Caffeine is known to influence the absorbance spectrum of anthocyanin dyes. Such dyes are often used as sensitizers in dye-sensitized solar cells (DSSCs). Natural dyes, like anthocyanins, yield only small DSSC efficiencies, but are of high interest since they are usually non-toxic and inexpensive. Here we report on the influence of copigmentation of anthocyanins, taken from commercially available tea, with caffeine. In this way, the efficiencies were increased for measurements with a solar simulator as well as with ambient light. In addition, the well-known pH dependence of the efficiency of DSSCs dyed with anthocyanins was shifted-while a pH value of 1-2 was ideal for pure anthocyanins used as dyes, a higher pH value of 2-3 was sufficient to reach the maximum efficiencies for caffeine-copigmented dyes. This means that instead of reducing the pH value by adding an acid, adding caffeine can also be used to increase the efficiency of DSSCs prepared with anthocyanins. Finally, a comparison of several literature sources dealing with anthocyanin-based DSSCs allows for evaluation of our results with respect to the work of other groups.
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http://dx.doi.org/10.3390/ma12172692 | DOI Listing |
Sci Rep
December 2024
Department of Scientific Research, The British Museum, Great Russell Street, London, WC1B 3DG, UK.
Various natural dye sources have been historically used and are still used today to decorate Pacific barkcloth. The identification of these natural dyes is a challenging task due to their molecular complexity and the scarcity of scientific investigations. In this study, barkcloth samples collected in Tahiti and dyed using local plants, including fruits of Thespesia populnea (L.
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December 2024
Center for High Technology Research and Development, Vietnam Academy of Science and Technology, Cau Giay, Hanoi, Vietnam.
Objectives: In this study, the impacts of various processing parameters on the quality and consumer satisfaction of dragon fruit beverages were investigated in order to establish an informative framework for the manufacturing of commercial dragon fruit beverages, focusing on health benefits and safety for consumers, and sensory appeal of the products.
Methods: This study employed various analytical methods to quantify some important phytochemical compounds in dragon fruit juice such as total and reducing sugars, vitamin C, betacyanins, anthocyanins, polyphenol, and so forth. This study also employed the Box-Behnken response surface experimental design to optimize various processing parameters for quality and consumer satisfaction, which include enzymatic pectin hydrolysis parameters and formulation for dragon fruit energy drink.
Food Res Int
November 2024
Department of Food Science and Nutrition, School of Food Engineering, Universidade Estadual de Campinas (UNICAMP), 13083-862 Campinas, SP, Brazil; Department of Food Science and Nutrition, Faculty of Food Engineering, Universidade Estadual de Campinas (UNICAMP), 13083-862 Campinas, SP, Brazil. Electronic address:
Considering the growing interest for safer, environmentally friendly and healthier products, the search for natural colorants to replace their synthetic has been raised. This is particularly challenging for the rare and usually unstable bluish coloring substances. This comprehensive review describes several bluish pigments which can be obtained from natural sources (plants and mostly microorganisms), covering less known molecules to well established compounds (although no focus is given for anthocyanins).
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November 2024
Department of Food Preservation, Faculty of Food and Biochemical Technology, University of Chemistry and Technology in Prague, Technická 5, Dejvice, 166 28 Prague, Czech Republic.
Anthocyanins are flavonoid substances of plant origin with potential antioxidant effects. Because of their intense colors, they are used as natural dyes in food. However, their stability in food matrices is limited.
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November 2024
Department of Physics, Bangalore University, Bengaluru, India.
The present study focused on extracting the anthocyanin dyes in ethanol, acidic ethanol, methanol, and acidic methanol solvents from Nerium oleander flowers by a simple maceration extraction process. FTIR spectroscopy and vibrational studies have confirmed the existence of polyphenolic groups in 2-phenyl chromenylium (anthocyanin) dyes. The optoelectronic results show the least direct bandgap (2.
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