#Density of sugar portable#
This feature highlights their great potential for powering a variety of portable electronic devices in the near future 5, 7, 8. Compared with microbial fuel cells, EFCs usually generate much higher power density in terms of mW cm −2. Inspired by living cells that can utilize complex organic compounds, for example, starch and glycogen) as stored energy sources, sugar-powered EFCs represent the next generation of biodegradable, highly safe biobatteries. The widespread use of metal-catalysed batteries also raises many concerns, primarily related to safety, toxic metal pollution and the availability of costly, limited, irreplaceable or rare metal resources.Įnzymatic fuel cells (EFCs) are emerging electrobiochemical devices that directly convert chemical energy from a variety of fuels into electricity using low-cost biocatalyst enzymes 3, 4, 5, 6. The energy-storage density of a typical lithium-ion battery is ~0.54 MJ kg −1 (that is, 150 Wh kg −1). The rechargeable lithium-ion battery is often the system of choice because it offers a high energy density, has a flexible and light-weight design and has a longer lifespan than comparable battery technologies 1, 2. The rapidly growing demand for powering portable electronic devices is driving the development of better batteries with features such as enhanced energy-storage densities, high levels of safety, fast rechargeability, biodegradability and small environmental footprints 1. Sugar-powered biobatteries could serve as next-generation green power sources, particularly for portable electronics. Enzymatic fuel cells containing a 15% (wt/v) maltodextrin solution have an energy-storage density of 596 Ah kg −1, which is one order of magnitude higher than that of lithium-ion batteries. This enzymatic fuel cell is based on non-immobilized enzymes that exhibit a maximum power output of 0.8 mW cm −2 and a maximum current density of 6 mA cm −2, which are far higher than the values for systems based on immobilized enzymes. Here we show that nearly 24 electrons per glucose unit of maltodextrin can be produced through a synthetic catabolic pathway that comprises 13 enzymes in an air-breathing enzymatic fuel cell. The incomplete oxidation of sugars mediated by one or a few enzymes in enzymatic fuel cells suffers from low energy densities and slow reaction rates. The nutrient density of foods, paired with a comprehensive program of consumer education, can become the foundation of dietary recommendations and guidelines.High-energy-density, green, safe batteries are highly desirable for meeting the rapidly growing needs of portable electronics. Higher NRF9.3 scores were associated with lower energy density and more nutrient-rich diets. The final NRF9.3 index was based on 9 beneficial nutrients (protein fiber vitamins A, C, and E calcium iron potassium and magnesium) and on 3 nutrients to limit (saturated fat, added sugar, and sodium). Formulas based on sums and means performed better than those based on ratios. Models based on 100 kcal and serving sizes performed better than those based on 100 g. HEI values were calculated for participants in the 1999-2002 NHANES. Second, NRF model performance was repeatedly tested against the Healthy Eating Index (HEI), an independent measure of a healthy diet. First, the NRF models included nutrients to encourage as well as nutrients to limit.
These rigorous scientific standards were applied to the development of the Nutrient-Rich Foods (NRF) family of nutrient profile models. For maximum effectiveness, nutrient profile models need to be transparent, based on publicly accessible nutrient composition data, and validated against independent measures of a healthy diet. Nutrient profile models calculate the content of key nutrients per 100 g, 100 kcal, or per serving size of food.
Foods that supply relatively more nutrients than calories are defined as nutrient dense. Nutrient profiling is the technique of rating or classifying foods on the basis of their nutritional value.
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