英语听力文摘 English Digest 702 为何腰果不带壳销售？（在线收听）

Why Cashews Aren’t Sold In The Shell

Part of the fun of eating almonds or pecans is cracking the shell and getting the nut. But, some nuts, like cashews, are almost always sold shelled and roasted. Why aren’t cashews sold in the shell?

Cashews are in the same family as poison ivy and poison sumac. Like the others in this family, the cashew plant contains powerful chemical irritants, so handling and eating raw cashews will cause the familiar itchy skin reaction in people sensitive to the chemicals. People who are sensitive to one plant in the family, for example poison ivy, are likely to be sensitive to others.

Why don’t we get a reaction when we eat cashew nuts, then? The irritants are found in the shell oil, but not in the nuts themselves. Handling the shell or eating a nut with shell oil on it can cause the reaction.

This is why they’re sold shelled, but why are they roasted? Roasting at high temperature destroys the shell oil, so commercially sold nuts will not trigger a reaction. But, cashew nuts that are still in the shell or that are shelled and roasted at home at lower temperatures may be contaminated with the oil, so, shelling raw cashews is about as much fun as handling poison ivy.

为什么腰果不带壳出售

吃杏仁或山核桃的乐趣之一是敲开果壳，得到坚果。但是，一些坚果，如腰果，几乎总是脱壳和烘烤出售。为什么腰果不带壳卖？

腰果与毒常春藤和毒漆树同属一个家族。像这个家族中的其他人一样，腰果植物含有强大的化学刺激物，因此处理和食用生腰果会导致对化学物质敏感的人产生熟悉的皮肤瘙痒反应。对家族中的一种植物敏感的人，例如毒常春藤，可能对其他植物敏感。

那么，当我们吃腰果时，为什么不产生反应呢？刺激性物质存在于壳油中，但不存在于坚果本身。处理外壳或食用带有壳油的坚果可能会引起反应。

这就是为什么他们卖的是带壳的，但为什么要烤？高温烘烤会破坏果壳油，因此商业销售的坚果不会引发反应。但是，仍在壳中的腰果或在家中低温烘烤的腰果可能会被油污染，因此，剥生腰果和处理毒常春藤一样有趣。