How does "China's sexiest steamed buns" lock in the broth? There are many details behind traditional delicacies

Many traditional delicacies have unique flavors and tastes. Have you ever wondered: where does the fragrance and chewy texture of Guangxi's raw rice noodles come from, or the delicate and smooth texture of Guangdong's double-skin milk come from? How does a thin layer of dough lock in the rich soup and crab aroma in Jingjiang's crab roe soup dumplings?

For a long time, the secrets of these traditional local cuisines have often been attributed to the talent of the chef or the secret master-apprentice inheritance, and the answer is simply "the master taught me."

In fact, there are many scientific mysteries behind these unique flavors and tastes. Now, "Molecular Gastronomy for Foodies" can help you uncover the veil of these delicacies. It explores the delicacies on the tip of your tongue from a scientific perspective and explains the origins of these delicacies from the perspective of molecular gastronomy.

What is special about Guangxi raw rice noodles?

Compared with other famous food regions, Guangxi's cooking is relatively simple. However, there is a unique skill here: raw rice noodles.

Raw rice noodles production. Image source: Xinhua News Agency

The characteristic of raw rice noodles is that they are "freshly squeezed and eaten". Usually there is a large basin of very sticky rice paste in the store. The store owner puts the rice paste into a mold and squeezes it out from the small hole at the bottom of the mold to make uniform vermicelli. These vermicelli are squeezed directly into boiling water. After tens of seconds to a few minutes, the vermicelli floats up. The cooked rice noodles are taken out and poured into the freshly made leek and pork soup. The fresh fragrance that cannot be experienced in high-end restaurants immediately spreads. It is said that more "particular" stores will take out the cooked noodles and cool them down with cold water before adding them to the hot soup for customers to eat.

In fact, different parts of China have their own unique rice noodles and pasta. The key to making them delicious lies in two aspects: the texture of the rice noodles and the taste of the soup.

Speaking of taste, Guangxi raw flour does not have any drying steps in the entire production process. The starch is always in a state of absorbing water and retaining moisture. When cooked, it is more uniform from the outside to the inside and can maintain better "viscoelasticity".

As for cooling down with cold water, there is a reason behind it. As a kind of "starch glue", the structural state of starch molecules and the entanglement and interaction between different starch molecules will continue to change during the heating and cooking process of rice noodles. When they are cooked to the ideal state, cooling them down to "fix them in place" will also help maintain a better taste.

The double skin milk you made

Why do you always fail?

Shuangpi Nai is a famous snack in Guangdong. The process of making this dessert is not complicated, but many people cannot replicate it at home.

Cantonese style double skin milk. Image source: Tuchong Creative

What is the problem? Or, how to make a perfect double skin milk?

First of all, it is best to use buffalo milk to make double skin milk.

The "skin" of double-skin milk is formed by the cross-linking of proteins wrapped around fat particles after the fat particles float to the surface. Compared with the milk we usually drink, buffalo milk has higher protein and fat content, and the fat particles are larger, so it is easier to form a skin.

The milk we usually drink is usually homogenized under high pressure to prevent fat particles from floating up and stratifying, so it is almost impossible to form milk skin. If you want to make it with ordinary milk, you can try using whole milk and adding some cream to it.

Secondly, overheating will completely denature the protein, and the effect of making double skin milk is not the best. Instead, the best effect is when the protein is partially denatured. In other words, when the milk is heated to a "slightly boiling" state with many small bubbles, you can stop heating, and then pour the heated buffalo milk into a bowl and let it sit. After a while, a layer of "milk skin" will appear.

There is another key point: the core of the coagulation of double skin milk is not the milk, but the added egg white . The added egg white needs to be fully opened. Because there are many mucins in the egg white, if it is not fully "homogenized", it will easily gather together when added to the milk and will not disperse, and it will not form a "milk gel" with a uniform texture.

After beating the egg whites, the maker needs to judge the temperature of the milk. When the temperature drops to the right level, pour the homogenized egg whites in and continue stirring. For seasoning, you can also add some sugar. In this step, it is very important to control the temperature. Although the high temperature of hot milk is conducive to the dissolution of white sugar, eggs will solidify above 57°C. If the milk temperature is higher than this, the egg whites will not be mixed evenly before they are poured in, and egg flowers will appear.

Jingjiang Crab Roe Soup Dumplings:

How does the "sexiest steamed bun in China" lock in the broth?

Jingjiang's crab roe soup dumplings are large, with thin skin and full of soup. Because of the thin skin and rich soup, when you shake the steamer, you can see the dumplings dancing, and they are called "China's sexiest dumplings." Rather than dumplings, they are more like "a bowl of seafood soup" but in an edible dough bag.

Jingjiang crab roe soup dumplings. Image source: Tuchong Creative

Jingjiang soup dumplings actually embody various food engineering principles.

Let's talk about the bun wrapper first. The wrapper of Jingjiang soup buns is very thin. The dough required for a bun with a diameter of 11 cm is only as big as the wrapper of ordinary dumplings. This requires that it be rolled very thin in order to hold nearly three taels of soup. This requires not only good ductility of the dough, but also good mechanical strength. Only high-gluten flour can be used to make this kind of buns. When kneading the dough, alkali and salt must be added, and then the dough must be fully kneaded . There is gluten protein in the flour, which is a protein with a high content of hydrophobic amino acids and is insoluble in water. When kneading the dough, it absorbs enough water and stretches out during the kneading process. Amino acids from different molecules come together and "hook shoulders and back" to form a tight connection. All gluten molecules are entangled with each other, forming a huge network, which encircles the starch molecules and forms dough.

The mechanical strength of the dough mainly depends on the degree of entanglement between these gluten proteins. The high gluten content in high-gluten flour, and the addition of alkali and salt promote their stretching and cross-linking, thus obtaining a high-strength dough. If the rolled bun skin is wrapped into an empty bun, it can be blown up like a balloon, which shows its good ductility and mechanical strength.

The soup in the buns cannot be poured directly into the buns. Our clever ancestors discovered that the soup made from pig skin would solidify at room temperature and melt at high temperature, so they boiled and dissolved the pig skin, solidified it into jelly, and wrapped it in the bun skin. In other words, the production of soup dumplings is to wrap the pig skin jelly as the filling, and wait until the buns are steamed and the jelly melts into soup, and then it becomes a soup dumpling.

The main component of pig skin is collagen, which is also a highly hydrophobic protein. Only when heated for a long time at high temperature can it "reluctantly" stretch out and dissolve in water. But when the temperature drops, they cannot turn back, and different molecules connect with each other to form a gel, which becomes skin jelly.

Pure jelly is colorless and tasteless, and can only be used as a carrier for soup. The flavor of the soup is determined by the ingredients added. The flavor of the soup dumpling is the most important factor in making the soup. Crab roe soup dumpling naturally needs to be added with crab roe. In seasons when there is no crab roe, crab meat should also be added. In the early days, there were even soup dumplings with pork added. In addition to crab roe, there are also "river fresh soup dumplings" made with other river fresh food, and even vegetable soup dumplings.

The number of folds on a soup dumpling should be between 28 and 35. These folds are not only for beauty, but also for shock absorption.

The buns are large, thin-skinned, and filled with liquid, so they are easily broken when subjected to external shocks. These folds, like springs, can absorb and dissipate external shocks, thus ensuring the integrity of the buns. Of course, the more folds, the better, because the tops of the folds need to converge to close, and too many folds will make the closed area thicker and less easy to steam.

author

Yun Wuxin, PhD in Food Engineering, Scientific Advisor for A Bite of China 2, Chief Scientific Advisor for Origins of a Flavor (1-5)

Planning and production

Source: Book "Molecular Gastronomy for Foodies", Science and Technology Press of China

Author: Yun Wuxin, PhD in Food Engineering

Planning丨Yang Yang

Editor: Yang Yang

Proofread by Xu Lailinlin

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