<h1 class= "pgc-h-arrow-right" >01, what is frying? </h1>
Any food cooked in hot oil is fried. The method of heat transfer is the same, whether there is a little fat in the pan (frying), fat on one side of the food (shallow frying), or fat completely wrapped around the food (fried). When food is added to hot oil (usually 176 ° C), its surface is dehydrated. At the same time, through a series of Maillard reactions (named after chemist Louis Camille Maillard), its sugars and proteins break down to produce a complex flavor and golden yellow.
Browning is quick and thorough because hot liquid fats transfer heat to the smallest crevices on the surface of food. At the initial moment of frying, the surface dehydrates, forms a hard shell, inhibits further oil absorption, while continuing to heat the inside of the food, leading to starch gluing (such as fries), protein denaturation (such as fried chicken), and fiber softening (fried zucchini).
Keeping the right oil temperature is key to frying. If the temperature drops too low, the crust will slowly form, allowing the food to absorb more fat and become greasy. If the oil is too hot, the food burns on the surface before it passes.
Image credit: pixabay
<h1 class="pgc-h-arrow-right" >02, what cooking oil is best used when frying? </h1>
It depends on whether you're most concerned about taste or health, or whether you're using long-lasting frying oil. Different fats produce better results in every situation. The hydrogen saturation of fat is the most important variable. High saturated fats, such as lard and shortening, are solid at room temperature, while polyunsaturated fats, such as vegetable oils and rapeseed oils, remain liquid at room temperature.
Foods fried in high saturated fats are more palatable on the surface and have less oil flavor than foods fried in unsaturated fats because saturated fats re-solidify after cooling. In addition, many saturated fats, such as duck and beef fat, are more delicious than refined liquid oils. So from the taste and texture point of view, solid fat is a good choice for frying.
However, saturated fats are considered less healthy than liquid polyunsaturated fats because they may be associated with a high risk of cardiovascular disease. In addition, during the frying process, saturation causes these fats to degrade more quickly. They begin to decompose at a typical frying temperature of 190 ° C, releasing free fatty acids, burning and appearing visible smoke. Once the fat reaches this smoke point, it produces odors and toxic odors.
For longer-lasting, healthier fats, choose refined polyunsaturated oils with high smoke points. Almost all vegetable oils are better choices because they have higher smoking point temperatures, from 210 °C (corn oil and olive oil) to 223 °C (rapeseed oil) to 229 °C (grape seed oil) to 232 °C (peanut, soybean and safflower oil).
<h1 class = "pgc-h-arrow-right" >03, the top ten secrets of frying</h1>
1. Cut the food into pieces of similar size so they can be fried at the same rate.
2. To help the crumb coating dry and adhere, let the raw crumbs leave on the rack for 30 minutes before frying.
3. Always fry in a deep pan filled with only one-third or half of the oil. The tall and narrow pan helps to extend the frying life of the oil, as the surface of the oil is rarely exposed to oxygen.
4. Using a frying thermometer, adjust the temperature to maintain a stable temperature while frying.
5. Fry in small batches to prevent oil temperature from being too low and causing greasy food.
6. Drain the fried food slightly on a shelf or on absorbent paper.
7. Season immediately after frying so that the seasoning sticks to the hot food.
8. If you do not eat immediately, transfer each batch of fried food to a 100 ° C oven to keep it crisp.
9. Let the oil return to the frying temperature between batches.
10. Never leave the oil on the stove unattended – it can overheat and become a fire hazard.
<h1 class="pgc-h-arrow-right" >04, How is the crispy crust of fried food formed?</h1>
When food is immersed in hot oil, the water in the food begins to boil and oozes out of the surface. In order to form a crisp and dry shell, there must be a barrier between the hot oil and the flowing water. This barrier is typical of the amyloid thing. When starch is stir-fried in hot oil, it dries out and turns into a pleasantly crispy shell that protects the moisture underneath. The food inside is steaming hot, while the outer layer is brown.
After frying, the food continues to steam, but as soon as you can see the steam rising from the surface of the fried chicken or tempura, the moisture will be lost and the coating will remain crispy. Once the food has cooled and the steam stops, the remaining moisture inside is absorbed into the coating, making it moist; that's why fried foods are best eaten immediately after frying.
Starch is naturally found in some foods, such as potatoes and fried foods, but for fried foods, especially meat and fish, starch coatings such as batters or breadcrumbs need to be added. Both produce crispy crust during frying, and both have pros and cons. They are better suited for frying delicate ingredients, such as fish chops, as they break down easily during cooking.
The downside of pastor layers is that they don't evaporate as easily as breadcrumbs, so fragile foods tend to soak faster. For crisp batters, using low-protein wheat flour, such as low-protein flour, doesn't produce as much gluten as high-protein flour does, so it doesn't become chewy. For more crisp crusts, use corn flour (ground corn flour) or gluten-free rice flour.
The breadcrumb coating remains crunchy longer than the dough layer, but the process of making the breadcrumb coating can be more complicated: typically, the food needs to be sprinkled with flour to dry its surface, and then soaked in eggs to help the crumbs adhere and form a crust.
To make the crispest crustings, you can use breadcrumbs, which are long strips rather than round, and they have a larger surface area exposed to hot oil, so they are more brittle and not compressed like ordinary breadcrumbs, which allows the steam to evaporate faster and helps prevent the crust from becoming moist.
<h1 class= "pgc-h-arrow-right" >06, pastry frying technical essentials</h1>
Pastry frying is the process of cooking a molded raw blank into an oil that has been heated to a certain temperature. Frying is a mature method that is widely used in pastry production and has strong adaptability, which has the advantages of saving energy, strong flavor of the finished product, bright color, beautiful shape, and a variety of patterns, and almost all kinds of dough products can be matured by frying methods.
First, the principle of frying
In the frying process, convective heat exchange plays a role in accelerating the maturity of products, the heated grease and product blanks undergo a violent convection cycle, the products floating on the oil surface are subjected to the strong convection effect of boiling grease, and part of the heat is absorbed by the product and the internal temperature gradually rises, and the moisture is continuously heated and evaporated.
Compared with water, the oil temperature can rise to a very high, the product is surrounded by grease on all sides of the heat at the same time, at such a high temperature, the product quickly matures and the color is uniform. In addition to playing a heat transfer role, the grease itself is absorbed into the inside of the product, increasing the nutritional value of the product. Under the same heating conditions, the oil can be increased by up to 1 times before the temperature of water, so the use of fried food can save energy.
Second, the essentials of frying technology
The key to frying lies in the mastery of the oil temperature and the time of frying. The level of oil temperature and the length of frying time should be grasped according to the variety of products, raw materials, block size and thickness, heating area size and other factors. The oil temperature is high, it is easy to make the product uncooked or fried; the oil temperature is too low, so that the color of the product is light, fragile, and the taste is poor, which cannot meet the quality requirements, but also consumes fuel and takes time.
1. Oil temperature control
Oil temperature control is preferably based on a thermometer, but can also be mastered with long-term experience of proficiency. When the temperature is too high or too low, measures should be taken to make the oil temperature reach the temperature required for fried products. When the general temperature is too high, it can be taken to control the fire source, add cold oil and increase the number of raw blanks to reduce the oil temperature; when the temperature is too low, the firepower can be increased, the number of raw blanks can be reduced, and the temperature rises.
2. Fry at the appropriate temperature
The appropriate temperature for frying refers to the oil temperature at which the inside of the food reaches an edible state and the surface just reaches a certain color requirement. The oil temperature of pastry frying is divided into two types: warm oil and hot oil. (1) Warm oil: refers to the oil temperature of 80 ~ 150 ° C, that is, the industry's so-called 30% to 50% oil temperature. Warm oil is suitable for frying layer puff pastry products, and mostly fried with lard, which can better ensure the original color and form of the products, such as lily crisp and magnolia crisp fried in lard, which are white as jade, and the form is realistic. (2) Hot oil: refers to the oil temperature above 180 ° C, that is, 70% of the oil temperature. Hot oil products are mostly fried with vegetable oil, the color of the products is golden, the taste is crisp and crispy, or the outside is crisp and tender, and the filling is sweet and delicious.
Whether it is fried in warm oil or hot oil, the specific oil temperature should be determined according to the needs of the variety. High and low oil temperatures will affect the quality of the finished product.
3. The frying oil must be kept clean
During the frying process, the product will scatter some debris, precipitate part of the sugar, protein, etc., these substances in the high temperature of carbonization, not only will make the oil color darker, affect the color of the product, but also easy to adsorb on the surface of the product, affecting the appearance. Especially for varieties with delicate flower types, such as anchovy puff pastry oil cake, chrysanthemum crisp, etc., if the surface adsorbs impurities, it will affect the formation of its pattern and break the pattern.
Under the action of high temperature, air and falling impurities, the taste of oil that has been used many times has deteriorated, the smoke point has decreased, the color has changed from golden yellow to opaque black brown, easy to bubble, the nutritional value has become lower, and toxic substances have been produced, and the use of such oil to fry food is not only poor in color and taste, but also affects health. Therefore, the frying oil should often remove impurities, and after repeated use, it is necessary to replace the new oil.
Third, the common problems of fried fritters
1. The fried fritters have a very hard texture and are soft and fast (especially hard when it is cooled).
Workaround:
(1) Reduce the oil temperature when frying to extend the frying time.
(2) Use special frying oil, the finished product is brittle.
(3) Add 5% oil (1 kg of oil for 1 kg of noodles) or eggs to the noodles.
2. There is a lot of foam when frying fritters
Generally, there will be more fried fritter foam in peanut oil and rapeseed oil, and it can be fried with salad oil or palm oil.
3. How to control the oil temperature of fried fritters
The oil temperature should be 210 ~ 230 ° C, fry for 1 ~ 2 minutes until the surface is golden brown, pay attention to turning when frying, to avoid uneven heat.
4. Why do the noodles are easy to separate when the fritters are fried
Raw dough slices are left too long to dry, or too much flour or oil can cause the dough to fall apart when fried. It should be noted that when the two dough pieces are stacked and formed, except for the middle part that can be bonded, the other parts should not be bonded, otherwise the fluffiness of the fried fritters is not good, and the shape is strange. You can dip a little water in the middle.
5. How to judge the right oil temperature without a thermometer
First, heat the oil, use dry bamboo chopsticks (not dipped in oil and water) in the hot oil, the bamboo chopsticks immediately boil around, that is, adjust the fire to the minimum fire, start frying; if you use new oil, the oil begins to smoke, indicating that the oil temperature is too high.
6. What to pay attention to when frying fritters
Place the raw dough in a frying pan and let it float, turning the dough until it is puffed.
Source: Food R & D and production Finishing, please indicate the source when reprinting.
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