The chemistry of cookies - Stephanie Warren

饼干里的化学 - Stephanie Warren

翻译人员: Xue Mei 校对人员: Bighead Ge

In a time-lapse video, it looks like a monster coming alive.

在慢镜头里

似乎一头野兽正在苏醒

For a moment, it sits there innocuously.

刚开始，它只是无害的坐在那儿

Then, ripples move across its surface.

然后，表面开始有了动静

It bulges outwards, bursting with weird boils.

它迅速膨胀

冒出许多奇怪的气泡

It triples in volume.

它体积一下膨胀两倍

Its color darkens ominously, and its surface hardens

颜色诡异的加深

表面变硬

into an alien topography of peaks and craters.

如同外星球的坑坑洼洼

Then, the kitchen timer dings.

然后，厨房计时器响了

Your cookie is ready.

饼干做好了！

What happened inside that oven?

烤箱里发生了什么

Don't let the apron deceive you!

别被面包师的围裙唬住了

Bakers are mad scientists.

他们可是疯狂的科学家呢

When you slide the pan into the oven,

当你把烤盘放进烤箱时

you're setting off a series of chemical reactions

你就开启了一系列化学反应：

that transform one substance, dough, into another, cookies.

一种物质-面团

被转变成另一种物质-饼干

When the dough reaches 92 degrees Fahrenheit,

面团温度达到92华氏度时

the butter inside melts,

里面的黄油融化

causing the dough to start spreading out.

面团瘫软下来

Butter is an emulsion,

黄油是一种乳化剂

or mixture of two substances

或者说是两种物质的混合物

that don't want to stay together,

这两种物质可不想呆在一起

in this case, water and fat,

在这里，指的是水和脂肪

along with some dairy solids that help hold them together.

一些乳脂块

将水和脂肪混合在一起

As the butter melts, its trapped water is released.

黄油融化时

里面水分被释放出来

And as the cookie gets hotter, the water expands into steam.

饼干继续升温

水分膨胀成气体

It pushes against the dough from the inside,

从里往外挤迫面团

trying to escape through the cookie walls

想要冲出面团的束缚

like Ridley Scott's chest-bursting alien.

就像雷德利·斯科特电影《异形》中的场景

面团里的鸡蛋

Your eggs may have been home to squirming salmonella bacteria.

可是沙门氏菌的窝巢

An estimated 142,000 Americans are infected this way each year.

据估计，每年有142,000美国人

被这种细菌感染

Though salmonella can live for weeks outside a living body

虽然在沙门氏菌可以存活数周

在体外

and even survive freezing,

甚至冰冻的环境里

136 degrees is too hot for them.

但烤箱内的136华氏度对他们来说太热了

When your dough reaches that temperature, they die off.

当面团达到136华氏度时

这种细菌就死了

You'll live to test your fate with a bite of raw dough

所以偷偷咬一口

还没进烤箱的生面团

you sneak from your next batch.

是在拿生命冒险呢

At 144 degrees, changes begin in the proteins,

温度达到144华氏度时，蛋白质开始变化

which come mostly from the eggs in your dough.

蛋白质一般来源于面团中的鸡蛋

Eggs are composed of dozens of different kinds of proteins,

鸡蛋含有很多种

不同的蛋白质

each sensitive to a different temperature.

每种的敏感温度不一样

In an egg fresh from the hen,

刚生出来的鸡蛋

these proteins look like coiled up balls of string.

里面的蛋白质像一团团的线

When they're exposed to heat energy,

加热鸡蛋时

the protein strings unfold and get tangled up with their neighbors.

蛋白质伸展开来

和周围的分子混在一起

This linked structure

相互缠绕的蛋白质

makes the runny egg nearly solid,

使流体的蛋几乎凝固

giving substance to squishy dough.

从而让湿乎乎的面团便硬

Water boils away at 212 degrees,

水分在212华氏度时完全变成蒸汽

so like mud baking in the sun,

就像阳光下炙烤的泥团

your cookie gets dried out and it stiffens.

饼干变干变硬

Cracks spread across its surface.

表面布满小裂缝

The steam that was bubbling inside evaporates,

沸腾的水滴蒸发

leaving behind airy pockets that make the cookie light and flaky.

留下一个个小坑

使得饼干又薄又脆

Helping this along is your leavening agent,

这一切都得益于发酵物

sodium bicarbonate,

碳酸氢钠

or baking soda.

或烘焙苏打

The sodium bicarbonate reacts with acids in the dough

碳酸氢钠和

面团里的酸反应

to create carbon dioxide gas, which makes airy pockets in your cookie.

产生二氧化碳气体

这些气体在饼干表面留下了一个个小坑

Now, it's nearly ready for a refreshing dunk

现在，就快能蘸着牛奶

in a cool glass of milk.

享受你的饼干了

One of science's tastiest reactions

其中最增添美味的一个反应

occurs at 310 degrees.

发生在310华氏度

This is the temperature for Maillard reactions.

叫做美拉德反应

Maillard reactions result

这个反应是由于

when proteins and sugars break down and rearrange themselves,

蛋白质和糖分解

并重新结合

forming ring-like structures,

形成环状结构

which reflect light in a way

可以反射光

that gives foods like Thanksgiving turkey

这样感恩节烤火鸡

and hamburgers

和汉堡包

their distinctive, rich brown color.

就拥有了独特诱人的褐色外表

As this reaction occurs,

该反应会产生

it produces a range of flavor and aroma compounds,

大量美味又芬芳的化合物

which also react with each other,

其相互之间还在反应

forming even more complex tastes and smells.

产生更加浓郁的香气和味道

焦糖化反应

Caramelization is the last reaction

to take place inside your cookie.

是最后发生的反应

Caramelization is what happens

焦糖化反应是指

when sugar molecules break down under high heat,

糖分子在高温下分解

forming the sweet, nutty,

产生甘甜、像坚果一样

and slightly bitter flavor compounds that define, well, caramel.

而且略发苦的化合物

也就是焦糖

And, in fact, if your recipe calls for a 350 degree oven,

实际上，如果菜谱设定的烤箱温度为350华氏度

it'll never happen,

焦糖化反应就不会发生

since caramelization starts at 356 degrees.

因为这个反应发生温度为356华氏度

If your ideal cookie is barely browned,

要想使饼干颜色略微加深

like a Northeasterner on a beach vacation,

如同来沙滩度假的东北人

you could have set your oven to 310 degrees.

最好把烤箱温度设定为310华氏度

If you like your cookies to have a nice tan,

如果希望饼干呈现漂亮的棕褐色

crank up the heat.

就调高温度

Caramelization continues up to 390 degrees.

390华氏度内焦糖化反应都会继续

And here's another trick:

这里还有个小窍门

you don't need that kitchen timer;

你其实不用买计时器

your nose is a sensitive scientific instrument.

鼻子就是灵敏的科学仪器

When you smell the nutty, toasty aromas

当你闻到坚果般温暖迷人的香味时

of the Maillard reaction and caramelization,

香味来自于美兰德反应和焦糖化反应

your cookies are ready.

你的饼干就烤好了

Grab your glass of milk,

倒一杯牛奶

put your feet up,

翘起脚

and reflect that science can be pretty sweet.

你会发现科学也能很甜蜜