Composition and physicochemical properties of oat starches

Starches from two new oat varieties namely AC Stewart (Avena sativa L.) and NO 753-2 (Avena nuda L.) were isolated and some of their characteristics determined. The total amount of starch lipids (TSL) extracted by acid hydrolysis was 1.60% (w/w) in both starches. The free lipid content (extracted by chloroform-methanol (CM) 2:1 v/v at 25°C) was 0.36 and 0.30% (w/w) in NO 753-2 and AC Stewart starches, respectively. The bound lipid content (extracted by hot n-propanol-water 3:1 v/v from the residue left after CM extraction) was 1.27 and 1.37% (w/w) in NO 753-2 and AC Stewart starches, respectively. The total amylose contents were nearly the same (~23%, w/w) in both starches, of which 14.1 (NO 753-2) and 15.3% (AC Stewart) were complexed by native lipids. The starches differed widely in their degree of swelling, gelatinization transition temperatures and enthalpy, susceptibility towards acid and enzyme hydrolysis, gel strength, paste viscosity, thermal stability and retrogradation characteristics. The results suggest that the extent of interaction of starch chains within the amorphous and crystalline regions of the granule was stronger in NO 753-2 than in AC Stewart

Enzyme-assisted synthesis of structured lipids containing long-chain omega-3 and omega-6 polyunsaturated fatty acids

Lipase-catalyzed acidolysis of borage (Borago officinalis L.) and evening primrose (Oenothera biennis L.) oils with long-chain ω3-polyunsaturated fatty acids (LCω3-PUFA), namely docosahexaenoic acid (DHA) and/or eicosapentaenoic acid (EPA), in organic solvents was studied. Six microbial lipases from Candida antarctica, Mucor miehei, Pseudomonas sp., Aspergillus niger, Candida rugosa and Thermomyces lanuginosus were initially used as biocatalysts for the acidolysis reaction. Among the enzymes tested, an immobilized lipase, Novozym-435 from Candida antarctica showed the highest degree of DHA incorporation (25.8-28.7%, after 24 h) in borage oil (BO) and evening primrose oil (EPO). However, the maximum incorporation of EPA (28.7-30.7%, after 24 h) in both oils was achieved with lipase PS-30 from Pseudomonas sp. In another study, incorporation of EPA+DHA into BO and EPO was carried out by first screening of lipases listed above; lipase PS-30 from Pseudomonas sp. was the most efficient enzyme examined (31.7-32.7% EPA+DHA incorporation, after 24 h). -- Effects of variation of reaction parameters, namely enzyme load, temperature, time course, mole ratio of substrates and type of organic solvents were monitored for the most effective enzymes, those from Candida antarctica and Pseudomonas sp., as the biocatalysts of choice. Incorporation of DHA and/or EPA increased significantly (p ≤ 0.05) with increasing the amount of enzyme. As the incubation time progressed, incorporation of these fatty acids was also increased, similar to that observed when the temperature and mole ratio of substrates increased. The highest DHA (37.4-39.7%) or EPA (37.4-39.9%) incorporation occurred at a mole ratio of 1:3 (oil/ DHA or EPA). However, maximum incorporation of EPA+DHA (54-57.5%) occurred at a mole ratio of 1:2:2 (oil/EPA/DHA) and then remained constant between mole ratios of 1:2:2 and 1:3:3. Among solvents examined, n-hexane served best in giving rise to 25.5-27.4% DHA, 25.2-26.8% EPA and 27.8-33.3% EPA+DHA incorporation in the oils. However, solvent-free reactions also gave satisfactory incorporation of 18.1-20.5% DHA, 18.6-20.4% EPA and 23.4-28.8% EPA+DHA in the oils tested. -- Response surface methodology (RSM) was used to obtain a maximum yield of DHA, EPA and EPA+DHA incorporation while using the minimum amount of enzyme possible. Process parameters studied were the amount of enzyme (100-350 units), reaction temperature (20-60°C) and reaction time (6-30 h). All experiments were carried out according to a face-centred cube design. Under optimum conditions (162-165 units of Candida antarctica enzyme: 43-50°C; 25-27 h), incorporation of DHA was 35.6% in BO and 33.5% in EPO. Optimization of acidolysis of oils with EPA, gave rise to a maximum of 35.4 and 33.9% EPA incorporation in BO and EPO, respectively, at 299-309 units of Pseudomonas sp. enzyme, reaction temperature of 40-44°C and reaction time of 25-27 h. Similarly, maximum incorporation of EPA+DHA in BO (35.5%) and EPO (33.6%) was attained at 278-299 units of Pseudomonas sp enzyme, at 42-43°C after 24-26 h. -- In another study, enzymatically modified oils, produced under optimum reaction conditions, were classified using thin-layer chromatography-flame ionization detection (TLC-FID). The results showed that the content of TAG (85.1-95.1%) was much higher than that of the DAG (2.4-11.2%) and MAG (0.3-9.7%) in the structured lipids so produced. Because free fatty acids were removed by NaOH after the acidolysis reaction, they were not detected by TLC-FID. The products were also separated by TLC and the fatty acid compositions of their corresponding isolated bands analyzed by gas chromatography. Results showed that DHA and/or EPA were mainly located in TAG fractions of enzymatically modified oils (33.2-35.4% DHA; 32.5-33.2% EPA and 33.6-35.5% EPA+DHA in DHA, EPA and EPA+DHA-enriched oils, respectively). The TAG fractions also contained appreciable proportions of γ-linolenic acid (GLA) (11.0-17.1 and 7.5-7.6% in DHA, EPA and EPA+DHA-enriched BO and EPO, respectively). -- Stereospecific analysis was carried out to establish positional distribution of fatty acids in the TAG of DHA, EPA and EPA+DHA-enriched oils. In DHA-enriched BO, DHA was randomly distributed over the three positions of TAG while GLA was mainly esterified at the sn-2 and sn-3 positions. In DHA-enriched EPO, however, DHA and GLA were concentrated in the sn-2 position. In EPA-enriched BO, EPA was randomly distributed over the three positions of TAG, similar to that observed for DHA. In EPA-enriched EPO, however, this fatty acid was mainly located at the primary positions (sn-1 and sn-3) of TAG. In both oils, GLA was preferentially esterified at the sn-2 position. In EPA+DHA-enriched BO, EPA and DHA were mainly esterified at the sn-1 and sn-3 positions of TAG while GLA was mainly located at the sn-2 position. In EPA+DHA-enriched EPO, GLA was mainly located at the sn-2 and sn-3 positions; EPA was preferentially esterified at the sn-1 and sn-3 positions, while DHA was found mainly at the sn-3 position. -- The oxidative stability of enzymatically modified oils as well as their unmodified counterparts was evaluated under Schaal oven conditions at 60°C over a 96 h storage period. Conjugated dienes (CD), 2-thiobarbituric acid reactive substances (TBARS) and headspace volatiles were determined. In addition, proton nuclear magnetic resonance (¹H NMR) spectroscopy was used to monitor relative changes in the proton absorption pattern of the fatty acids of oils during storage. Among the oils examined, enzymatically modified products gave rise to higher CD and TBARS as compared to those of their unmodified counterparts. The main volatile compounds identified in enzymatically modified oils were acetaldehyde, propanal, butanal, pentanal, hexanal, heptanal, octanal and nonanal. However, the main volatile compound found in unmodified oils was hexanal. The contents of propanal and hexanal produced by enzymatically modified oils were significantly higher (p ≤ 0.05) than those produced by their unmodified counterparts. These results suggested that the modified oils were more prone to oxidation than their unmodified counterparts. -- The double bond index (DBI) and methylene bridge index (MBI), represent the number of double bonds and bis allylic methylene bridge positions in PUFA, respectively, were calculated. DBI and MBI of enzymatically modified oils were significantly (p ≤ 0.05) higher than those of their unmodified counterparts. During oxidation of oils, DBI and MBI were decreased. Regression analysis was carried out to correlate various parameters of oxidation (CD, TBARS, hexanal and propanal contents) with DBI and MBI of oils; a negative correlation (r = 0.574-0.975; p ≤ 0.1-0.05) existed between these variables. -- Relative changes of aliphatic to olefinic (Rao) and aliphatic to diallylmethylene (Rad) protons ratios, during oil oxidation, were determined by ¹H NMR spectroscopy. An increase in Rao and Rad values was obtained over the entire storage period. A highly significant correlation (r = 0.930-0.992; p ≤ 0.005) existed between the CD values and changes in Rao and Rad during oxidation of all oils. The correlation coefficient between TBARS and changes in Rao and Rad values was in the range of 0.779 -0.983 (p ≤ 0.05). A high correlation (r = 0.948-0.996; p ≤ 0.005) was found between hexanal content and Rao and Rad of oils. Propanal content was also highly correlated (r = 0.950-0.990; p ≤ 0.005) with Rao and Rad. This suggests that ¹H NMR could be used to simultaneously estimate both primary and secondary oxidation changes in native and enzymatically modified oils

The influence of nano-architectured CeOx supports in RhPd/CeO2 for the catalytic ethanol steam reforming reaction

The ethanol steam reforming (ESR) reaction has been tested over RhPd supported on polycrystalline ceria in comparison to structured supports composed of nanoshaped CeO2 cubes and CeO2 rods tailored toward the production of hydrogen. At 650-700 K the hydrogen yield follows the trend RhPd/CeO(2)cubes >RhPd/CeO2-rods >RhPd/CeO2-polycrystalline, whereas at temperatures higher than 800K the catalytic performance of all samples is similar and close to the thermodynamic equilibrium. The improved performance of RhPd/CeO2-cubes and RhPd/CeO2-rods for ESR at low temperature is mainly ascribed to higher water-gas shift activity and a strong interaction between the bimetallic-oxide support interaction. STEM analysis shows the existence of RhPd alloyed nanoparticles in all samples, with no apparent relationship between ESR performance and RhPd particle size. X-ray diffraction under operating conditions shows metal reorganization on {1 0 0} and {1 1 0} ceria crystallographic planes during catalyst activation and ESR, but not on {1 1 1} ceria crystallographic planes. The RhPd reconstructing and tuned activation over ceria nanocubes and nanorods is considered the main reason for better catalytic activity with respect to conventional catalysts based on polycrystalline ceria. (C) 2015 Elsevier B.V. All rights reserved.Postprint (author's final draft

Visible light-driven H2 production over highly dispersed Ruthenia on Rutile TiO2 nanorods

The immobilization of miniscule quantities of RuO2 (~0.1%) onto one-dimensional (1D) TiO2 nanorods (NRs) allows H2 evolution from water under visible light irradiation. Rod-like rutile TiO2 structures, exposing preferentially (110) surfaces, are shown to be critical for the deposition of RuO2 to enable photocatalytic activity in the visible region. The superior performance is rationalized on the basis of fundamental experimental studies and theoretical calculations, demonstrating that RuO2(110) grown as 1D nanowires on rutile TiO2(110), which occurs only at extremely low loads of RuO2, leads to the formation of a heterointerface that efficiently adsorbs visible light. The surface defects, band gap narrowing, visible photoresponse, and favorable upward band bending at the heterointerface drastically facilitate the transfer and separation of photogenerated charge carriers.Peer ReviewedPostprint (published version

Extraction of Scandium (III) from acidic solutions using organo-phosphoric acid reagents: A comparative study

Comparative and synergistic solvent extraction of Sc(III) using two phosphoric acidic reagents such as di-(2-ethyhexyl) phosphoric acid and 2,4,4,tri-methyl,pentyl-phosphinic acid was investigated. Slope analysis method suggests a cation exchange reaction of Sc(III) with both extractants at a molar ratio of extractant: Sc(III) = 2.5:1 at equilibrium pH< 1.5. The plot of log D vs. log [Extractant] yield the slope (n) value as low as 1.2-1.3 and as high as n=7 at low and high extrcatant concentration level, respectively. Extraction isotherm study predicted the need of 2 stages at A: O=1:4 and A: O=1:3 using 0.1 M D2EHPA and 0.1 M Cyanex 272, respectively. Stripping of Sc (III) was carried out at varied NaOH concentration to ascertain the optimum stripping condition for effective enrichment of metal. The predicted stripping condition (2)-stages with A: O=1:3 and 1:4 for D2EHPA and Cyanex 272, respectively) obtained from Mc-Cabe Thiele plot was further validated by 6-cycles CCS study. An actual leach solution of Mg-Sc alloy bearing 1.0 g/L of Sc (III), 2.5 g/L of Mg and 0.2 M HCl was subjected for selective separation of Sc at the optimum condition. The counter current simulation (CCS) study for both extraction and stripping of actual solution resulted quantitative separation of Sc with ∼12 fold enrichment. The organic phase before and after loading of Sc (III) along with the diluents was characterized by FTIR to ascertain the phase transportation of Sc (III)

Exploring natural resources for sustainable management of ecosystems future challenges for control and management of Xyleborus fornicatus eichh. (Coleoptera Scolytidae), the shot-hole borer of tea in Sri Lanka

In view of the highly diverse genetic base of the seedling tea plants, though cultivated as a monocrop,along with shade trees and surrounding forests, provided a reasonably stable ecosystem then. Withthe introduction of high yielding vegetatively propagated tea during 1950's, a significant change in thedistribution and population densities of pests has been taken place. Shot-hole borer is one such pestand since then it has become the most serious and damaging pest of tea in Sri Lanka. Control hasbeen a difficult task as a result of its' wide distribution from near sea level up to 1500m amsl and theconcealed habit virtually protected from parasites and predators. Biological control usingentomopathogenic fungus, Beauvaria bassiana Vuillemin (Balsomo ) is being viewed as anenvironmentally friendly alternative to chemical control in the light of growing concern on the usage of pesticides and since oflate, the detection of pesticide residues in made tea. Preliminary investigationswere carried out with a view to find out a suitable local strain/s of the fungus for use against this pest.Laboratory studies have shown that strains of this fungus isolated from a tea garden in Talawakelle(Nuwera Eliya District) and a home garden in Welimada (Badulla District) are highly pathogenic toshot-hole borer imparting more than 90% mortality. A potential exists for using the locally availablenatural resources like entomopathogenic fungi for the management of key pests in a compatible andecologically acceptable manner. This forms the basis for Integrated Pest Management (lPM) approachof key pests. These efforts will promote and ensure the sustainable development of the tea ccosyst;m

Assessing soil erosion hazards using land-use change and landslide frequency ratio method: A case study of Sabaragamuwa province, Sri Lanka

© 2020 by the authors. This study aims to identify the vulnerable landscape areas using landslide frequency ratio and land-use change associated soil erosion hazard by employing geo-informatics techniques and the revised universal soil loss equation (RUSLE) model. Required datasets were collected from multiple sources, such as multi-temporal Landsat images, soil data, rainfall data, land-use land-cover (LULC) maps, topographic maps, and details of the past landslide incidents. Landsat satellite images from 2000, 2010, and 2019 were used to assess the land-use change. Geospatial input data on rainfall, soil type, terrain characteristics, and land cover were employed for soil erosion hazard classification and mapping. Landscape vulnerability was examined on the basis of land-use change, erosion hazard class, and landslide frequency ratio. Then the erodible hazard areas were identified and prioritized at the scale of river distribution zones. The image analysis of Sabaragamuwa Province in Sri Lanka from 2000 to 2019 indicates a significant increase in cropping areas (17.96%) and urban areas (3.07%), whereas less dense forest and dense forest coverage are significantly reduced (14.18% and 6.46%, respectively). The average annual soil erosion rate increased from 14.56 to 15.53 t/ha/year from year 2000 to 2019. The highest landslide frequency ratios are found in the less dense forest area and cropping area, and were identified as more prone to future landslides. The river distribution zones Athtanagalu Oya (A-2), Kalani River-south (A-3), and Kalani River-north (A-9), were identified as immediate priority areas for soil conservation

Quality of Municipal Solid Waste Compost Produced in Sri Lanka

Rapid urbanization has made solid waste management a serious problem for local authorities in Sri Lanka. The compost production with Municipal Solid Waste (MSW) and good quality assurance of compost produced by such is crucial in utilizing these problematic wastes as an agriculturally important product. This study was focused on evaluating the overall quality of Municipal Solid Waste Compost (MSWC) in Sri Lanka. Primary and secondary data of compost physicochemical and biological characters covering 45 composting sites representing 88% of functioning Pilisaru composting sites of SL were used for the study. A large set of secondary data on MSWC quality parameters were collected from well reputed government laboratories with the approval of the Central Environmental Authority (CEA). Inadequate data were analyzed. Box plots were developed using data on color, moisture, odor, sand content, particle size, PH, conductivity, organic carbon, C:N ratio, total nitrogen, Phosphorus, Potassium, Magnesium, Calcium, Arsenic, Cadmium, Chromium, Copper, Lead, Mercury, Nickel, Zinc, Fecal coliform and Salmonella in MSWC samples. Central tendency, data distribution and deviations of each parameter were identified after eliminating outliers. The conformity percentage to Sri Lankan Standards (SLS) and Bureau of Indian Standards (BIS) were calculated. The heavy metal contents were compared with Portugal, France and Italy standards for MSWC in addition to SLS and BIS. Normal probability plots of the residual were designed in order to identify the data distribution pattern. Spatial variability of data in each individual parameter was analyzed in district basis. Mean and median value of moisture content, sand content, MgO, Hg content and fecal coli form was not conformant with SLS and BIS. Although the mean value of particle size conformant with BIS it has exceeded the levels in SLS. Cd, Cu, Zn and Ni contents showed 100% conformity with SLS, BIS, France, Italy and Portugal standards. Cr and Pb contents showed more than 90% conformity to all the standards. Colour, odour, pH, organic carbon, total N, Ca, Cd, Cr, Cu, Pb, Ni, Zn and salmonella resulted in more than 75% conformity to SLS. Sand content is the most deviated parameter from SLS. Significant special variability was reported for particular districts with regard to sand content, pH, total N, P2O5 and K2O. Thus, MSWC quality in SL could be improved via giving the emphasis on the parameters which are not conformant with the standards.Keywords: Municipal Solid Waste Compost (MSWC), Sri Lankan Standard (SLS), Bureau of Indian Standard (BIS

A Review on Assessing and Mapping Soil Erosion Hazard Using Geo-Informatics Technology for Farming System Management

Soil erosion is a severe threat to food production systems globally. Food production in farming systems decreases with increasing soil erosion hazards. This review article focuses on geo-informatics applications for identifying, assessing and predicting erosion hazards for sustainable farming system development. Several researchers have used a variety of quantitative and qualitative methods with erosion models, integrating geo-informatics techniques for spatial interpretations to address soil erosion and land degradation issues. The review identified different geo-informatics methods of erosion hazard assessment and highlighted some research gaps that can provide a basis to develop appropriate novel methodologies for future studies. It was found that rainfall variation and land-use changes significantly contribute to soil erosion hazards. There is a need for more research on the spatial and temporal pattern of water erosion with rainfall variation, innovative techniques and strategies for landscape evaluation to improve the environmental conditions in a sustainable manner. Examining water erosion and predicting erosion hazards for future climate scenarios could also be approached with emerging algorithms in geo-informatics and spatiotemporal analysis at higher spatial resolutions. Further, geo-informatics can be applied with real-time data for continuous monitoring and evaluation of erosion hazards to risk reduction and prevent the damages in farming systems.</jats:p