如今,许多市售的馒头、花卷、包子、粉丝、银耳和其它水浸食品,色泽洁白,感官性状良好,这是为什么呢?原来这是不法商贩在制作工艺中添加了一种叫做吊白块的食品增白剂。吊白块的化学名字叫甲醛合亚硫酸钠,它在食品加工过程中分解为二氧化硫和甲醛。亚硫酸钠在食品加工中具有还原漂白作用,而使食品增白。而五万分之一的甲醛就具有防腐作用。故许多水发食品可售数日而无变质迹象,既 Nowadays, many commercially-available steamed bread, buns, buns, fans, white fungus and other water-based foods are white in color with good organoleptic properties. Why is it that the unscrupulous trader added a process called " Food whitening agent. Sliver white chemical name of formaldehyde sodium sulfite, which in food processing is decomposed into sulfur dioxide and formaldehyde. Sodium sulfite in the food processing with the role of reducing bleaching, leaving food whitening. The one-fifth of formaldehyde has a preservative effect. Therefore, many water-based food can be sold for a few days without signs of deterioration, both