SSS 2011-09-01
时间：2019-01-08 作者：英语课 分类：Scientific American(九)月
英语课
This is Scientific American’s 60-Second Science. I’m Cynthia Graber. This will just take a minute.
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.
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.
Thanks for the minute. For Scientific American’s 60-Second Science, I’m Cynthia Graber.