total polyphenol. Spectrophotometry (absorbance at 470 nm, 646 nm, 663 nm and 765 nm for chlorophyll a, b, carotenoids and total polyphenol respectively) was used with relevant standards for quantification. Statistical analysis (Minitab16 to determine frequency distributions using histograms and boxplots, SAS 9.1 to prepare dendrogram in cluster analysis) of the results had shown wide segregation of the measured parameters and some of the off springs had recorded higher values than the parents. According to the results, highest chlorophyll a content were recorded in accessions 134, 16 and 67 (3.25 mg/g, 3.10 mg/g and 2.92 mg/g respectively) and chlorophyll b in accessions 134, 16 and 67 were also higher than the others in the population (1.21 mg/g, 1.13 mg/g and 1.02 mg/g respectively). The total chlorophyll content in accessions 134, 16 and 67 were recorded as 4.46 mg/g, 4.23 mg/g and 3.95 mg/g respectively. Carotenoid content in accessions 77, 98 and 36 were higher than the others in the population (2.46 mg/g, 1.63 mg/g and 1.10 mg/g respectively). The highest total polyphenol content (33.13%) was recorded in parent TRI 3055. Total polyphenol contents in accessions 94, 72, 95, 92 and 102 were higher than the rest of the progeny (32.51%, 31.33%, 31.10%, 30.87% and 30.28%). Measured parameters of the hybrid population were subjected to cluster analysis. The resultant dendrogram clearly categorized the progeny into four clusters. Accessions with higher chlorophyll, carotenoid and polyphenol contents (accessions 150, 52, 35,134 and 16) could be candidates for the development of new cultivars with better quality tea
Identification of geographical origin using selected elements in tea produced in different tea regions of Sri Lanka
(Faculty of Science, University of Kelaniya Sri Lanka, 2022) Alwis, M. D. N.; Amarakoon, A. M. T.
Tea, derived from the leaves and buds of the shrub Camellia sinensis, is one of the world's most popular beverages owing to its unique flavour, aroma, and therapeutic properties. Due to the tendency for heavy metal accumulation in the plant, processed tea needs to be analyzed frequently to ensure its adherence to maximum limits in international standards. However, recent data is not available on the metal content in Ceylon tea. Ceylon Tea grown in certain geographical areas in Sri Lanka has also gained great popularity in the global tea market mainly due to its unique taste characteristics. As a result, identifying the geographical region of production for Ceylon tea is important to ensure its authenticity as well. Therefore, this preliminary investigation aimed to determine the content of twenty-seven elements and build a simple model that could be used to distinguish the geographical origin of Ceylon tea using processed tea leaves. Four samples each were selected from factories in all seven tea growing regions of Sri Lanka except from Nuwaraeliya (3 samples) and Kandy (2 samples) and analyzed using Microwave digestion and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). Statistical evaluation was conducted with a one-way analysis of variance (ANOVA), Pearson’s correlation, and cluster analysis with a dendrogram using Minitab 19 software package. A relatively high number of elements; Be, U, Ag, Ga, Tl, Li, Cs, Cd, As, and V were found within the range of 0.01-1.0 (mg/kg) and only Co, Pb, Ni, and Cr were in the range of 1.0 – 10.0 (mg/kg). Se, Sr, Ba, Rb, and Cu were in the range of 10.0 – 100.0 (mg/kg). Metals such as Zn, In, Fe, and Mn were detected in concentrations below 1000.0 mg/kg. And above 1000.0 mg/kg were the elements Al, Mg, Sn, and K. These results revealed that other than Pb, the content of all other metals was below the maximum limits recommended by the Sri Lanka Tea Board. Furthermore, in cluster analysis, Tl, In, Ga, Ag, Cs, and U mainly contributed to the variability across regions. Therefore, based on the limited number of samples analyzed, there is a possibility to use those six elements to identify the region of production. However, this needs further confirmation considering a greater number of samples and the heterogeneity of metal content in the soil in corresponding tea-growing regions to provide a broader understanding of the correlation between levels of the metals in tea leaves and its native soil.
Morpho-molecular genetic diversity and population structure analysis to enrich core collections in tea [Camellia sinensis (L.) O. Kuntze] germplasm of Sri Lanka and India
(Genetic Resources and Crop Evolution, 2023) Kottawa-Arachchi, J. D.; Ranatunga, M. A. B.; Sharma, R. K.; Chaudhary, H. K.; Attanayake, R. N.; Amarakoon, A. M. T.; Gunasekare, M. T. K.; Sharma, B.; Kumar, N.; Sood, V. K.
Despite tea [Camellia sinensis (L.) O. Kuntze] is one of the top non-alcoholic beverages consumed around the world; its genetic and phenotypic diversity is less understood compared to other plantation crops. The study’s aims were to undertake phenotypic and genotypic characterization of Sri Lankan and Indian tea germplasm and to identify diverse accessions to accelerate tea breeding programmes in both countries. A total of 171 tea accessions, comprising 94 Sri Lankan and 77 Indian accessions were used. All the accessions were subjected to phenotyping and genotyping using 28 polymorphic simple sequence repeat (SSR) markers. Based on 16 morphological characters, the first three principal components explained 57.61% and 58.43% of the total variability of Sri Lankan and Indian accessions, respectively. Young shoot pubescence, young shoot pigmentation, serration of leaf margin, and mature leaf colour contributed positively to the grouping of accessions. Based on Neighbor-joining analysis, all Sri Lankan accessions grouped in a single cluster, whereas Indian accessions grouped in two distinct clusters. The Gower’s distance method was the most appropriate than other methods for developing core subsets. Among 21 Sri Lankan core accessions selected, 11 accessions belong to introductions, five TRI-developed cultivars and five estate selections. Among 18 Indian core accessions selected, 11 belong to China types, two Assam types and five Indian recommended cultivars. The current study is the first study to compare tea germplasm of both countries and the results are useful for tea crop improvement programme, conservation and utilization of tea germplasm in India and Sri Lanka in the future.
Selected metal contents of tea produced in different regions of Sri Lanka
(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Harshani, R. K. A. N.; Amarakoon, A. M. T.
‘Ceylon Tea’ is considered as the best in quality among all the teas produced in the world, becoming one of the main income sources of the country. In some instances, changes in the level of metals in tea and other food had been observed due to many reasons. As the accumulation of heavy metals can cause health risks, frequent analysis is strongly advised by regulating authorities. The objective of this study was to determine selected heavy metal levels in Ceylon tea and to assess whether the contents are safe and also to assess whether there are differences between teas produced in different regions of Sri Lanka. In this study, tea samples (0.500g, 6 samples each from a region) from seven tea growing agro-ecological regions of Sri Lanka, known as, Nuwara Eliya, Dimbula, Uva, Uda Pussallawa, Kandy, Ruhuna and Sambaragamuwa were analyzed for selected metal contents using Flame Atomic Absorption Spectrometry. Microwave digestion was used for sample decomposition. The data were statistically analyzed using Minitab 19 software package. The mean concentration (mg kg-1) of metals analyzed in Ceylon tea samples was found to be as follows: Copper (8.93 to 24.85), Iron (120.3 to220.85), Zinc (24.13 to 45.63), Chromium (4.95 to 8.95), Nickel (6.13 to11.33) and lead content was below the limit of detection in FAAS (0.134). According to the results, metal contents follow the order of Fe > Zn > Cu > Ni> Cr > Pb. However, metal levels in tea did not exceed the levels recommended by WHO. Results of one way ANOVA indicated that there were significant differences in the mean levels of metal in tea among different regions of production. Dendrogram constructed based on metal content showed three clusters with Nuwara Eliya tea clustering into one group. In conclusion, Sri Lankan tea is safe for consumption with respect to the metals analyzed and there were significant differences in metal contents in tea grown in different regions of Sri Lanka. A larger number of tea samples along with the soil samples from each region should be analyzed to arrive at better conclusions on identifying the region of production.
Selected metals and polyphenol content in Sri Lankan branded and loose black teas and their compliance with Sri Lankan standards and ISO standards
(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Ranasinghe, N. T.; Amarakoon, A. M. T.
Tea is a widely consumed beverage around the world and recent findings on health benefits have contributed to increased consumption. Due to the long history and reputation for producing high-quality tea, Ceylon tea is well-established in the world tea market. It is also an important part of the Sri Lankan economy. The current study aimed to evaluate some selected metals and total polyphenol levels in black teas available in the local market, to find the adherence to national and international standards. Branded and loose tea samples were randomly selected from the Sri Lankan market. Ten branded samples were used for the analysis of twenty-five metals using microwave digestion and Inductively Coupled Plasma– Mass Spectrometry (ICP-MS) (2 replicates from each brand). For polyphenol content, 15 branded and 15 loose tea samples were evaluated based on ISO 14502-1:2005- Determination of characteristics of green and black tea (2 replicates from each brand). The results of metal analysis were statistically analyzed with basic descriptive analysis. One–way analysis of variance (ANOVA) test at p = 0.05 followed by Tukey’s pairwise comparison was done for total polyphenol analysis. Both were carried out using the Minitab 22 software package. Results revealed that Ag, As, Be, Cd, Cs, Ga, Li, Se, Tl, U, and V were present within 0.01-1.00 mg/kg, while Cr, Co, Ni, Pb, and Sr ranged from 1.00 to 10.00 mg/kg. Cu, Zn, Rb, and Ba were found in the 10.0–100.0 mg/kg range. Mn and Fe were detected below 1000.0 mg/kg, and Mg, K, and Al exceeded 1000.0 mg/kg. Total polyphenol content varied from 14.20% to 27.67%. The findings revealed that the concentration of Cr in all samples was above the maximum limits (1.00 mg/kg) set by the Sri Lanka Tea Board whereas, as (samples 2, 6, and 10 only) and Pb (samples 1 and 4 only) were above the maximum limit in some samples (As max limit - 0.05 mg/kg and Pb max limit - 2 mg/kg). Additionally, all samples exceeded the recommended minimum polyphenol content. These findings emphasize the general compliance with safety standards for metals but highlight the need for stricter monitoring, particularly for Cr levels since it reached 15.02 mg/kg mean value, significantly exceeding the recommended maximum of 1 mg/kg. Further studies with a larger sample size are recommended to validate these results and guarantee continued adherence of Ceylon tea to quality standards.