Once a piece of fruit or a vegetable is picked, it starts to go bad. One common way to slow or stop that is to remove water from the foods. The process—dehydration (脱水)—typically uses heat, which can destroy their nutrients (营养). Now, researchers have come up with a new way, and it may help make dried fruit and vegetables more nutritious.
A common way to dry fruit and vegetables is to blow hot air across them. “But there’s another way to get air moving, and it doesn’t need a fan or heat,” says Kamran Iranshahi. He’s a mechanical engineer. Called “ionic wind (离子风)”, this technique had never seemed ready for being used widely. So Iranshahi’s team began improving the process.
In earlier research, the fruit and vegetables to be dried rested on a metal plate. As airflow never reached the underside of the foods, those pieces dried rather slowly. Iranshahi’s team has just replaced the plate with a metal mesh (网孔). That seemingly small change appears to have made a big difference. Using it, the team has not only cut the drying time, but in the latest test it also has dropped the energy use by more than 85 percent!
“People considered the hot air drying process as good enough for many years. But now, more and more people are worried about the health of their foods, so the popularity of drying foods with air moved by a fan or heat has waned,” says Vijaya Raghavan. He’s a mechanical engineer at McGill University in Montreal, Canada. “This team’s impressive invention”, he says, “may now make it easier to offer healthy and tasty dried foods.”
The new version of ionic wind could be more energy efficient, Iranshahi says. So far, few studies have tested the nutrient content of produce dried with ionic wind. However, Iranshahi notes, the new technique should destroy fewer nutrients than heat-based methods, and his team will focus on that in future studies.
【小题1】What can we say about the work of Iranshahi’s team?| A．It causes a waste of resources. |
| B．It saves much time and energy. |
| C．It is costly for using high technology. |
| D．It changes the previous design completely. |
| A．Worked. | B．Begun. | C．Weakened. | D．Grown. |
| A．Satisfied. | B．Worried. | C．Doubtful. | D．Surprised. |
| A．Iranshahi is proud of his team’s achievements. |
| B．Heat-based methods of drying foods will be given up. |
| C．Iranshahi’s team will keep working on getting healthy dried foods. |
| D．The drying method with ionic wind has attracted public attention. |
