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Managing Scarce Water Resources in Irrigated Agri-Food Systems of Central Asia Two Case Studies Full text
2017
Irrigated agriculture is the backbone of Central Asian economies. Therefore, efficient irrigation water management is of crucial importance to the sustainable crop production in the region. Presented here are two studies aiming to improve agricultural water productivity â?? ET-based irrigation scheduling in Uzbekistan; and valuation of ecosystem services in Kazakhstan. The ET-based irrigation scheduling method has potential to replace subjective daily water management decisions at Water Users Association level with crop water demand-based decisions to improve water-use efficiency. Results from a two year study show that there can be a 32-35% saving of water when irrigation is applied using the ET-based scheduling method. The pilot plots are representative of 38% of irrigated area in Fergana Valley (241,407ha) and 50% in Khorezm (137,500ha) area. If this methodology is widely adopted, large amounts of water can be saved which can be diverted for other purposes. Flood irrigation of cotton is practiced on 128,000ha in the Bugunski Reservoir watershed of Kazakhstan. This practice is unsustainable due to seasonal unavailability in water supply and depletion of river discharges that were historically important at maintaining water levels downstream in nearby wetlands and the Aral Sea. Farmer surveys were used along with RIOS and SWAT modeling to evaluate alternative irrigation practices and cropping systems that can conserve water from the Bugunski Reservoir while maintaining farmer incomes. Simulations show significant reductions in irrigation water demand in the alternative scenario relative to the baseline scenario. Under baseline flood irrigation of cotton, annual irrigation demand was 928 MCM/yr averaged over the 32 year climatic record simulated. Irrigation demand decreased by 38% to 573 MCM/yr when 40,439ha of flood irrigated cotton was converted to drip irrigated cotton, sprinkler irrigated alfalfa and drip irrigated grapes. This represents a savings of 355 MCM/yr in water extracted from irrigation canals and groundwater wells | Vinay Nangia. (7/11/2016). Managing Scarce Water Resources in Irrigated Agri-Food Systems of Central Asia Two Case Studies. Phoenix, United States: American Society of Agronomy.
Show more [+] Less [-]A feasibility study on green biorefinery of high lignin content agro-food industry waste through supercritical water treatment Full text
2021
Adamovic, Tijana | Tarasov, Dmitry | Demirkaya, Emre | Balakshin, Mikhail | Cocero, Maria José
This work discusses hydrolysis of defatted grape in supercritical water (SCW) at 380 °C and 260 bar from 0.18 s to 1 s focusing attention to sugars recovery in the liquid phase of the product and detailed characterization of remaining solid phase enriched in polyaromatics (e.g. lignin, flavonoids, etc.). After the longest reaction time of 1 s, 56% of carbohydrates could be recovered in the liquid phase, as a result of carbohydrate hydrolysis. The high content of insoluble lignin in biomass (36%), acts as a mass transfer limitation and presents an important feature in the hydrolysis process, slowing down the conversion of carbohydrate fraction, as after the maximum time of 1s, 10% of carbohydrates still remained in the solid phase. Milled wood lignin, extracted from biomass and dioxane extract from the solid phase were characterized in order to understand the main structural changes during the SCW hydrolysis process. Dioxane (80%) extraction of solids produces a very complex mixture of lipophilic extractives, flavonoids and lignin with a certain amount of chemically linked carbohydrates. 2D NMR analysis of dioxane extract shows remarkably subtle changes in the amounts of main lignin moieties (β-O-4′, β-β’ (resinol) and β-5 (phenylcoumaran)). This subtle change of the main lignin structures is an important feature in the further valorisation of this sulfur-free lignin residue.
Show more [+] Less [-]High efficient solid-phase microextraction based on a covalent organic framework for determination of trifluralin and chlorpyrifos in water and food samples by GC-CD-IMS Full text
2022
Tabibi, Alireza | Jafari, Mohammad T.
Novel porous covalent organic framework (COF) based on condensation reaction between cyanuric chloride, 4,4′-ethylendianiline, and 3,4,9,10-perylenetetracarboxylic dianhydride was synthesized via sealed tube condition. The results COF was used as a new adsorbent for solid-phase microextraction (SPME) for extracting trifluralin and chlorpyrifos from vegetables, fruit samples, and wastewater. Gas chromatograph with a corona discharge-ion mobility spectrometer as the detector was also used for analyzing the target analytes. Some parameters that affected the extraction, such as stirring rate, time and temperature of extraction and pH were investigated, exhaustively. The detection limits were 0.13, and 0.15 µg/L and the linear ranges of 0.45–20 and 0.50–25 µg/L with a linearity coefficient of 0.9965 and 0.9987 were also obtained for trifluralin and chlorpyrifos, respectively. The method was applied successfully to analyze some real samples of cucumber, carrot, grape, and agriculture wastewater, and the results showed a relative recovery in the range of 87% to 110%.
Show more [+] Less [-]An improved surface enhanced Raman spectroscopic method using a paper-based grape skin-gold nanoparticles/graphene oxide substrate for detection of rhodamine 6G in water and food Full text
2022
Sridhar, Kandi | Inbaraj, Baskaran Stephen | Chen, Bing-Huei
Organic toxins are persistent chemicals of global concern capable of accumulating in environment and food. Surface enhanced Raman spectroscopy (SERS) is a promising technique that facilitates onsite detection of organic toxins. However, the fabrication of a SERS substrate is complicated and difficult to provide flexibility, fastness and cost-effectiveness. This study aims to develop a paper-based SERS method using grape skin-gold nanoparticles/graphene oxide (GE-AuNPs/GO) as SERS substrate and evaluate its efficiency with rhodamine 6G (Rh6G) as a model organic toxin and a real water and food contaminant. GE-AuNPs synthesized by green method using grape skin waste extract and GE-AuNPs/GO showed a surface plasmon resonance at 536 and 539 nm, particle size 18.6 and 19.5 nm, and zeta potential −44.6 and −59.7 mV, respectively. Paper-based SERS substrates were prepared by coating a hydrophobic thin-film of 30% polydimethylsiloxane solution in hexane on Whatman no. 1 filter paper, followed by drop-casting GE-AuNPs or GE-AuNPs/GO and drying. The SERS signals of Rh6G showed an enhancement factor of 5.8 × 10⁴ for GE-AuNPs and 1.92 × 10⁹ for GE-AuNPs/GO, implying that a combination of electromagnetic surface plasmon, charge transfer and molecular resonances may be responsible for a higher enhancement of signal by the latter. A low detection limit of 7.33 × 10⁻¹¹ M in the linear range of 10⁻¹¹–10⁻⁵ M was obtained for GE-AuNPs/GO, while the relative standard deviation of repeatability and reproducibility was 9.6 and 12.6%, respectively. Paper-based GE-AuNPs/GO SERS substrate was highly stable as <20% loss in efficiency was shown over a 60-day storage period. Application to real samples showed a high recovery of Rh6G from tap water (93.9–100.8%) as well as food samples such as red chilli powder (91.0–95.4%), red glutinous rice ball (96.6–98.3%) and tomato ketchup (98.9–102.3%) after QuEChERS extraction. Collectively, the developed paper-based GE-AuNPs/GO can be a potential substrate for sensitive onsite detection of rhodamine 6G by SERS method.
Show more [+] Less [-]Degradation kinetics of encapsulated grape skin phenolics and micronized grape skins in various water activity environments and criteria to develop wide-ranging and tailor-made food applications Full text
2017
Lavelli, Vera | Sri Harsha, Pedapati S.C. | Laureati, Monica | Pagliarini, Ella
Micronized grape skin powder (GS) and maltodextrin-encapsulated grape skin phenolics (eGSP) were recovered from winemaking byproducts as potential food ingredients. Hygroscopicity was higher in eGSP than in GS. Both eGSP and GS had intense color and less fermented odor than the wet GS. Phenolic content, antioxidant activity and inhibitory effectiveness towards enzymes related to hyperglycemia damage were ~ double in eGSP than in GS. During storage, the rate of phenolic degradation diminished with decreasing aw from 0.75 to 0.11. Anthocyanins and proanthocyanidins were less stable than monomeric flavanols and flavonols. The rate of decrease in antioxidant activity was lower compared to the extent of phenolic degradation. At aw 0.11 no degradation was observed in eGSP, while anthocyanin and proanthocyanidin contents slightly decreased in GS (k∗103 in the range 0.69–2.94d−1). Criteria for GS and eGSP storage were defined in relation to their final uses.The conversion of winemaking by products into value added products is considered the unique strategy to overcome the cost of not recycling, including waste disposal and decontamination of affected areas. As winemaking is a seasonal activity, long-term stability of recovered byproducts is needed for their further utilization. GS and eGSP represent potential value-added food ingredients for wide-ranging applications (antioxidant, colorant, phenolic sources) and tailor-made functionalities (inhibitors of enzymes related to hyperglycemia). The results obtained led to the definition of criteria for GS and eGSP storage, which depend on their final use in foods, as illustrated by two discussed scenarios.
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