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托福听力练习-科学美国人60秒:超高压灭菌

2017-04-20 17:41:15来源：科学美国人60秒

点击查看>>科学美国人60秒音频：超高压灭菌

　　科学美国人60秒听力练习：超高压灭菌

　　科学美国人60秒英文文本

　　Pasteurization makes food safe by heating microbes to death. But the high temperatures can destroy some nutrients too. A possible alternative? Ultrahigh pressure. Which may also actually increase concentrations of some nutrients, at least in tropical and subtropical fruit. That’s according to research presented at the national meeting of the American Chemical Society in Denver. [Carmen Hernandez-Brenes et al, High hydrostatic pressure processing as a strategy to increase carotenoid contents of tropical fruits]

　　In what’s called Pascalization, food is placed in a vessel, which is force-filled with water. The contents experience extreme pressures of 40,000 to 80,000 pounds per square inch. As a comparison, pressures three miles below the ocean surface are less than 7,000 pounds per square inch. The vessel’s pressure conditions kill bacteria, viruses and molds.

　　Researchers tried Pascalization on the pulp of avocados, papayas and mangos. They measured the levels of carotenoids, an important group of antioxidants. Carotenoids in the avocado and papaya increased overall by about 50 percent, with some individual carotenoids rising more than 500 percent. The mango mysteriously remained unchanged.

　　The researchers next hope to find out exactly how the high pressures are inducing the synthesis of more carotenoids. Pascalization may give food scientists plenty to chew over.

　　—Cynthia Graber

　　中文翻译请点击下一页

本文关键字: 托福听力 科学美国人60秒

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