Browsing by Author "Lochana, E.A.L."
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Item A Comparative Study on Degradability of NBR and NR Latex Gloves(Uva Wellassa University of Sri Lanka, 2021) Manukularathne, W.G.P.D; Sandamali, P.K.N.N; Siriwardena, S.; Lochana, E.A.L.; Senevirathna, A.M.W.K.Natural rubber (NR) and Nitrile rubber (NBR) gloves are two main types of latex gloves used in the personal protective equipment market. In the face of an abrupt increase in the demand and usage of these gloves due to the present Covid-19 pandemic, degradation of these gloves after usage may create an environmental threat. Therefore, a study was conducted to compare the degradable behavior of these products. Both glove types were treated under thermal and hydrothermal, and UV radiation environments. Untreated samples were used as the control. Under thermal, hydrothermal and photo- oxidative treatments, an increase of the swelling index of untreated NR gloves (65.2%) increased by 38.23%, 14.69% and 7.17%, respectively while NBR gloves showed a percentage swelling index increment of 14.52%, 15.56% and 12.12% with compered to the percentage of the swelling index of the untreated sample (28.77%) in the same order of treatments. The average tensile strength of NR was decreased from 16.89 to 15.67, 11.19, and 15.63 MPa while for NBR it decreased from 28.06 to 24.35, 23.93 and 20.56 MPa after the thermal, hydrothermal and UV exposure, respectively. Hydrothermally treated NR gloves showed new peaks suspected as hydroxyl groups and carbon- carbon triple bonds. Spectra of thermally and hydrothermally treated NBR showed identical loss of the peak responsible for the cyanide group. TGA analysis showed that the initial decomposition temperature of NR has reduced from 365.42 ̊C to 364.95 ̊C, 360.63 ̊C and 365.27 ̊C, respectively after the thermal, hydrothermal and UV treatments. NBR gloves also showed the same trend except for hydrothermal treatment where an increase in initial decomposition temperature was recorded. Overall, hydrothermal treatment was the best degradation method for NR gloves among candidates while exposure to UV radiation exhibited the highest degradation potential for NBR gloves. It was also found that removal of cyanide group when NBR gloves were subjected to hydrothermal degradation. Keywords: Fourier transform infrared spectroscopy; Natural rubber; Nitrile Butadiene rubber; Thermo gravimetric analysis; UltravioletItem Comparative Study on Physicochemical Properties of Pot Still and Column Still Palmyrah Arrack(Uva Wellassa University of Sri Lanka, 2020) Prasana, S.; Perera, G.A.A.R.; Lochana, E.A.L.; Anuluxshy, B.Palmyrah arrack is produced either by pot still or column distillation of Palmyrah toddy. This study was conducted to fill the gaps in information on the physicochemical properties of these two types of Palmyrah arrack and to investigate whether they comply with the Sri Lankan Standard (DSLS 919: 2019) requirements. Both arrack samples were collected from two distilleries located in the Jaffna district. Ethanol, total solids, total acids as acetic acid, fixed acids as acetic acid, esters as ethyl acetate, higher alcohol, volatile acidity, reducing sugar, total sugar, total phenols, and vitamin C contents and color and pH of these samples were evaluated. Pot still arrack contained significantly (p<0.05) higher amount of ethanol (29.3 ± 0.6% ), total solids (791.9±17.6 g/100 L), total acids (34.5±3.2 g/100 L), fixed acids (7.7±0.3 g/100 L), volatile acids (26.8±2.9 g/100 L), esters (101.2±1.6 g/100 L), Vitamin C (3.6±0.0 mg/100 g), total phenols (0.63±0.0 g/100 g) and Color (8.1±0.2) than column still arrack (16.0±1.0%,297.6±12.8 g/100 L, 18.4±1.2 g/100 L, 1.8±0.1 g/100 L, 16.6±1.1 g/100 L, 55.3±0.4 g/100 L, 2.9±0.1 mg/100 g, 0.26±0.0 g/100 g & (7.6±0.1) respectively). Meanwhile, total sugar (9.4± 0.14 g/100 g), and reducing sugar (2.73±0.0 g/100 g) contents of pot still arrack were significantly lower than those of column still arrack (15.0±0.7 g/100 g &5.3±0.7 g/100 g respectively). It can be concluded that pot still and column still Palmyrah arracks are significantly different in terms of their physicochemical properties. Both arracks comply with Sri Lankan Standard requirements. Keywords: Palmyrah arrack, Pot still, Column still, Physicochemical properties, Sri Lanka standard requirementItem Comparative Study on the Phytochemical Composition of Medicinally Important Three Ocimum Species Available in Sri Lanka.(Uva Wellassa University of Sri Lanka, 2020) De Silva, S.D.A.I.; Kaliyadasa, P.E.; Lochana, E.A.L.; Marasinghe, P.Ocimum species have been used as an important medicinal herb, since ancient times but no recorded scientific evidence on morphological variations and phytochemical composition in Sri Lanka. Hence this study was conducted to determine the variation of morphological characteristics, total polyphenol content, antioxidant activity, and essential oil composition of three different Ocimum species namely; Ocimum sanctum, Ocimum gratissimum and Ocimum americanum. Healthy and fresh leaves of Ocimum plants were collected from Badulla and Welimada area. Morphological differences in leaves, flowers, roots, stem, and seeds of three Ocimum species were compared visually and recorded. Methanol extraction was performed using dried and powdered leaf samples and analysed total polyphenol content and antioxidant activity for three species using the Folin Ciocalteu reagent method and standard 2,2-diphenyl-1- picrylhydrazyl radical scavenging activity respectively. Hydro distillation was done to extract essential oils from Ocimum sanctum and Ocimum gratissimum and analysed by using Gas Chromatography – Mass Spectrometry method. There were differences and similarities between morphological characteristics among three species. The maximum polyphenol content was recorded in Ocimum americanum and the minimum was recorded in Ocimum sanctum. In determination of antioxidant activity, the highest half maximal inhibitory concentration was recorded in Ocimum americanum and the lowest was recorded in Ocimum gratissimum. There were differences in essential oil composition between Ocimum sanctum and Ocimum gratissimum. It can be concluded that there is a significant variation in morphological characteristics and phytochemical composition of three different Ocimum species available in Sri Lanka. Keywords: Antioxidant, Chromatography, Polyphenol, Scavenging, Spectrometry.Item Comparison of Oil Yields and Chemical Composition of Selections of Cymbopogon Winterianus and Cymbopogon nardus(Uva Wellassa University of Sri Lanka, 2019-02) Mekala, L.K.D.; Ariyasinghe, H.A.E.N.; Lochana, E.A.L.; Alakolanga, A.G.A.W.Citronella (Cymbopogon nardus and Cymbopogon winterianus) is commercially cultivated for oil extraction and Cinnamon Research Station has developed and issued several citronella selections; three superior ‘Heenpengiri’ (HGC 01, EBC 02, and EWC 01) and two superior ‘Mahapengiri’ (KSC 04 and CRC 16) to conserve the wide genetic variability and provide high yielding citronella plant materials. However, a proper scientific analysis on chemical composition and yield of these developed selections has not been carried out. This study was focused on quantitative and qualitative analysis of oil extractions from five selections mentioned above. Steam distillation technique was used to extract the citronella oil; and gas chromatography equipped with Agilent DB WAX UI column was used to analyze the chemical composition of extracted oil. This experiment was carried out using Complete Randomized Design with three replicates. According to the overall analyses, HGC 01 has high quality than other two Heenpengiri selections as it contained Citronellal (3.45%), Citronellol (8.53%) and Geraniol (18.95) values with standard while KSC 04 contained Citronellol (9.12%), Geraniol (34.74%) and Limonene (1.58%) at 95% significant level and it is better than CRC 16. The results showed that there were no significant differences between the oil yield of EBC 02 and HGC 01, HGC 01 and EWC 01 selections. The oil yield of KSC 04 was significantly higher (P=0.045) than that of CRC 16. In conclusion, HGC 01 from Cymbopogon nardus and KSC 04 from Cymbopogon winterianus can be recommended as best selections for commercial extractions.Item Determination of Optimum Antioxidant Ratio for Effective Resistance on Aging of Natural Rubber based Solid Tire Tread Compound(Uva Wellassa University of Sri Lanka, 2019) Perera, C.J.; Alakolanga, A.G.A.W.; Lochana, E.A.L.; Kularatne, S.Antioxidants are highly effective ingredients and have a dramatic impact on the service life of the rubber product although being present at extremely low concentrations. Dosage of these chemicals depends upon the end application. The purpose of this research was to find out the optimum antioxidant ratio for effective resistance on thermo-oxidative aging of natural rubber based solid tire tread compound. Five tread compounds were prepared by varying the n-(1,3-dimethylbutyl)-n’-phenyl-p-phenylenediamine (6ppd) and 2,2,4Trimethyl-1,2-dihydroquinoline (TMQ) antioxidant (AO) ratios (AO1-AO free, AO2 - 2:1, AO3 - 1.5:1.5, AO4-1:2, AO5-2:2). AO5 was designed to test the effect of over dosage of antioxidants. Physio-mechanical properties such as tensile properties, tear strength, hardness, and abrasion resistance of five compounds were investigated before and after thermo-oxidative aging at temperature 70 ℃ for 72 hours according to the ASTM standards. Density and rebound resilience of five compounds were also investigated. According to the results obtained, percentage changing hardness, tensile strength, elongation at break and tear strength of AO1, AO2, AO3, AO4 and AO5 were (1%, 4.34%, 1.73%, 15.70%), (2%, 3.72%, 7.94%, -4.48%), (2%, 5.27%, 11.59%, 21.64%), (1%, 1.40%, 5.52%, 3.57%) and (2%, 3.99%, 1.60%, 14.19%) respectively after aging 72 hours. Hardness, modulus at 300% and abrasion resistance increases as the heat-aging time increases. The rate of decrease of tensile strength, tear strength and elongation at break was higher after aging. Result obtained for rebound was 44%, 46%, 47%, 46% and 48% respectively. Density of all five compounds were same. In conclusion as the percentage changing was minimum in AO4 and it is the best among five ratios under 72 hours aging condition.Item Effect of Fiber Size on Properties of Oil Palm Fiber Waste Filled Natural Rubber Composites(Uva Wellassa University of Sri Lanka, 2021) Madushika, T.G.K.H.; Weerasinghe, U.A.; Edirisinghe, D.G.; Lochana, E.A.L.; Senevirathna, A.M.W.K.The twenty-first century has witnessed remarkable achievements in the rubber industry regarding green technology through the development of natural fiber based rubber composites. A wide variety of natural fibers extracted from coconut, palmyra and banana has been used as fillers in the development of natural rubber (NR) based green composites, most importantly to reduce environmental pollution caused by hazardous powdered fillers and to enhance reinforcement. Oil palm fiber (OPF) is hard, tough and has the potential to reinforce the rubber matrix. Mesocarp part of OPF, which generates as a waste material of palm oil processing mills was used as a filler in this study. The objective was to investigate the effect of size of OPF on cure, physico-mechanical, water absorption and ageing properties of NR composites. A chemical treatment was conducted to reduce fiber size and to improve physico-mechanical properties. Chemical processing with sodium hydroxide, bleaching with sodium chlorate and oxalic acid were conducted to remove residual oil and reduce fiber size. A series of NR composites were prepared with 2 phr OPF by varying its size from 250 μm to below 50 μm. The NR composite prepared without OPF, but with 2 phr of carbon black was considered as the control. Although an increase in properties was expected with the reduction of fiber size, no significant increase was observed. Nevertheless, results showed the highest values for the NR composite prepared with OPF in the size range 125-175 μm in regard to modulus at 300% elongation, tensile strength, hardness, resilience and an average value for water absorption. This revealed even dispersion of OPF in the rubber matrix of the above composite and the results were in agreement with crosslink density indicated by the delta cure value. There was no decrease in tensile modulus and strength after ageing, which indicates high retention of these properties. Overall, results revealed that carbon black in NR composites could be replaced with OPF to manufacture rubber products requiring hardness ranging from 29-36 Shore A. Keywords: Oil palm fiber; Natural fillers; Natural rubber; Cure characteristics; Physico-mechanical propertiesItem Effect of Residual Diammonium Hydrogen Phosphate Content on Properties of Natural Rubber Centrifuged Latex(Uva Wellassa University of Sri Lanka, 2021) Siriwardhana, M.W.H.N.M.; Attanayake, A.; Lochana, E.A.L.; Senevirathna, A.M.W.K.Natural rubber particle, a polyisoprene core is surrounded by a shell of non-rubber components, proteins and phospholipids. Natural PO43- are added to ammonia preserved latex due to the hydrolysis of phospholipid layer around the rubber particle. Although this process contributes to the stability of the latex this could produce a waste sludge; a precipitate of magnesium with phosphate. In centrifuged latex (CL) manufacturing process PO43- are added as diammonium hydrogen phosphate (DAHP) before centrifugation in order to remove residual Mg2+ present in field latex to the level of 80-100 ppm. In most cases, added DAHP will leave excess PO43- in latex as most manufacturers added it without estimating the remaining Mg2+ present in latex. It results in a high amount of PO43- in latex as a considerable amount of PO43- are released from the natural process of hydrolysis with storage time. This study aimed to determine the variation of residual PO43- content of CL with storage time and its ultimate effect on latex property development. A series of centrifuged latex samples were prepared by adding 0 g (control sample), 3 g, 6 g, 9 g, 12 g, and 15 g of 15% DAHP. Changes of the latex characteristics such as mechanical (MST) and chemical stability time (CST), PO43- and Mg2+ concentration, viscosity were determined with time. All the testing were carried out according to ISO procedures. High ammonia preserved CL showed a considerable amount of natural PO43- of about 300-200 ppm with storage time. The PO43- content of latex is not a stable amount and showed several fluctuations with time due to several chemical reactions within the latex sample. The excess amount of PO43- in the latex leads to a decrease in viscosity and stability of latex due to colloidal destabilization. The control sample showed the highest MST (315 seconds) and CST (97 seconds) with storage time than other samples revealing that there is no need for the addition of DAHP if the Mg2+ content of field latex is below 100 ppm in manufacturing CL. Keywords: Latex; Diammonium; Phosphate; Magnesium; Destabilization; ColloidalItem Extraction of Natural Food Colorant by using Bovitiya (Osbeckia stellata) and Evaluation of its Stability under Different Processing Conditions(Uva Wellassa University of Sri Lanka, 2020) Kularathne, M.D.H.; Ranpatabandi, T.; Alakoklangala, A.G.A.W.; Lochana, E.A.L.Numbers of phytochemicals have been derived directly or indirectly from natural sources in the form of food supplements, oil, nutraceuticals, and color pigments. Herbal medicines have been used for the treatment of various disorders in Ayurveda medicine and all over the world due to their numerous health benefits. Bovitiya (Osbeckia stellate) is a medicinal plant which contains Anthocyanins that is responsible for the various colors of the plant. Anthocyanins have a wide range of pharmacological properties and play a major role in the food industry as natural colorants due to its possible health benefits and safety issues compared to the synthetic dye. In this study, Bovitiya fruits were used to extract anthocyanin pigment. Weighted fruits were blanched to degrade the enzymes responsible for browning, before the extraction procedure. The experiment was carried out using only 50% ethanol solution, according to 1:5 (w/v) ratios. The total monomeric anthocyanin content was measured using a pH differential method. Physiochemical properties and stability under different processing conditions (temperature, pH) were estimated. The stability of color extract was evaluated for one week using standard color codes. The total anthocyanin contents were 62.20 mg kg-1 under the optimum condition set at temperature 60⁰C, 300 rpm for 3 hours. The study demonstrated that the very dark purple extract of the fruits is stable under low pH values (≤4.7) and unstable under alkaline (≥7) conditions. Also found to be sensitive to high temperature were the conditions like 121⁰C for 10 sec. Microbiological stability was tested using the standard method. Total plate count was (3.23±0.2 CFU mL-1 ) and yeast and mold count was (2.33±0.2 CFU mL-1 ) and Coliform, E. coli was not detected. The study carried out on Bovitiya provides information to tap its potential as a colorant in acidic and neutral food. Keywords: Food color, Bovitiya, Anthocyanin, pH differential method, PhysiochemicalItem Formulation and Standardization of Face Wash using Palmyrah Pulp and Aloe Vera Gel(Uva Wellassa University of Sri Lanka, 2020) Vinoja, G.; Alakolanga, A.G.A.W.; Lochana, E.A.L.; Anuluxshy, B.; Kirushanthi, A.The facial skin is exposed to pollutants, microbes and old skin, necessitating the use of a face wash. Many, different face washes are available in the market, but most of them contain harmful synthetic chemicals which induce skin allergies as well as premature ageing of the skin. On the other hand, the Palmyrah fruit pulp has been reported to possess antioxidant properties and aloe vera gel has been being used for its moisturizing and soothing properties and both these plants are locally available. Hence this study was aimed at formulating a face wash containing Palmyrah pulp and Aloe vera gel. Six different types of face washes (F1, F2, F3, F4, F5, F6) were formulated by changing the ratio of Palmyrah pulp to Aloe vera while keeping the amount of the other ingredients constant. Here methylparaben and propylparaben were used as preservatives, sodium lauryl sulfate as a forming agent, propylene glycol as a humectant, and triethanolamine as a neutralizer, carbopol 940 as a gelling agent and water as a solvent. The total phenolic content of the different face washes was determined using UV spectroscopy and Gallic acid as the standard. The results showed the face washes containing pulp to aloe vera in 5:0 (F1) and 2:3 (F4) ratios contained the highest amount of total phenols. These two formulations were subjected to the physiochemical analysis. pH, viscosity, foamability, spreadability, thermal stability, washability, non-volatile matter, total surfactant, and density of the face washes were found to be within the limits expected for a facial cleanser. The anti-microbial activity of these two face washes was determined using Turbidometric method and the results demonstrate that these face washes possess the substantial anti-microbial activity and that F4 is more efficient than F1. Sensory evaluation to evaluate the appearance, colour, fragrance, texture, foamability, and washability of the face washes was conducted using thirty untrained panellists and 5-point Hedonic scale, and F4 was chosen as the best formulation based on the results. This study concludes that the formulated face wash (F4) has antioxidant and antimicrobial properties and is preferred in terms of texture, spreadability, foamability, washability, texture, colour and appearance. Keywords: Aloe vera gel, Antioxidant, Anti-microbial activity, Palmyrah fruit pulp, Total phenolic contentItem Green Synthesis of Zn Nanoparticle (ZnO NPs) Using Palmyrah Resource and Evaluation of Its Antimicrobial Property(Uva Wellassa University of Sri Lanka, 2021) Nirosha, A.U.; Vinujan, S.; Lochana, E.A.L.; Arachchige, M.P.M.; Srivijeindran, S.Borassus flabellifer is a tree found in the tropical belt of Sri Lanka and almost all parts of the tree can be used for various purposes like food, medicine, and others. Mostly, the leaf has been used to make handicraft items and is popularly known for this only but other than this, there is a potential for the leaf being used for various purposes. Only very few studies were conducted to evidence the medicinal importance of palmyrah leaf. The aim of this work is associated with plant-mediated nano- particle synthesis through developing low-cost, eco-friendly processing using palmyrah leaf extract and zinc sulphate and sodium hydroxide as precursor solution. The artificial synthesis of ZnO is assisted by chemical processing and leaving several hazardous effects on the world. The nanoparticles synthesized were characterized using X-ray diffraction analysis and the antibacterial activity was evaluated by the agar well diffusion method. The X-ray diffraction (XRD) spectrometer was used to determine the crystalline size of nanoparticles synthesized as 20 ± 6 nm at the wavelength of 517 nm. Antimicrobial activity for two different concentrations of ZnO nanoparticles (50 and 100 mg/ml) was studied for Escherichia coli. A significant inhibition activity was observed for the tested two concentrations and the maximum activity (18 mm) was observed from the highest concentration. An attempt is employed for the synthesis of ZnO nanoparticles using leaf extract of Borassus flabellifer in an environmentally friendly manner. In this green nano-particle synthesis process, palmyrah leaf extract has functioned as a reducing and capping agent. Green aspects of ZnO nanoparticle synthesis could be recommended as an alternative to high thermal chemical processing. Further characterization for associated phytochemical compounds and any toxic factor will assist to incorporate this nanoparticle for developing any value-added product from palmyrah in the future. Keywords: Borassus flabellifer; ZnO nanoparticle; XRD analysis; Antibacterial activityItem Intercalation of Acarbose into Sodium Montmorillonite for Sustained Release Formulation(Uva Wellassa University of Sri Lanka, 2020) Mihiravi, H.K.S.P.; Lochana, E.A.L.; Rathnayake, S.I.; Alakolanga, A.G.A.W.; Senarathna, K.G.C.; Premarathne, E.P.N.; Wijesekara, K.B.Among the numerous antidiabetic drugs, acarbose is the most extensively used digestive enzyme inhibitor for the treatment of Type-II diabetes. A simple and rapid UV-Vis spectroscopy method reported in the literature was modified and successfully implemented for the determination of acarbose in aqueous media. The method is based on the formation of a green-colored complex of acarbose with alkaline potassium permanganate. Concentration (in the range of 10-50 ppm) is proportional to the visible light absorbance at 426 nm wavelength, therefore, the above parameters were selected for the quantitative determination of acarbose in aqueous solution. The Beer–Lambert law is obeyed in the above-mentioned range with a coefficient of determination (r2 ) value of 0.9826. The acarbose concentration in commercial tablets was determined using this method and the recovery was 99.65 % for 40 ppm solution. Short biological half-life and more side effects of acarbose have been recurring problems, owing to its low bioavailability and low patient tolerance, respectively. The controlled release of a therapeutic agent to patients is gaining prodigious importance during the recent time and clay minerals play a major role in modulating drug delivery. The present work is focused on the intercalation of acarbose into montmorillonite (MMT) as a controlled release drug carrier. MMT is an aluminosilicate clay composed of tetrahedral layers of silica stacked between octahedral layers of alumina with negatively charged surfaces. Due to its high cation exchange capacity and large specific surface area, MMT is extensively used in the formulation of various pharmaceutical products. In this study, acarbose was successfully incorporated into MMT by stirring MMT in a 100 ppm acarbose solution and showed 22.4% intercalation at pH 6. Acarbose intercalated MMT was characterized by X-ray diffraction and Fourier transformed infrared and the presence of N-H stretching peak at 1632 cm-1 and increase of d-spacing confirmed the successful intercalation of acarbose into the interlayers of MMT. The releasing properties of the synthesized acarbose-MMT composite would be investigated in the future. .Keywords: Acarbose, Montmorillonite, Intercalation, Drug delivery, CharacterizationItem Isolation of Colourants from Crude Green Tea Extracts as a Substitute for Commercially Available Synthetic Food Colourants(Uva Wellassa University of Sri Lanka, 2021) Liyanage, S.P.; Lochana, E.A.L.; Ellepola, V.P.; Wijesinghe, W.A.J.P.A natural food colour is any dye, pigment or any other substance obtained from a natural source. The demand for natural food colours in the international market is increasing rapidly due to the increasing public awareness on the harmful effects of synthetic food colourants. Hence this study was aimed at isolating food colourants using green tea based refuse tea and dust grade as a value added product. Accordingly, colour extraction of refuse tea (8 % moisture, 5.58 % ash, 15.51 % crude fiber, 2.06 % fat and 19.68 % protein) and green tea dust (6.06 % moisture, 5.63 % ash, 14.55 % crude fiber, 2.07 % fat and 15.57 % protein) was initially done by sonication and simple water bath techniques. The most desirable samples were then selected based on the colour intensity values (b*) and absorbance values. The selected samples were stabilized with 3 % carrageenan which converted the filtrate into a gel. The stability of the colourants was studied against pH, concentration and time-temperature combinations. The consumer preference for the products were studied using a structured sensory evaluation. According to the results yellowness (5 Y8/10 to 5 Y8/12) could be expected in 3 to 4 pH range in refuse tea based colourant and yellowness (5 Y8/6 to 5 Y8/10) could be expected in 3 to 6 pH range in the green tea dust based colourant. It was observed that with the increase of the temperature darkness of the colourant significantly rises, especially from 60 ºC and above, which resulted in a hue approximated to caramel black. Both colourants showed yellow hues from 0.3 to 2 % v/v concentration level. Moreover both colourants are having considerable levels of polyphenol content ,antioxidant activity and caffeine content, which contribute to human health promotion. Therefore, it can be inferred that developing colourants using crude green tea extract to be sustainable and safe alternative for synthetic colourants used in the food industry. Keywords: Dust; Extraction ; Green tea; Natural food colour; Refuse teaItem A Novel Process to Manufacture Low Protein Contained Centrifuged Latex(Uva Wellassa University of Sri Lanka, 2020) Hansani, P.M.G.S.; Sudusinghe, Y.C.Y.; Senevirathna, A.M.W.K.; Lochana, E.A.L.; Sandamali, P.K.N.N.Removal of protein in Natural Rubber (NR) latex has been a focus of great importance as some users face serious allergy issues when they exposure to NR latex-based products. Therefore, in this study, an attempt was taken to develop a commercially viable and environmentally friendly hybrid route by combining fractionation and creaming processes, to manufacture quality centrifuged latex with reduced protein level. Firstly, preserved NR field latex was fractionated at four different Dry Rubber Content (DRC) levels: 15%, 18%, 21%, and 24%. Subsequently, all fractionated and diluted field latex samples at 10% DRC were creamed up to 30% DRC using sodium alginate at 20 phr concentration. Creamed latex obtained were then subjected to the centrifugation process. Fractionated Creamed Centrifuged Latex (FCCL) samples were compounded according to the basic formula and cured in a drying oven at 120 ℃ for 20 minutes. Latex properties and their film properties were studied according to the standard test procedures and compared with Single Centrifuged Latex (SCL) and Double Centrifuged Latex (DCL). The FCCL sample fractionated at 15% DRC (15% FCCL) showed the lowest nitrogen content than other centrifuged samples while other samples follow the order of 18% FCCL< 21% FCCL < 24% FCCLItem Optimization of Glove Mixing Process of Gammex Powder Free (GPF) Product to Overcome Scum Formation(Uva Wellassa University of Sri Lanka, 2019) Dissanayake, R.M.T.; Samaraweera, T.M.; Lochana, E.A.L.; Alakolanga, A.G.A.W.Hevea brasiliensis latex is used to manufacture surgical gloves. GPF gloves are low in residual proteins and powder. Hence they are less susceptible to allergies. Scum formation is a major drawback in compounding process which contains of two major phases, phase 1 (heat prevulcanization) and phase 2 (ambient prevulcanization). The major issue of the current process is scum formation during prevulcanization stage. The main reason for scum formation is the lack of stability at elevated temperature, high dosage of ZnO which forms excessive zinc amine complexes and due to less Brownian motion of curing agents. The trials were done by changing 3 main factors such as Potassium laurate (PL) level, ZnO% and mode of cure pack. As per the trials, changed PL dosage as 50% in each phases, interchanged ZnO dosage in phase 1 (lower dosage) & phase 2 (higher dosage), individual dispersions of curing agents were introduced. Anyhow, ZnO trial was failed due to lack of ZnO for the activation of prevulcanization process. According to the statistical analysis using Minitab 16 software, the P value (<0.05) at 0.05 level of significance proved that there was an interaction between PL level and curing method. With the PL 50% in both phases and adding individual dispersions, the scum level was reduced from 8% to 0.5%. Gloves were prepared to test whether the chemical adjustment was affected for final glove quality. The P value (>0.05) at 0.05 level of significance proved that there was no significance difference in tensile strength. The modulus was more than required and it is cost effective. In conclusion, the scum formation can overcome by changing PL level and by adding individual dispersions. Furthermore, it is beneficial to overcome glove defects like scum, dirt hole and it allows opportunity for the process optimization of GPF product.Item Preparation and Characterization of Deproteinized Crepe Rubber using a Serin Type Proteolytic Enzyme(Uva Wellassa University of Sri Lanka, 2020) Chandramali, T.H.D.S.; Sudusingha, Y.C.Y.; Siriwardena, S.; Lochana, E.A.L.; Senevirathna, A.M.W.K.A serin type Proteolytic Enzyme (PE) was used as a substitute for traditionally used papain which has no reliable supply at present in the local market, for the manufacture of Deproteinized Crepe Rubber (DPCR). Field latex was coagulated by different PE dosages varying from 1 to 4 ml with 1 ml intervals per litre of the diluted field latex at 10% DRC and matured for 72 hours. The control sample was coagulated within 24 hours using 1% formic acid and all coagula were converted into pale crepe form. The impact of the maturation period (24-72 hours) on raw rubber properties was also studied using the selected sample which meets the lowest Nitrogen Content (NC) among all the candidate samples. Raw rubber properties, curing characteristics, and physicomechanical properties of all the vulcanizates were studied. All enzyme-treated samples showed lower NC (0.10- 0.14%w/w) than the control (0.31%w/w). It was noticed that the increase of PE volume and maturation period reduced the NC in the samples. Raw rubber properties of the enzyme-treated samples with a 72-hour maturation period have complied with the required specifications of DPCR except for the Plastic Retention Index (PRI). It was found a reduction of PRI and ash content while increasing in Po values with the increment of PE dosage and maturation period. However, the enzyme treatment (4ml/liter) with a 24-hour maturation period was able to achieve the slightly higher PRI value (63.3%) than the recommended value (60%) for both control and DPNR. It was found that curing time (T90) of the control sample was higher than the enzyme-treated samples and the control sample showed better tensile strength than the enzyme-treated samples due to the protein reinforcement effect and higher crosslink density. Overall, it could be concluded that the selected enzyme has the potential to use it for manufacturing DPCR. Keywords: Deproteinized crepe rubber, Nitrogen Content, Maturation period, Raw rubber propertiesItem Shelf Life Extension of Minimally Processed Lettuce Leaves (Lectuca sativa)(Uva Wellassa University of Sri Lanka, 2020) Thilakarathna, K.G.C.R.; Wijewardana, R.M.N.A.; Lochana, E.A.L.; Wijesinghe, W.A.J.P.Cold storage is one of the best methods to maintain the qualitative and quantitative properties of Minimally Processed lettuce (Lectuca sativa). The study was conducted to optimize the shelf life of minimally processed lettuce which were stored in three different packing materials. Lettuce which was obtained from same cultivation with similar maturity level was stored in Biaxially-oriented polypropylene (BOPP) Antifog 35 micron, Polypropylene (PP) Micro Perforated and Biaxially-oriented polypropylene (BOPP) Antifog Breathable 40 micron at 12ᵒC were evaluated separately for Physiological Loss in Weight, pH, Total Soluble Solids, Total Chlorophyll Content, Ascorbic Acid Content, Total Phenolic Content, Total Anthocyanin Content, Visual Quality Assessment, Total Plate Count and sensory evaluation at the one-day interval. The minimally processed lettuce stored in BOPP Antifog Breathable 40 micron, BOPP Antifog 35 micron, and PP Micro Perforated had shelflife of ten days, eight days, and three days respectively. Lettuce from both BOPP Antifog Breathable 40 micron, and BOPP Antifog 35 micron packs reported a significantly lower physiological loss in weight throughout the storage period. In the tenth day of storage, the lowest total soluble solid (3.7±0.09) was with the BOPP Antifog Breathable 40 micron pack. The highest pH value (6.61±0.03) and total chlorophyll content (2.22±0.04) were recorded in the BOPP Antifog Breathable 40 micron pack on the last day of storage. PP Micro Perforated pack, BOPP Antifog 35- micron pack, and BOPP Antifog Breathable 40-micron pack failed the visual quality assessment on the third day, the seventh day, and the tenth day of storage respectively. The results indicate that BOPP Antifog Breathable 40 micron film is the most suitable packaging material for minimally processed lettuce. Keywords: Lettuce, Minimally processing, Cold storage, Packaging materialsItem A Study on Sustained Drug Releasing Properties of Acarbose Intercalated Na- montmorillonite for Potential Pharmaceutical Applications(Uva Wellassa University of Sri Lanka, 2021) Kawmudhi, P.A.S.; Lochana, E.A.L.; Premarathne, E.P.N.; Alakolanga, A.G.A.W.; Rathnayake, S.I.Acarbose is a well-known synthetic drug, which commonly treats type II diabetes. For diabetic patients, acarbose must be administered multiple doses a day to keep a stable glucose level in the body due to short biological half-life. Therefore, drug formulations with sustained releasing properties are developed using stable carriers like, Montmorillonite (MMT) due to its unique structure and properties. In this study, acarbose intercalated clay formulations were synthesized and their sustained releasing properties tested. Acarbose solution (100 ppm) was stirred with MMT (1 g) for 24 h at 4–8 pH. The highest intercalation of acarbose was observed at acidic pH due to electrostatic interactions between negatively charges clay layers and protonated acarbose molecules. The concentration of acarbose in aqueous solution was determined using the UV-Vis spectroscopy method. The calibration curve (2–40 ppm) of standard acarbose (r2 =0.9826) at 426 nm, was used for calculating the acarbose intercalation percentages. 2.18 mg g-1 (43.77%) and 5.1 mg g-1 (52.27%) of acarbose intercalated into MMT at pH 6 and the interlayer space of unmodified montmorillonite has been increased from 1.185 to 1.310 nm and 1.403 nm upon acarbose intercalation at 50 ppm and 100 ppm initial acarbose concentrations, respectively. This concludes that acarbose has been successfully intercalated into the interlayers of montmorillonite and the intercalated amount increased with increasing the initial acarbose concentration. Increased intensity and broadening of the peak corresponding to vibrations of OH groups (3687–3125 cm-1) was observed in FTIR spectra of acarbose intercalated montmorillonite, which may due to the presence of acarbose on or between the layers of montmorillonite. The in-vitro drug releasing properties of acarbose from acarbose intercalated montmorillonite was tested in artificial intestinal condition (pH 7.4 PBS solution) using dialysis tube method. Acarbose releasing from the montmorillonite matrix was gradually increased in the first 8 h and slow release was observed after that. Pseudo-second order kinetics model showed a good fit (r2= 0.9767) for the acarbose releasing data suggesting the release of acarbose from MMT matrix involves chemical desorption. Overall, this study demonstrates the potential applications of montmorillonite as matrix material for sustained release drug formulations for future pharmaceutical studies. Keywords: Acarbose; Montmorillonite; Sustained drug releasing; XRD; FTIR