Chemistry
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Item Influence of pumpkin seed powder on the characteristic properties of whole wheat cake(Elsevier eBooks, 2024) De, Suprakash; Bharti, D.; Pradhan, B. K.; Behera, H.; Kim, N. M.; Wickramarachchi, S.; Sarkar, P.; Pal, K.Pumpkin seeds are a good source of unsaturated fatty acids, dietary fibers, and minerals. It can be used as a food supplement as the nutritional value of the seeds is relatively high. This study incorporates PSP (pumpkin seed powder) in varying amounts (0%, 5%, 10%, 15%, and 20%) in cake samples. Afterward, their effects on physicochemical, thermal, mechanical, and electrical characteristics were observed. Adding PSP to the cake recipe significantly increased the porosity of the cake by only up to 10% PSP incorporation. The PSP improved the hardness and other textural properties of the cake samples. Also, we can deduce that the water retention capacity of the cake samples increased with the addition of PSP, which increased the moisture content of the cake samples. From the results, we can observe that the browning of the cake increased with the incorporation of PSP in the cake samples. From all the characteristics, we can conclude that the cake sample with 10% PSP had the best texture. This means that PSP can be incorporated into cake samples only up to 10% without compromising the texture and taste.Item Effect of pumpkin seed powder on the properties of cake batter prepared with whole wheat flour(Elsevier eBooks, 2024) De, Suprakash; Bharti, D.; Pradhan, B. K.; Behera, H.; Kim, N. M.; Wickramarachchi, S.; Pal, K.; Sarkar, P.Nutrition plays a crucial role in overall health. Recently, different fruit and vegetable seeds have been incorporated into various food products to increase their nutritional values. Due to its higher nutritional content, the research community has recently explored pumpkin seed powder (PSP) as an ingredient in different bakery products. In the current study the batter composition prepared by whole wheat flour at varying PSP concentrations (5%, 10%, 15%, and 20% w/w) has been studied. The obtained results from the current study suggested that incorporating PSP significantly alters the color, texture, and microstructure of the prepared batter samples. Also, the water retention and air incorporation capacity of the batter samples showed a significant increase after the PSP incorporation. From the 2,2-diphenyl-1-picryl-hydrazyl-hydrate scavenging assay, the antioxidant properties of the prepared batter samples were analyzed. The results suggested an increased antioxidant activity after PSP addition. Though PSP adds to the nutritional value, adding PSP greater than 10% adversely affects the texture of the batters. With 10% of PSP replacement the prepared batter showed a balanced textural property in our study.Item Potential of bio fabricated Annona glabra - silver nanoparticles to control Aedes aegypti and Aedes albopictus(, Proceedings of the 1st International Conference on Frontiers in Chemical Technology, Institute of Chemistry Ceylon, 2020) Aberathna, A.A.A.U.; Amarasinghe, L.D.; Sithara, W.S.; Wickramarachchi, S.; De Silva, C.R.Bio synthesized silver nanoparticles using Annona glabra leaf extract (An-AgNPs) as the reducing and stabrlizing agent were assessed as a novel larvicide against dengue vector mosquito larvae. The fresh leaves of A. glabra were crushed well and heated with distilled water under 70 0C for I hour. The supernatant was mixed (10% and 20% v/v of total volume) with 5 mM AgNO, to synthesize AnAgNPs. Formation ofAn-AgNPs were confirmed bythe color change and by appearance ofSPR peak in the Uv-vis spectrum and characterized by Dynamic Light Scattering (DLS), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared spectroscopy (FTIR). lhe larvicidal activity of An-AgNPs was assessed against the third instar larvae of Ae. aegypti ^nd, Ae. albopictus, under the laboratory conditions (2 -10 mg/L). The change ofsolution color from yellow to dark brown/black and the SPR band at 435 nm confirmed the formation of An-AgNPs. According to SEM; An-AgNPs were spherical in morphology. FTIR analysis detected that An-AgNPs are capped and stabilized with biomolecules of A. glabraleaf ltZl9 (C=O stretching), 1366 (CH2 bending) and 3500-3200 (N-H and O-H stretching) and l2l7 cm-' (C-O stretching)i. The LCro of An-AgNPs (10%) and An-AgNPs (20%)againstthethirdinstarslarvaeofAe.aeglptiafter24hourswere5.2gand2.43mglland of Ae. albopictus were 3.02 and 2.51 mg/L respectively. The LC* of An-AgNPs (I0%) and An-AgNPs (20%)againstthethirdinstarslarvaeof Ae.aegyptiafter48hourswerel.5l andl.lT mg/Landof Ae. albopictus were 1.14 and 2.i0 mg/L respectively. The LC,n ofleafcrude plant extract against the third instars larvae of Ae. aegTpti after 24 and 48 hours were 5.9455 and 3.5485 mg/L and for the third instars iaruae of Ae. albopictus were 5.0040 arrd2.7346 mg/L respectivdy. This study shows that AnAgNPs is efficient in controlling mosquito larvae.Item Potential Antibacterial Secondary Metabolites froe an Enadolichenic Fungus Inhabiting a Lichen Collected from Negombo Lagoon, Sri Lanka(International Postgraduate Research Conference 2019, 2019) Weerasinghe, W.R.H.; Gunawardhana, M.H.A.Y.; Wickramarachchi, S.; Attanayake, R.N.; Weerakoon, G.; Paranagama, P.A.With the revelation of intriguing bioactive properties from natural sources, the thirst to investigate more into the mysteries of nature has immensely expanded. Endolichenic fungi (ELF) became an interesting source during the recent past in this search for novel bioactive compounds and literature sources provide evidence of many such bioactive compounds isolated from these interesting organisms. These ELF asymptomatically live inside the lichen thallus which is formed by the symbiotic relationship of fungi with an algae or a cyanobacteria. A total of 31 lichens were collected from mangrove plants in Negombo lagoon and their molecular identification revealed that they belonged 10 different species. Healthy lichen thalli were surface sterilized and were cut into small segments and plated on 2% Malt Extract Agar (MEA) medium supplemented with 0.01% streptomycin in order to obtain ELF. The obtained pure cultures of ELF were identified using molecular techniques. DNA was extracted using CTAB method and its quality and quantity were determined by agarose gel electrophoresis. DNA was diluted accordingly and was subjected to Polymerase Chain Reaction (PCR) to amplify fungal ITS rDNA region using universal primers. PCR amplification was tested using agarose gel electrophoresis and the full sequences were obtained. Ethyl acetate crude extracts of 18 such identified ELF strains were subjected to anti-bacterial assay against Escherichia coli and Staphylococcus aureus using agar well diffusion method. The species Xylariafeejeensis isolated from the lichal Graphis librata showed remarkable activity against the two bacterial strains on par with the positive control Azithromycin. The assay was carried out using 100 gl of the extract and the positive control (5 mg/ml). The inhibition zone diameters (in cm) against E coli and S. aureus for the ftmgal crude were 1.9 and 2.2 respectively and for Azithromycin was 2.2 against both. In order to isolate the active compounds, a larger crude of the same was obtained and partitioned into Hexane, Chloroform and tvlethanol fractions based on polarity. The assay results for the three fractions revealed that only Hexane and Chloroform fractions possessed anti-bacterial potentiality. Subsequently, silica gel normal phase column chromatography was performed for fur-tha- fractionation. Collected 6 fractions from the column for Chloroform fraction showed inhibition diameters of 1.9, 1.9, 1.5, 1.2, 1.3, 1.1 against E. coli comparable with 2.2 of Azithromycin and 2.4, 2.2, I .4, 0.0, 03,0.0 against S. aureus comparable with 2.5 of Azithromycin. The fraction 1 and 2 showed highest activity against both bacterial strains and fraction 4 and 6 showed lowest activity against E. coli and none against S. aureus. Further isolation is being carried out for active fractions and the structures of obtaining active compounds will be elucidated using spectroscopic methods.Item Two new bioactive poliketides from Culvularia trifolii, an endolichenic fungus isolated from Usnea sp., in Sri Lanka(2015) Samanthi, K.A.U.; Wickramarachchi, S.; Wijeratne, E.M.K.; Paranagama, P.A.Item Root growth promotion of Ficus species during air-layering(2010) Gamlath, M.; Abeywickrama, K.P.; Wickramarachchi, S.Three chitosan concentrations (1%, 3%, 5% w/v) were tested for their root growth promotion properties in air-layering of three popular ornamental Ficus species namely Ficus triangularis, Ficus microcarpa and Ficus benjamina. Subsequently, these treatment responses were compared with a rooting hormone (naphthalic acetic acid) and an organic root promoting extract (Root Most) available in the local market. Tap water was used as the control. Air-layered plants were further subjected to export simulation for 14 days at 12-14 0C and 90% relative humidity (RH) with the aim of lengthening the storage period. 3% (w/v) chitosan treatment concentration was shown to promote the root growth significantly. 3% (w/v) chitosan treatment resulted in the highest mean root length of (15.3 cm) in F. triangularis compared to the 10.3 cm of tap water control. Similarly, highest mean root length of 38.8 cm was recorded for F. microcarpa for 3% (w/v) chitosan treated layers compared to 14.8 cm of tap water treated layers. Further, the highest mean root density of 3.17 was recorded for 3% (w/v) chitosan treated layers of F. triangularis. A cost effective packaging system was developed during this research which could be utilized in cold storage of air-layers during air or sea freight.Item Isolation of the bioactive metabolites in the endolichenic fungus, Daldinia eschscholzii, occurring in the lichen, Parmotrema sp. in Sri Lanka(Sri Lanka Association for the Advancement of Science, 2013) Samanthi, U.; Wickramarachchi, S.; Paranagama, P.A.Item Isolation and molecular identification of endolichenic fungi inhabiting in the lichen Pseudocypherllaria sp. available in Sri Lanka(Sri Lanka Association for the Advancement of Science, 2013) Pary, F.; Kulasekera, C.; Wickramarachchi, S.; Paranagama, P.A.Item A new curvularin macrolide from an endolichenic fungus, Curvularia trifolii, isolated from Usnea sp., in Sri Lanka(University of Kelaniya, 2014) Samanthi, U.; Wickramarachchi, S.; Paranagama, P.A.Item Antioxidant and antifungal activities of secondary metabolites of the endolichenic fungus, Penicillium pinophilum isolated from the lichen Pseudocypherllaria sp. available in Sri Lanka(Institute of Chemistry Ceylon, Adamantane House, Rajagiriya, Sri Lanka, 2013) Kulasekara, C.N.; Wickramarachchi, S.; Paranagama, P.A.