蛋挞作为一种经典的甜点，深受人们喜爱。然而，你可能会好奇为什么在制作蛋挞时不需要加入蛋白。事实上，这个问题涉及到蛋挞独特的口感和外观。

首先，让我们来了解一下蛋挞的制作过程。蛋挞的外皮通常是用面粉、牛油和鸡蛋黄制成的。而内馅则是由牛奶、砂糖、香草精和鸡蛋黄混合而成。可以看出，鸡蛋黄在蛋挞中起着重要的作用。

蛋挞的外皮需要蛋黄来增加黄色的颜色和丰富的口感。蛋黄含有丰富的脂肪和卵磷脂，这些成分能够提供丰富的口感和浓厚的香味。同时，蛋黄还有助于调整蛋挞的黄色程度，使其更加吸引人。

而对于蛋白来说，它的特性与蛋黄有很大的区别。蛋白质主要由水分和蛋白质组成，它的特点是粘稠和弹性。如果将蛋白加入蛋挞中，会使得蛋挞的口感变得过于胶状，失去了原本酥脆的外皮。

另外，蛋白还有一种特性是容易产生气泡。在制作蛋挞时，我们希望内馅表面光滑细腻，没有气泡。而蛋白的加入很可能会导致气泡的产生，影响蛋挞的整体质量。

总的来说，蛋挞之所以不需要蛋白，是因为蛋黄能够提供丰富的口感、香味和颜色，而蛋白则会使蛋挞变得粘稠和胶状。此外，蛋白还容易产生气泡，影响蛋挞的质量。因此，在制作蛋挞时，只加入蛋黄能够更好地保持蛋挞的原始风味和口感。

In the making of egg tarts, it is a curious fact that egg whites are not added. The answer to this lies in the unique texture and appearance of egg tarts.

Firstly, let us understand the process of making egg tarts. The pastry of an egg tart is typically made with flour, butter, and egg yolks. The filling, on the other hand, consists of milk, sugar, vanilla extract, and egg yolks. It is evident that egg yolks play an important role in egg tarts.

The egg yolks are necessary for the pastry as they provide a rich golden color and a delightful texture. Egg yolks are rich in fats and lecithin, which contribute to a smooth and aromatic sensation. Moreover, egg yolks help to adjust the yellow hue of the egg tarts, making them more appealing.

On the contrary, egg whites possess distinct characteristics from egg yolks. Egg whites consist mainly of water and proteins, giving them a viscous and elastic nature. Adding egg whites to egg tarts would result in a gummy texture, deviating from the original crispy crust.

Furthermore, egg whites have a tendency to generate bubbles. In the process of making egg tarts, we aim for a smooth and delicate surface for the filling, without any air bubbles. The addition of egg whites could potentially introduce unwanted bubbles and affect the overall quality of the egg tart.

In conclusion, egg tarts do not require egg whites because egg yolks provide richness in flavor, aroma, and color, while egg whites would contribute a gummy texture. Additionally, egg whites tend to create bubbles, compromising the quality of the egg tart. Hence, in the making of egg tarts, by solely utilizing egg yolks, we can preserve the authentic taste and texture of this delightful dessert.