Scientists have known for decades that coffee beans contain oil. Mohapatra and c

游客2024-05-29  15

问题 Scientists have known for decades that coffee beans contain oil. Mohapatra and colleagues, however, were the first to analyze coffee grounds.
     Used grounds usually end up in landfills, though gardeners sometimes use them as a kind of fertilizer. The scientists collected used grounds from Starbucks, which gives bags of grounds away as part of the company’s "Grounds for your garden" program.  
     To prepare the grounds for analysis, the team first dried them in an oven. They mixed the resulting powder with a combination of solvents (溶剂) that caused the oil to separate from the solution. They extracted the oil, saving the solvents for the next round of processing. The remains could still be used as compost, ethanol feedstock, and fuel pellets.
     "We’re not wasting anything, " Mohapatra told Discovery News. "It’s a recycling process."  
     The study showed that used grounds contain about 15 percent oil by weight, depending on the type of coffee. That’s not too far off the proportions in soybean, rapeseed, and palm oils, which are also used as sources for bio-diesel. And coffee oil is more stable than these other sources because of its high antioxidant content, found the study, which appeared in December in the American Chemical Society’s Journal of Agricultural and Food Chemistry.
     Around the world, growers produce more than 16 billion pounds of coffee each year, according to the U.S. Department of Agriculture. The scientists estimate that spent grounds could add 340 million gallons of bio-diesel to the global fuel supply.
     Mohapatra pictures a streamlined coffee recycling system, in which the same trucks that deliver beans to Starbucks could pick up the brewed waste and head to a bio-diesel plant. The plant would be close by, to save on transportation costs and emissions.
     Coffee grounds appear to produce high-quality oil, granted Robert McCormick, an engineer at The National Renewable Energy Laboratory in Golden, Colorado. But, he said, coffee probably won’t be a practical solution to the world’s energy needs.
     For one thing, the country’s main sources of bio-diesel-cooking oil and animal fat-are 100 percent oil, compared to coffee’s 15 percent. And even when a cafe brews a large amount of coffee, relatively few grounds are left behind. It takes 50 gallons of spent grounds to produce just 1 gallon of oil, Mohapatra said.
     Still, McCormick commends the researchers for thinking outside the box about the world’s energy issues.
     "Anything that takes a waste product and makes a fuel out of it is really a positive," he said. "This is pretty cool. "  [br] By saying "thinking outside the box", McCormick wants to show his______towards the researchers.

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答案 respect/appreciation

解析 倒数第2段中的commend及末段中的positive和cool等词可知道McCormick对研究人员的成果怀有敬意或赞赏之情,因此本题答案可以是respect,appreciation或其他表示相同情绪的名词。
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