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Binding of Clitoria ternatea L. flower extract with α-amylase simultaneously monitored at two wavelengths using a photon streaming time-resolved fluorescence approach
摘要： The binding of an extract from the flowers of Clitoria ternatea L. to the digestive enzyme α-amylase was investigated. This extract is a mixture of flavonoids, including anthocyanins, and has been previously shown to inhibit the activity this enzyme. This has implications for modulating starch digestion. Since the extract contains a mixture of flavonoids, including anthocyanins, in order to investigate the kinetics, we made use of time-resolved fluorescence to simultaneously monitor two different emission bands emanating from the extract. This measurement was enabled by the use of a “photon streaming” approach and changes in fluorescence lifetime and intensity were used to follow the interaction. A longer wavelength band (655 nm) was ascribed to anthocyanins in the mixture and these were observed to bind at a rate an order of magnitude slower than other flavonoids present in the extract, monitored at a shorter wavelength (485 nm). Changes in the fluorescence emission of the extract upon binding were further assessed by the use of decay associated spectra.
关键词： TCSPC,Butterfly pea,Anthocyanins,Enzyme inhibition,Flavonoids
更新于2025-09-23 15:21:21
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Natural Dyes from Morti?±o (Vaccinium floribundum) as Sensitizers in Solar Cells
摘要： Photovoltaic energy presents environmental advantages; however, these advantages are limited by the cost of manufacturing solar cells and in many cases, scarce or dangerous materials are incorporated. Therefore, the use of natural dyes from morti?o (Vaccinium ?oribundum) as sensitizers in solar cells is proposed. The dyes were extracted by maceration in acidi?ed methanol (HCl, citric acid and tri?uoroacetic acid TFA) and were characterized by High-Performance Liquid Chromatography (HPLC), Thin-Layer Chromatography (TLC) and spectrometric methods (UV-Vis, IR and MS-MALDI). The construction and characterization of cells were in standard conditions. The study con?rms that pigments in morti?o are ?avonoids of the anthocyanidin group as: cyanidin-3-galactoside, and cyanidin-3-arabinoside. The e?ciency of solar cells was between 0.18–0.26%; the extraction with TFA in methanol leads to the best performance. Although they have low power conversion e?ciency, morti?o dyes could be an alternative to arti?cial sensitizers for solar cell technologies because they are harmless and abundant substances.
关键词： morti?o,e?ciency,solar cells,sensitizer,anthocyanins,dye
更新于2025-09-19 17:13:59
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Performance Stability and Optical Properties of Musa Acuminata bracts-based Dye-Sensitized Solar Cell
摘要： The study of stability and optical properties of the dye-sensitized solar cell (DSSC) based extract of Musa Acuminata bracts have been done.Banana flowers extract was used as photoactive material because it contains anthocyanin. This study focuses on the optimization of semiconductor, natural pigment, and the counter electrode.The ZnO coating used spray coating method. Anthocyanin and polyethylene glycol (PEG) coating were conducted using droplet method.Fabrication of plated copper counter electrode was performed using the electrochemical method. PEDOT:PSS electrolyte is coated on the final process after the two electrodes are coupled by inserting between the two electrodes. The highest efficiency reached 6.24x10-2%.
关键词： anthocyanins,droplet method,electrochemical method,DSSC Pt-free,musa acuminata bracts
更新于2025-09-16 10:30:52
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Enhanced Antioxidant Capacity of Fresh Blueberries by Pulsed Light Treatment
摘要： As a novel technology for food safety risk mitigation, pulsed light (PL) has been shown effective in surface decontamination of fresh blueberries in literature. However, little is known about the effects of PL on the antioxidant capacity and quality characteristics of fresh blueberries. Fresh blueberries from a local farm were treated with PL for 30, 60, 90 and 120 s. Results show that PL exposure enhanced the antioxidant activity (ORAC) and total phenolic content of fresh blueberries 50 and 48% respectively, relative to the control. Pulsed light also significantly increased the total anthocyanin contents, which may be due to the upregulation of Phenylalanine Ammonium Lyase (PAL) enzymes. There was no significant difference (P ≤ 0.05) in the soluble solids, pH, titratable acidity, firmness, color and mass of the fresh blueberries within 120 s PL exposure. In conclusion, PL illumination enhanced the antioxidant capacity of fresh blueberries while maintaining other quality characteristics.
关键词： phenolics,phenylalanine ammonium lyase,phytochemical,nonthermal,flavonoids,anthocyanins
更新于2025-09-09 09:28:46