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U n i v e r s i t y of P e r a d e n i y a

The Institutional Repository of the University of Peradeniya is the University's digital gateway to scholarly knowledge and research excellence. Established as the next phase of the Digital Library initiative launched by the University Library in 2011, it preserves, showcases, and provides open access to the intellectual output of the University community.

Through a rich collection of research articles, conference proceedings, theses, dissertations, and other scholarly works, the repository enhances the visibility, accessibility, and long-term preservation of knowledge, extending the global reach and impact of the University of Peradeniya’s academic and research contributions.

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Demand estimation of household food waste: A case from Kurunegala district
(University of Peradeniya, Sri Lanka, 2023-09-20) Thilakarathna, G.D.S.; Weerasooriya, S.A.
Household food waste is driven by consumer habits and behavior. It differs with demographic, social, and economic factors. This study aims to determine whether household food waste is a luxury good and identify how demographic and socioeconomic factors affect household food waste. For this, a Quadratic Almost Ideal Demand System (QUAIDS) model was used, which is augmented with demographic, socioeconomic, and expenditure controls. Data were obtained in October 2022 through an online survey from 195 respondents living in the Kurunegala District of Sri Lanka. Data on food habits and quantity of food waste in food categories based on the consumption of most households in Sri Lanka, namely, rice, other cereals, pulses, fruits, vegetables, meat, fish, dairy products, eggs, and miscellaneous foods. Values (expenditure) on the waste of each food category were calculated by multiplying expenditure on each food category with the percentage of waste, and then expenditure share on each category of household food waste was obtained. The demand system estimation showed that all expenditure elasticities for all food waste categories as positive, indicating that they are normal goods. Food waste categories were identified as luxury goods or necessary goods. Waste of rice, other cereals, pulses, fruits, vegetables, and miscellaneous food in the household were necessary goods, while the waste of meat products, fish, dairy products, and eggs food categories were luxury goods. Expenditure share on household food waste differs with residence area. High- income group of households shows higher expenditure shares on food waste, lowest in the low-income group, and in between among middle-income households. Expenditure shares and expenditure elasticities vary with demographic, social, and economic factors. According to the study, most households practiced different management practices and they had positive attitudes toward minimizing household food waste.
Estimating the technical efficiency of small-scale inland fisheries: A case from Vavunikulam Tank
(University of Peradeniya, Sri Lanka, 2023-09-20) Nilusha, S.; Weerasooriya, S.A
The fisheries sector comprises coastal, offshore, and inland fisheries. Inland fisheries specifically involve the exploitation of fishery resources from inland water environments. Vavunikulam is one of the largest tanks in the Mullaitivu District, Northern Province, Sri Lanka, and holds immense potential for inland fishing. This study aims to determine the level of technical efficiency and identify factors affecting the technical efficiency of small-scale fishing households. This study also focuses on the role of the National Aquaculture Development Authority of Sri Lanka (NAQDA) and the fishing society in this context. Out of the 60 fishing households using the Vavunikulam tank, 50 fishermen were selected using a convenient sampling method. Data were collected with thoughtfully designed questionnaires. A Cobb-Douglas stochastic frontier approach with an inefficiency model was used to estimate the technical efficiency and identify the determinants of the efficiency of fishermen. The maximum likelihood parameter estimates showed that fishing output was significantly and positively correlated with the number of fishing gear used and the duration of fishing. This indicates that optimizing input usage can lead to increased fish output levels. The study found that 69.80% of the deviation of observed fishing output from frontier output was due to technical inefficiency. The estimated mean of technical efficiency of the sample fishermen was about 86%, suggesting that by efficiently utilizing existing resources, the technical efficiency could be enhanced by 14%. Further results showed that education level, experience, and income from other sources were found to have a negative and significant effect on technical inefficiency, and age was found to have a positive and significant effect on technical inefficiency of fishing output. Therefore, government and policymakers should take necessary actions and foster policies to improve the technical efficiency of fishermen through providing formal as well as informal education, training programs, and credit facilities.
Nutrient analysis of cultivars of cucurbita spp. (pumpkin) grown in the dry zone of Sri Lanka
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2022-10-28) Ruwanthika, K.O.G.H.; Munasinghe, M.L.A.M.S.; Marapana, R.A.U.J.
Different Cucurbita spp. generally recognized as pumpkin, is a commonly grown vegetable in dry and intermediate zones of Sri Lanka. C. maxima and C. moschata are popular cucurbits that include different types of open-pollinated, hybrid and imported varieties. This study aimed to conduct a nutrient analysis of seven pumpkin cultivars collected from Kudaoya in the Monaragala District to identify the differences in the nutrient composition among the selected cultivars. The study area comes under the dry zone low country 1b (DL1b) agro-ecological region. Rajah, Leela, Malbaro, Batana, Bingha, Katana and Meemini were the selected pumpkin cultivars, and out of these, Rajah, Leela and Katana were recognized as C. maxima varieties. In contrast, Bingha, Meemini, Batana and Malbaro were recognized as C. moschata varieties. All the selected cultivars were collected within a range of 5 km from the Kudaoya town and at their fullest harvestable maturity in the Maha season. The collected samples were stored under ambient temperature, and the flesh part of each cultivar was powdered before the nutrient analysis. In the nutrient analysis, the proximate composition, Fe, Mg and K compositions and the anti-oxidant (AO) activity in different pumpkin cultivars were evaluated using standard analytical methods (Protein-Bradford assay, Carbohydrate-Phenol sulphuric method, Lipid content-Bligh and Dyer method, Crude fibre-Weende method, Moisture level- Rapid moisture analyser, Minerals-Atomic absorption spectroscopy method, AO activity-Ferric reducing anti-oxidant power assay). The nutrient compositions among the cultivars were statistically compared through one-way ANOVA. In 100 g of powdered pumpkin flesh, the nutrient composition was reported as protein content in the range of 32.8-32.9 g, carbohydrate 57.8-57.9 g, lipid content 1.04-6.13 g, crude fibre 2.19-10.94 g, moisture level 8.24%-10.95%, Fe content 4.11-7.76 mg, K content 5,055-8,841 mg, Mg content 96.0-337.02 mg and AO activity 145.1-147.1 mg AAE (Ascorbic acid equivalent) in dry-weight basis. The three varieties of C. maxima have recorded significantly higher nutrient levels (p<0.05) than the C. moschata varieties. The overall nutrient composition was significantly higher in the cultivar type ‘Rajah’, an imported hybrid variety, compared to the other cultivars analysed in the study.
TiO ₂ nanoparticles incorporated CMC-MMT nanocomposite for food packaging applications
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2022-10-28) Perera, A.W.N.D.; Wijesooriya, S.N.; Adassooriya, N.M.
The demand for sustainable food packaging material has increased compared to nonbiodegradable packaging because plastic waste is a serious environmental problem. In this study, different composites of citric acid (CA) crosslinked montmorillonite (MMT) reinforced carboxymethyl cellulose (CMC) films with TiO₂ nanoparticles (NPs) (average size < 20 nm) incorporated to act as antimicrobial agents were investigated for applications in food packaging. Films were fabricated using the solvent casting method with 25% (w/w) CA as the crosslinking agent, and 1%, 3%, and 5% TiO₂ NPs were added to the CMC- MMT nanocomposite with glycerol as a plasticizer. The films were characterized by FTIR, TGA, and PXRD and evaluated for water solubility, moisture content, and moisture uptake ability. The addition of CA and TiO₂ NPs lowered the moisture uptake (MU), water solubility (WS), and moisture content (MC) by reducing polymer network interactions. FTIR analysis confirmed the formation of ester crosslinks between CMC and CA. It was found that MC decreased from 34.3% to 33.3% when the concentration of CA increased and reduced to 29.3% with the addition of 5.0% TiO₂ NPs. The WS was reduced from 67.9% to 66.9% when the amount of CA increased from 15.0% to 25.0% and reduced from 66.7% to 65.2% when the amount of TiO₂ NPs increased from 1.0% to 5.0%. Incorporation of 3% TiO₂ NPs into CMC/MMT/CA25% film remarkably reduced the MU by 21.9% at 97.0% RH and 16.1% at 40.0% RH. According to the thermal analysis, the addition of TiO₂ NPs enhanced the thermal stability of CMC films. The PXRD revealed that TiO₂ NPs and MMT modified the original structure of the CMC by increasing the crystallinity of the films. From the overall results, CA crosslinked TiO₂ NPs incorporated CMC-MMT films were found to exhibit the lowest WS, MU, and MC.
Biodegradable polymer-coated urea granules as a slow-release nitrogen source
(Postgraduate Institute of Science (PGIS), University of Peradeniya, Sri Lanka, 2022-10-28) Dilhan, J.A.M.; Rajapakse, R.M.G.; Adassooriya, N.M.
Urea is the most popular nitrogenous fertilizer due to its relatively low cost and high nitrogen composition. However, approximately 30-50% of urea is only utilized by plants resulting in low nutrient use efficiency (NUE). Several environmental issues originate via the loss of urea throughout various processes, such as direct volatilization, accumulation of urea via runoff, and leaching of urea as nitrates. Controlled-release fertilizers (CRFs) are one of the promising methods to increase NUE and minimize environmental impact. During this study, attempts were made to synthesize biodegradable polymers coated urea granules using cellulose acetate (CA) and polyvinyl alcohol (PVA). 4.5% (v/v) CA solution was prepared in acetone at room temperature with constant stirring at 800 rpm, and this solution was coated on urea granules by the solvent casting method. 3% (v/v) PVA solution was prepared by dissolving PVA in distilled water at 80 °C with constant stirring at 1,000 rpm. Then 30% (w/w) by polymer mass citric acid was added as a crosslinker to the PVA solution after it cooled to room temperature. This solution was sprayed on CA-coated urea granules to synthesize CRFs (UCPC30). Finally, CRFs were dried at 105 °C for 2.5 h for cross-linking. The successful polymer coatings were confirmed by Fourier transform infrared spectroscopy, powder X-ray diffraction, and scanning electron microscopy. The release behaviour of the prepared polymer-coated urea was investigated in the soil medium (pH=5.9), and it was observed that 92% of urea was released from the CRFs in a slow and sustained manner for up to 16 days. Meanwhile, 90% of urea was released from commercial grade within 8 days. The porous hydrogel matrix of the PVA regulates the penetration of urea molecules and extends the release time. Therefore, biodegradable polymer-coated urea granules are ideal candidates for slow-release fertilizer.