在炒蘑菇上挤一些新鲜的柠檬汁，或将一点点葡萄酒醋洒到豆类汤中，您会迅速品尝到酸如何使食物的味道变亮。但是酸性成分在烹饪方面的作用要比增强口味要多得多。它们对水果和蔬菜的颜色和质地产生了重大影响。

但是，固定酸影响食谱中成分的精确方式有些棘手，因为酸似乎是自相矛盾的。他们一次又一次地矛盾。就在您认为自己了解酸的行为时，它们会转身做相反的事情。

For example, acids make cooked broccoli fade to a dull grayish green; and yet acids also prevent cooked red cabbage from turning blue. Acids help pickles stay crisp and delicious; but then again, vinaigrette seems to make lettuce go limp. So, do acids drain color or protect it? Keep food firm or turn it soft? Answer: all of the above.

Fortunately, acids aren’t fickle; they follow a simple set of rules. Learn them and you’ll be able to use acids to your advantage when cooking fruits and vegetables.

What’s an acid?

大多数情况下，当我们谈论酸时，我们的意思是您添加到食物中的酸成分。其中一些酸很明显，但其他一些酸可能会让您感到惊讶。即使是轻微的酸性成分，以及在烹饪过程中也会引起颜色或质地的变化。这是一些常见的酸性成分：

• 尖酸刻薄

•柠檬和酸橙

• tomatoes

• 葡萄酒

• molasses

• soy sauce

• yogurt

• buttermilk

酸如何影响颜色

Fruits and vegetables get their colors from different natural chemical pigments. When a fruit or vegetable changes color during cooking, the pigments have undergone a chemical reaction—and more often than not, acids are involved. Here’s what’s going on:

Acids help red fruits and vegetables stay red.红色cabbage, red grapes and plums, cherries, cranberries, strawberries, and raspberries contain pigments called anthocyanins, which are responsible for most of the red, purple, and blue colors in plants. Anthocyanins turn red in acidic environments and blue in alkaline environments. So when cooking a red fruit or vegetable, adding an acidic ingredient such as vinegar, lemon juice, or tomato juice helps prevent the food from turning purple or blue.

酸将绿色蔬菜变成泥泞。以西兰花为例。短暂蒸，变成了充满活力的绿色。煮沸15分钟，变成橄榄色。这也发生在其他绿色蔬菜中，例如菠菜，羽衣甘蓝，甜豌豆和绿豆。这些蔬菜煮的时间越长，它们的细胞壁越多。天然酸逃脱细胞并与绿色色素叶绿素反应，使其变暗。

So how can you cook a green vegetable and keep its color bright? Cook it to a minimum, using a quick-cooking method such as steaming, boiling, or stir-frying. Less cooking time means less opportunity for acids to escape the cells and react with chlorophyll. If you don’t plan to eat steamed or boiled green vegetables as soon as they’re cooked, plunge them into icy water to bring the cooking (and the escape of acids) to a halt. And if you want to season a cooked green vegetable with lemon juice or vinegar, do it right before serving or the color will fade.

也就是说，绿色不是一切。借助炖肉或炖煮的缓慢烹饪方法，您可以牺牲绿色蔬菜的颜色，但您会获得更深的风味。

橙色和黄色的蔬菜不介意酸。胡萝卜，南瓜，地瓜，西红柿和红辣椒从称为类胡萝卜素的色素中获得颜色，这些类胡萝卜素对酸是相对免疫的。

How acids affect texture

Textural changes in fruits and vegetables—as when they become tender during cooking— have to do with cell walls breaking down. Acids can prevent texture changes or encourage them, depending on the situation.

在酸性环境中，水果和蔬菜保持牢固。如果您曾经尝试将生洋葱或其他蔬菜添加到已经沸腾的番茄酱中，那么您就会知道蔬菜不会变软。那是因为即使在烹饪数小时后，蔬菜和水果中的纤维素也不会溶解在酸性状态下。因此，在加入西红柿，葡萄酒或其他酸性成分之前，将水果和蔬菜煮至所需的质地。而且，如果您要追随的质地更牢固，就像在偷猎梨时，烹饪液体的战略添加应该可以解决问题。

使用干燥的豆类，战术使用酸可以帮助您实现既不结实也不太软但恰到好处的质地。例如，当制作烤豆（使用糖蜜，酸性成分）或番茄豆汤时，将豆子浸泡并煮在水中，直到它们变软为止。然后添加您的酸性酱或汤食材，这将有助于将豆子的外部固定，因此它们不会太糊状，因为它们进一步烹饪并吸收了酱汁或汤的味道。

酸（和油）使生菜变得笨拙。When a dressed salad wilts, both the oil and the acid in the dressing are to blame. The oil in a vinaigrette briefly protects the surface of lettuce leaves from the acid, which will make the leaves turn dark. But before long, the oil breaks through the waxy coating on the leaves’ surface. When this happens, the leaves soak up the dressing, wilt, and darken. Cuts and tears on the lettuce also let vinaigrette seep into the leaves.

当然，没有湿醋汁的绿色沙拉不是沙拉。因此，如果您希望自己的美味并具有令人愉悦的质地，请在食用前立即穿好衣服。

Acids help jams and jellies set

Setting jams and jellies successfully depends on a balance between acid, pectin, and sugar. Acid encourages the natural pectin in fruit to gel. Fruits like sweet apples, peaches, pears, apricots, and sweet cherries don’t release enough natural pectin during simmering, so jams using these low-acid fruits usually include lemon juice or highly acidic fruit (sour cherries, tart apples, rhubarb) to increase the gelling power.