Why Doesn’t Honey Spoil?
If you haven’t cleaned out your refrigerator in a while, there might be a nasty surprise waiting for you. There, in a forgotten piece of Tupperware, lurks the ravioli you didn’t finish three weeks ago. Opening the lid with curiosity and fear, you’re confronted by a blue-green mess that only vaguely resembles pasta.
The lesson here seems to be that even when a jar or container is resealed and refrigerated, the food inside inevitably succumbs to a moldy end.
Actually, it depends on the food. For instance, when’s the last time you noticed that your honey had gone bad? Apparently, a jar of honey that’s been opened and resealed can stay on the shelf for years without going bad. Archaeologists have even found ancient jars with unspoiled honey inside.
So What’s The Secret To This Longevity?
Most food ferments when bacteria living in it eat sugars and nutrients in the food. The bacteria subsequently produce waste in the form of acids and other chemicals that affect the appearance, smell, and taste of the food. In other words, bacterial waste is what causes food to rot and appear moldy.
But like most life forms, bacteria need water to thrive. While many foods contain a good deal of water, honey contains almost none. What little water exists in honey binds to its sugars and enzymes, leaving little for bacterial growth. Unsealed, honey will attract water from the air and eventually ferment. But sealed, honey lasts for ages.
Of course, even sealed honey will eventually crystallize and turn hard, but this doesn’t mean it’s spoiled. In fact, even years later, it’s as good as new.
為什么蜂蜜不會變壞?
如果你有一段時間沒有清理過你的冰箱了,那么里面臟亂的景象會讓你大吃一驚。被遺忘的特百惠保鮮盒里放著三天前你沒有吃完的餃子。你好奇又害怕地打開蓋子,看到的是一團藍綠色的臟亂的東西,看起來依稀有點像意大利面。
這似乎可以告訴我們,即使一個打開的罐子或容器被再次密封并且冷藏,里面的食物都會不可避免地會發(fā)霉。
實際上,會不會發(fā)霉取決于食物本身。例如,你最近一次發(fā)現(xiàn)你的蜂蜜變壞是什么時候?很明顯,一罐打開過又重新密封的蜂蜜可以保存好幾年而且不變質(zhì)。考古學(xué)家們甚至發(fā)現(xiàn)古代罐子里裝的蜂蜜仍未變質(zhì)。
那蜂蜜的保質(zhì)期能長期保存的秘密是什么呢?
大部分食物發(fā)酵是因為有細菌以這些食物的糖分和其它營養(yǎng)成分為食。接下來細菌代謝產(chǎn)生的廢物會以酸和其他化學(xué)物質(zhì)的方式存在并且影響食物的外觀,氣味和味道。換句話說,細菌的代謝物正是使食物腐爛和外觀發(fā)霉的原因。
但是和許多生物一樣,細菌需要水來繁殖。很多食物都含有大量水分,但是蜂蜜卻幾乎不含水分。蜂蜜中僅有的水分和糖分與酶結(jié)合在一起,幾乎沒水分提供給細菌生長。如果不被密封,蜂蜜會吸收空氣中的水分,最后發(fā)酵。但是若密封起來,蜂蜜可保存好幾年。
當然,即使是密封的蜂蜜最后也會結(jié)晶和變硬,但是這不代表變壞。實際上,即使數(shù)年以后,蜂蜜仍舊新鮮如初。