In recent years, the use of puffing technology at home and abroad to produce a series of snack foods, its characteristics are crisp and refreshing, easy to digest and absorb, so it is favored by consumers. The food is expanded into high temperature puffing and screw extrusion. The author has made in-depth research on the production process of high temperature puffing, and has made many guidances in actual manufacturers, and accumulated some technical parameters and experience. This paper analyzes the process of puffing processing through various steps in the production process.
Process and equipment
First of all, from the process flow, the raw material mixing - cooking agitation - roll pressing - reel - cooling aging cutting forming a drying - storage - secondary drying - frying / baking / frying plus seasoning - packaging - finished products. According to the process flow, the equipment is arranged such as a mixer, a skin press, a cooling machine, a rolling machine, an aging room, a forming machine primary dryer, a secondary dryer, a fryer and a seasoning machine.
The puffing effect of high temperature puffed foods depends on many aspects. For example, the content of amylopectin in the starch raw material, the more the content, the better the expansion; the internal moisture content and the degree of crystallization in the semi-finished product; the semi-finished product heating and drying stage, adding the leavening agent, partially decomposing and forming a very fine in the semi-finished product. The pore-like loose structure, the remaining leavening agent is thermally decomposed to produce gas, and the two synergistically act to make the product reach a fully expanded bulky structure.
Process parameters and analysis of each process
Raw material ratio. The raw materials are mainly starch and flour. The higher the starch content in the starch, the better. The proportion of amylopectin in each of the commonly used raw materials is sequentially decreased, and the degree of expansion is also sequentially decreased. The most common raw materials in the market are ranked, the best expansion is glutinous rice, followed by potato starch, tapioca starch, glazed rice, corn starch, and stalked rice. The flour is preferably medium gluten content (about 25% wet gluten content). The gluten content is too high, and the shrinkage elasticity of the gluten makes the product not easy to puff and cause collapse and stiffness; the gluten content is too low, and the dough is easily broken when rolled.
Based on actual production experience, two ingredients are recommended.
Option 1: 20% glaze rice, 80% potato starch, appropriate seasoning, appropriate amount of leavening agent (1% to 3%).
Option 2: 35% tapioca starch, 35% corn starch, 30% flour, appropriate amount of seasoning powder, appropriate amount of leavening agent (1% to 3%). In the scheme 1, the amount of glaze added should not exceed 20%, otherwise the degree of product expansion will decrease more. The following is a step-by-step analysis:
Stir in the cooking. The raw material is stirred with water and heated by steam. The steam pressure is generally 0.2 to 0.4 MPa, and the moisture is controlled to be about 40% after 4 to 5 minutes of cooking. Pay attention to steaming and stirring to make the starch fully gelatinized (α).
Rolling. The cooked dough is heated and rolled to form a dough of 1 to 3 mm thick, and the gap of the press rolls is 0.5 to 2.5 mm, and the gap requirements at both ends are the same.
reel. The roll was pressed and cooled by a cooling machine, and rolled into a roll of about 350 mm on a stainless steel pipe by a roll machine.
Cooling aging. The dough roll was placed in a warehouse at 20 ° C or lower (optimum temperature 3 ° C to 6 ° C) and relative humidity 50% to 60% for 24 hours to age (motherify) the starch.
Cutting and forming. The aged dough is embossed and formed on the molding machine according to the required specifications.
Dry once. The temperature is between 50 ° C and 60 ° C for 1.5 to 2 hours. After drying, the water content is reduced to 15% to 20%. At this time, the surface of the semi-finished product has formed a lattice structure, but the internal moisture is large, and no lattice structure is formed. If the moisture is too high after drying, on the one hand, it is easy to mold during storage, on the other hand, it does not achieve the purpose of crystallizing the surface of the drying surface; if the moisture is too low, the surface is over-crystallized, so that the water is not easily penetrated evenly. The difficulty of secondary drying is increased, resulting in uneven expansion.
Store. The storage is to make the water inside the semi-finished product permeate out and distribute evenly, which is beneficial to the secondary drying and puffing uniformity. Storage time should be more than 24 hours, so that the semi-finished products are soft and not easy to break.
Secondary drying. The temperature is 70 ° C ~ 80 ° C, time 6 ~ 8 hours, the moisture should be controlled to about 8% after drying. The test confirmed that the moisture content of the semi-finished product is closely related to the degree of expansion. If the moisture is too high, the instantaneous moisture cannot be vaporized, resulting in poor puffing, not crispy mouthfeel and sticky teeth; and if the moisture is too low, the amount of water vapor formed is insufficient, and the puffing is also poor. After the second drying, the interior of the semi-finished product is fully crystallized, and the moisture is evenly distributed in the crystal lattice.
Deep-fried/fried and puffed. Deep-fried with brown oil, oil temperature 190 ° C, time 6 ~ 8 seconds; fried with edible salt or food-specific grit as a heat transfer medium. Time 20 to 25 seconds. The temperature at the time of expansion is related to the degree of expansion of the finished product, and the temperature is 200 ° C to 210 ° C.
The quality of high-temperature puffed foods is closely related to the selection of raw materials, the drying moisture control of semi-finished products and the puffing temperature.
Analysis of cases of soybean puffed products
Eyes are directed towards the development of plant proteins. In developed countries, people's fear of cholesterol in animal foods and the latest nutrition and epidemiological studies show that soy foods have the health benefits of lowering cholesterol and preventing cancer. Therefore, the research and development of soybean food is constantly strengthening and deepening.
The following is a brief introduction to the production process of soybean puffed food.
soak. The soybeans are soaked in three times their own weight of tap water or 0.5% sodium bicarbonate solution. Depending on the season, the soaking time varies from 8 to 16 hours, and the soaking degree is about 2.2 times the original weight. Then rinse and drain.
Pulping. In order to prevent the soybean from being broken, a hot grinding method is adopted, that is, the whole soybean is mixed into clean hot water of 85 ° C to 90 ° C, and then ground into a slurry by a beater. The ratio of soybean to hot water is 1:6-7. Then, the ground slurry is separated, and the bean dregs are removed to obtain a soy milk-like product.
modulation. The soy milk was heated and maintained at 75 ° C to 80 ° C, then calcium sulfate was added in a ratio of 0.2%, mixed and allowed to stand for 10 minutes to coagulate the soy protein to obtain a tofu-like product. Since the digestibility of tofu is 92.7%, which is higher than that of other soybean products (such as cooked soybeans), the digestible rate of the puffed food made from tofu is also increased.
Add puffing aids and flavorings. In order to improve the puffing performance and nutritional quality of the product to enhance its taste and flavor, the following substances may be added in an appropriate amount:
1. Add a certain amount of starch, such as tapioca starch, to increase the expansion rate of the product.
2. Because soybean protein lacks sulfur-containing amino acids, the protein of rice crops such as rice and wheat lacks lysine. Therefore, if the two are mixed, the protein amino acid components in the mixture can be complemented, thereby improving the protein physiology of the product. Potency or bioavailability. It is advisable to add it evenly after grinding into powder.
3, improve the flavor of the product can add a little white sugar, onion and Garlic powder into.
Paste drying technology. The tofu was mixed with the above three substances in a certain ratio, and then heated in a microwave oven for 1 minute, and then steamed for 15 minutes to carry out gelatinization. The gelatinized mixture was cooled to room temperature, cut into thin sheets, and dried at 50 ° C for several hours to prepare a semi-finished product similar to shrimp slices.
Secondary expansion treatment. The above-mentioned semi-finished product is subjected to microwave or deep-frying (180 ° C to 190 ° C, 6 to 10 seconds) to puff, and a crispy and delicious soybean puffed food can be obtained. The excess oil after frying can be wiped off with a clean absorbent paper towel.
Product packaging. The puffed food was packaged in a linear low-density polyethylene film or aluminum foil and stored at room temperature for 10 weeks. The brittleness and moisture content of the product were measured every 2 weeks. As a result, it was found that the packaged expanded soybean food did not change in quality after being left at room temperature for 6 to 8 weeks.
Cling Film Wrap,Cling Film,Chinese Vegetables,Fresh Fruit
Toboli International Trading Co., Ltd. , http://www.jnapplefruit.com