Why is beef so sticky? 5 secrets hidden in the taste of food

Food not only provides us with nutrition, but also allows us to experience the joy of eating. This joy is not only brought by the delicious taste, but also by the taste, such as chewy, hard and chewable, fresh and sticky...

Why does food give us a rich taste? What secret is hidden behind it?

1. The secret of Flammulina velutipes’ durability

Mushrooms are very durable ingredients. If we rank them, the first place must be Flammulina velutipes. Everyone who has eaten Flammulina velutipes must have experienced the feeling of "stuck in the teeth" and "excessive mushrooms in the shit". The reason for this is that Flammulina velutipes is rich in chitin.

Chitin, also known as chitosan, comes from the Greek word "chiton" which means armor. It is one of the most important components of the exoskeleton and intestinal nutrient matrix of crustaceans. It is generally found in the shells of crabs, shrimps, and insects. However, chitosan was first discovered in mushrooms in 1811. It is an important component of the cell wall of edible fungi and plays a protective role. It is called "fungal cellulose." [1]

Chitin is heat-resistant and can withstand temperatures as high as 380°C.[2] It is almost insoluble in water, so normal cooking temperatures will not affect it, and long cooking times will not cause it to become mushy. This is also the reason why enoki mushrooms are not soft and difficult to chew after being cooked for a long time, and may even be excreted "as is".

Although chitin cannot be cooked, it does not mean that it cannot be digested. After being ingested by the human body, chitin can be completely degraded into glucose and then absorbed and utilized by the body. After all, it is also a kind of dietary fiber, which can promote gastrointestinal mechanical movement, promote defecation, is beneficial to intestinal health, and also helps control blood sugar.

In order to avoid wasting chitin, in addition to chewing the enoki mushrooms carefully when eating them, you can also chop them into small pieces when cooking to increase the digestible area and help the body absorb and utilize chitin. This way, it won't get stuck in your teeth and won't "see" it again in the next day's stool.

2. The secret of the chewy pork skin jelly

Have you ever eaten pig skin jelly? In Northeast my country, almost every household has to prepare a bowl of pig skin jelly every Spring Festival. It looks crystal clear and tastes chewy and tender. It tastes amazing when eaten with soy sauce, vinegar and mashed garlic!

The key secret of the chewy texture of pig skin jelly is that it is rich in collagen, which means "making glue" in Greek. Animal skin, bones, and tendons are rich in collagen, accounting for about 1/3 of the protein in the animal body. The special thing about it is that solid collagen is insoluble in cold water, but after heating in water, part of it will melt into a sticky colloid. The heated and denatured collagen molecules can be re-cross-linked into a three-dimensional network structure, which has a good ability to combine with water. After solidification, it will become crystal clear and elastic. [3, 4]

The total protein content of pig skin is about 33%, and collagen is its main protein, accounting for 87% of the total protein. [4] Therefore, pig skin is an ideal ingredient for making pig skin jelly.

Although pig skin jelly is delicious, don't expect it to beautify your skin! After all, collagen is an incomplete protein, and the human body has a low absorption rate. In addition, the collagen you eat will be broken down into amino acids for the body to use, and will not directly act on the facial skin to help us beautify our skin. In addition, the calories of pig skin jelly are not low. Eating it for beauty will make you fatter and your face bigger.

3. The secret of the viscosity of Tremella soup

Tremella is rich in various nutrients and is known as the "king of fungi". Tremella soup, Tremella lotus seed soup and other Tremella delicacies have always been very popular, especially its sticky taste after boiling, which has captured the hearts of many foodies.

Many people may say: "The sticky Tremella is especially good for collagen!" In fact, Tremella does not contain collagen. The reason why it is sticky is because it contains rich Tremella polysaccharides. A study compared the polysaccharide content in Tremella produced in 8 different regions. Among them, the highest polysaccharide content was in Gutian, Fujian, at 31.25%, followed by Shennongjia Forest District in Hubei at 30.67%, Tongjiang in Sichuan at 30.31%, Yulong in Yunnan at 28.98%, Ji'an in Jiangxi at 28.66%, and finally Dayangshu Town in Heilongjiang, Qingyuan in Zhejiang, and Kang County in Gansu. The lowest content was in Kang County in Gansu, at 24.73%. [5]

Tremella polysaccharide is a type of water-soluble dietary fiber with good water absorption and water retention. When dissolved in water, it makes the aqueous solution viscous, so the cooked Tremella soup will be sticky. Because Tremella polysaccharide has extremely strong hydrophilicity, it can absorb lipids and cholesterol, which is beneficial to the excretion of lipids and cholesterol in the intestines and plays a role in controlling blood lipids. Tremella polysaccharide also helps control blood sugar by regulating the activity of sugar metabolic enzymes, promoting insulin secretion and improving the utilization of glucose by peripheral tissues. In addition, some studies have also mentioned that Tremella polysaccharide is also helpful in anti-inflammatory, regulating immunity, and improving memory. [6]

4. The secret of beef being chewy

Among meat foods, beef is one of the most difficult to chew. It is difficult to chew and will get stuck in your teeth. Every time you finish eating beef, there will be some stubborn beef shreds left in your teeth.

The reason why beef is hard to chew is that the muscle fibers of most beef are relatively coarse. The clumping of muscle fibers gives the muscle a dense and tough texture, which becomes tighter and drier after being cooked. Animals that exercise a lot have thicker and stronger muscles, and the meat is tougher. The older the animal, the less collagen it has in its body, and what remains are more complex protein strands that are difficult to dissolve in water. [3] Meat with less fat, less water, and higher protein content will also be tougher after cooking and have a woody texture. However, calf beef has more collagen, so it has a soft texture and is tender.

Beef has a higher proportion of lean meat and less fat, and lacks "fat", so the taste will be a little drier than pork which has a relatively high fat content. If it is beef that is often used in the fields, the taste will be drier; if it is old beef, it will be harder to chew.

How can we make the beef taste softer?

- Choose the right parts: Cows are standing animals that eat grass. Their shoulders, calves, and hind legs are the parts that use the most strength, so the meat in these parts is tougher and less likely to break down. It is best to cook them for more than an hour or directly use a pressure cooker. Ribs, brisket, and tenderloin are the most tender parts of the cow. [3]

-Marinate before cooking: Before cooking beef, cut the beef into shreds, then coat it with starch, cooking wine, salt, etc. and marinate it for 15 to 30 minutes. The beef cooked in this way will not only be soft and easy to chew, but also reduce the water loss of the beef and better protect the nutrients.

5. The secret of sticky rice

The rice dumplings of the Dragon Boat Festival, the Yuanxiao and glutinous rice balls of the fifteenth day of the first lunar month, they all require the presence of glutinous rice. The most obvious taste when you put them in your mouth is that they are sticky and sticky to your teeth.

If you want to know why glutinous rice is so sticky after cooking, you have to start with starch. Starch is composed of glucose molecules, and these glucose molecules are aggregated in two ways: linear and branched. The starch structure of the rice we usually eat is mainly linear starch, and glutinous rice is mainly branched starch.

The structure of amylose is linear, it is easily soluble in hot water, and it will not form a colloidal solution, so it is not very viscous; while amylopectin is a tree-branch structure with more branches and a tighter crystal structure, which makes it difficult for water molecules to enter the interior, making the starch granules difficult to dissolve in cold water, so it is more viscous.

Therefore, foods made with glutinous rice have a stickier texture. In addition, foods made with glutinous rice generally have a higher blood sugar response after a meal,[7] so people who need to control their blood sugar should eat less of them.

What kind of food texture do you like?

References:

[1] Dai Peng, Zheng Jinlu, Liu Bingrong, Wang Ganying, Liu Feng. Chemical modification and application of chitin and chitosan[J]. Polymer Bulletin, 2020(07): 1-17. DOI: 10.14028/j.cnki.1003-3726.2020.07.001.

[2]https://www.pbs.org/wgbh/nova/article/mushrooms-overcook-heat-chitin/

[3] Harold Mackey, Food and Cooking: Milk, Eggs, Meat, Fish. Translated by Lin Huizhen. Beijing Fine Arts Photography Publishing House. August 2013.

[4] Chang Yi. Establishment of sensory evaluation system of pig skin jelly and research on its processing technology[D]. Bohai University, 2021. DOI: 10.27190/d.cnki.gjzsc.2021.000432.

[5] Chen Xiaozhen, Zeng Zaochang. Study on the polysaccharide content and in vitro transdermal absorption performance of Tremella fuciformis from different origins[J]. Journal of Guangzhou University of Traditional Chinese Medicine, 2018, 35(06): 1084-1088. DOI: 10.13359/j.cnki.gzxbtcm.2018.06.027.

[6] Xu Huanyi, Li Quancen, Zheng Mingfeng, et al. Research progress on the structure, functionality and application of Tremella fuciformis polysaccharide [J/OL]. Food Industry Science and Technology: 1-15 [2023-09-11]. https://doi.org/10.13386/j.issn1002-0306.2023040052.

[7] Pan Haikun, Wang Shuying, Fan Zhihong. Evaluation of blood glucose and satiety after meals of glutinous processed foods[J]. Food Science, 2016, 37(17): 225-229

The article is produced by Science Popularization China-Creation Cultivation Program. Please indicate the source when reprinting.

Author: Xue Qingxin, member of Chinese Nutrition Society, registered dietitian, health manager, public nutritionist

Reviewer: Ruan Guangfeng, Deputy Director of Kexin Food and Health Information Exchange Center

Source: Starry Sky Project