英語聽力練習網站:為何腰果不帶殼銷售

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★英語聽力頻道為大家整理的英語聽力練習網站:為何腰果不帶殼銷售,供大家參考。更多閱讀請查看本站英語聽力頻道。
    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.
    為何腰果不帶殼銷售
    吃杏仁和胡桃的部分樂趣來源于敲碎外殼后得到果仁。然而,有些堅果,比如腰果,通常會去殼烤熟銷售。為什么腰果會不帶殼銷售呢?
    腰果和毒葛與毒漆樹同屬一科。與同科其它植物相似,腰果樹含有強烈刺激性化學物質,所以處理和吃掉生腰果,會使那些對化學物質敏感的人皮膚產生瘙癢反應。對某一科某種植物過敏的人,比如對毒葛過敏,很有可能會對同科的其它植物也過敏。
    那當我們吃腰果時為什么沒有反應呢?那是因為刺激物質存在于外殼油脂中,而果仁中卻不含有。所以處理外殼或者吃帶有外殼油脂的腰果時,就會引起(瘙癢)反應。
    這就是為什么腰果不帶殼售賣的原因,但是又為什么要烤熟呢?因為高溫烘烤可以破壞果殼油脂,所以商業(yè)銷售的腰果仁不會造成反應。帶殼的或者在家中去殼并低溫烘烤后的腰果可能仍會受到果殼油脂的污染,所以給生腰果去殼和處理毒葛一樣有趣。