Basic introduction to starch
Starch can be seen as a homopolymer of glucose. In addition to food, starch is used industrially in the manufacture of dextrin, maltose, glucose, and alcohol lamps, and is also used in the preparation of printing paste, sizing of textiles, gluing of paper, and pressing of pharmaceutical tablets. It can be extracted from starch-containing substances such as corn, sweet potato, wild acorn and kudzu.
Starch is a nutrient stored in the plant body, stored in the seeds and tubers, all types of plants in the starch content is high, rice contains starch 62% to 86%, wheat contains starch 57% to 75%, corn contains starch 65% to 72%, and potatoes contain more than 90% starch. Starch is an important part of food, chewing rice, etc. feel some sweetness, this is because the saliva in the amylase enzyme starch hydrolyzed into a disaccharide - maltose. After food enters the stomach and intestines, it can also be hydrolyzed by salivary amylase secreted by the pancreas, and the glucose formed is absorbed by the wall of the small intestine and becomes a nutrient for human tissues. Partial hydrolysis of branched-chain starch produces a mixture called dextrin. Dextrins are mainly used as food additives, glues, pastes, and in the manufacture (finishing) of paper and textiles.
Types of starch:
The starch used for thickening, also called agglomerates:
It is a polysaccharide polymer formed by the condensation of several glucose molecules. Starch for cooking, mainly mung bean starch, tapioca starch, sweet potato starch, sweet potato starch, potato starch, wheat starch, lozenge starch, lotus root starch, corn starch and so on. Starch is insoluble in water, in and water heated to about 60 ℃ (different types of starch, paste temperature is not the same), then paste into a colloidal solution. Thickening is the use of this property of starch.
Mung bean starch
Mung bean starch is the best starch and is generally rarely used. It is made from mung beans soaked up with water and ground, then precipitated. It is characterized by sufficient viscosity, small water absorption, and white and glossy color.
Potato starch
Potato starch is a commonly used starch in the family, which is made from grated potato, kneaded and precipitated. It is characterized by sufficient viscosity, fine texture, white color and better luster than mung bean starch, but poor water absorption.
Wheat starch
Wheat starch is wheat bran after washing gluten, precipitation or made from flour. Characteristics are: white color, but poor luster, quality is not as good as potato flour, thickening easily precipitated.
Sweet potato starch is characterized by strong water-absorbing capacity, but the viscosity is poor, no luster, dark red with black color, by the fresh potato grinding, kneading and washing, precipitation and become.
In addition, there are corn starch, rhododendron starch, lotus root starch, water chestnut starch and so on.
The efficacy and role of starch
To replenish the middle and blood, beneficial to the qi and fluids, wide stomach and intestines, constipation
Nutritional value of starch
Because of the treatment of slurry, powder, paste, juice and gravy made with thickening powder, it can also play a role of the protective layer to prevent both the Nutrient loss or destruction, but also to avoid animal protein exposure to high-temperature scorching and the production of substances detrimental to health.
Starch consumption
Thickening is the process of pouring well-mixed starch sauce on the dishes or in the soup when the dishes are nearly mature, so that the soup is thick and adheres or partially adheres to the dishes. Yuan Mu, in his book "With the Garden Food List. Fiber with knowledge" said: "commonly known as soybean meal for fiber, that is, pulling the boat with fiber. The name must be taken into account. Because the treatment of meat to be a group and can not be combined, to be made into a soup and can not be greasy, so the powder to pull together. Frying time, consider the meat stick to the pot, will be scorched old, so use the powder to hold it. This is also the meaning of fiber." Gravy is from the fiber to sound, so now commonly known as "gravy".
Whether the gravy is appropriate, the quality of the dish has a great impact, therefore, thickening is one of the basic skills of cooking. Thickening is mostly used for simmering, slippery, frying and other cooking techniques. These cooking methods **** with the same characteristics are: the fire quickly into. With this method of cooking dishes, basically no soup. However, due to the cooking of certain sauces and seasonings and raw materials itself out of the water, so that the dishes look soup increased, through the thickening, so that the consistency of the juice increased, and attached to the surface of the raw materials, so as to achieve the dishes glossy, smooth, tender and delicious flavor.
Thickening is generally used in two ways. One is the starch juice and seasonings, commonly known as "juice", mostly used for fire power, fast speed of simmering, bursting and other methods of cooking dishes. The other is simply starch juice, also known as "wet starch", mostly used for general fried dishes. Pouring juice is also a kind of thickening, also known as thin gravy, glazed gravy, mostly used for simmering, burning, steak and soup dishes. According to the cooking method and the characteristics of the dishes, there are generally the following kinds of gravy usage:
Packet gravy is generally used for stir-fry method of cooking dishes. Powder sauce is the thickest, the purpose is to make the gravy all wrapped up to the raw materials, such as shredded pork with fish, fried cashews, etc., are used to wrap the gravy, eat the dishes, the bottom of the plate basically does not leave the marinade.
Paste cross generally used for simmered, slippery, stewed, braised method of cooking dishes. Powder juice is thinner than the package of gravy, the use of the soup of the dishes into a paste, to achieve the soup and vegetables fusion, taste smooth and soft, such as: sweet and sour pork, sweet and sour carp, and so on.
Streaming gravy is thinner, generally used for large or whole dishes, its role is to increase the flavor and luster of the dishes. Generally in the dishes on the plate, and then the pot of marinade heating thickening, and then poured on the dishes, part of the dip in the dishes, part of the glazed state, after eating the plate can be part of the remaining juice.
Milk soup gravy is the thinnest gravy, also known as thin gravy. Generally used for braised dishes, such as: spicy tofu, shrimp potpourri. The purpose is to make the dish soup a little thicker to achieve the color and taste fresh requirements.
Because of the different flavor requirements of the dishes, thickening the main role of the following:
1, increase the consistency of the soup. Dishes in the heating process, the juice in the raw materials will flow outward, with the addition of soup and liquid condiments will be fused to form a marinade. General stir-fried vegetables in the marinade is thin, not easy to adhere to the surface of the raw materials, into the dish will produce a "not flavorful" feeling. After thickening, the thickening effect of the paste to increase the consistency of the marinade, so that the marinade can be more attached to the dishes on top, improving the people's feelings about the flavor of the dishes.
2, gravy hooked into the dishes, gravy will be tightly wrapped around the raw materials, thus stopping the water inside the raw materials overflow, which maintains the flavor characteristics of the dishes fresh, smooth and tender, but also to make the dishes full of form and not easy to break up.
3, thickening, due to the paste of starch, with a transparent colloidal luster, can be dishes and seasoning color more distinctly reflected, so that the color of the dishes more bright and beautiful.
4, thickening of dishes can make the soup thicker, can slow down the internal heat emission of raw materials, so that the dishes have heat preservation, prolonging the cooling time of the dishes, and is conducive to diners eating hot dishes.