Produce high-quality crisp biscuits. Dough preparation is one of the most critical processes. Crispy dough requires good plasticity and cohesiveness. Almost no ductility and elasticity. Dough is binding and will not spread after forming. Non-stick mold. The formed blank should have good pattern and pattern retention ability. Don't deform when baking. Moderate spread. The finished product has clear patterns. The temperature of the prepared crisp biscuit dough is close to or lower than normal temperature. Usually called cold powder.

So as to minimize the formation of glutenin. Crispy dough is usually prepared in two steps. First, put all the raw materials except flour into a special mixer. Stir slowly for a few minutes. Its function is to dissolve as much sugar as possible with limited water consumption. Uniformly disperse and dissolve the milk powder. Chemical leavening agent and solid flavors and fragrances. Forming a uniform emulsion system. Sometimes it is necessary to add monoglycerides or phospholipids to the formula to help form a uniform emulsion system. Then add the flour. On the premise of ensuring the uniform mixing of various raw materials. Shorten the modulation time of the second stage as much as possible. The two-step dough preparation method uses the anti-gluten hydration of sugar and oil to inhibit the formation of gluten. Sugar dissolves to form a solution with a certain concentration. In this solution, water molecules are bound by sugar molecules. Reduce hydration with hydrophilic groups of gluten. Thereby reducing the formation of glutenin. When dispersed oil is mixed with flour. Oil can be adsorbed on the surface of flour particles. Form an oil film. Hinder the contact between water molecules and gluten protein and the expansion of gluten network.

The requirements for making crispy dough are very strict. A little more water or a little longer stirring time may lead to the deterioration of dough quality. Therefore, it is very important to correctly judge the key points of dough making. Pay attention to the following points when preparing pastry.

① Water addition and dough mixing time: The specific water addition in actual production depends on the protein content of flour and the formula of biscuits. Under normal circumstances. Add more water. Soft dough tends to form gluten. Therefore, the mixing time is shorter. On the contrary, dough with less water content should be stirred for a longer time. Otherwise, the adhesion of dough is poor. The dough has poor formability. Generally speaking. The moisture content of pastry dough is 16% ~ 18%.

(2) Mixing temperature: generally, water temperature is used to adjust the milling temperature. The stirring temperature of crisp dough is generally controlled at 22 ~ 28℃. But if the temperature is too low for dough with less oil content. Will make the dough more sticky. Not conducive to operation. On the contrary. If the dough temperature is too high. It also hardens the dough. Resulting in shrinkage and deformation. Therefore, dough with less oil content. The temperature should be controlled below 30℃. Suitable for dough with high oil content. The temperature is generally controlled between 22 ~ 26℃, because the high oil content reduces the viscosity and binding force of dough. This has a bad influence on operation and biscuit quality.

③ Standing: If gluten formation is insufficient during preparation. Proper standing is a remedy. Because at rest, the hydration of gluten proceeds slowly. Thereby reducing the cohesion of the dough. Increase flexibility. But if you let it stay too long. More water is absorbed by gluten and starch. The dough became dry and hard. Cohesion decreases. Loose organization, unable to operate. Theoretically speaking. Crispy biscuits can be formed by roll printing, steel wire cutting, extrusion, roll cutting and so on. However, due to the high proportion of oil and sugar in the pastry. Roller printing is the most widely used in practical production. Add the prepared crisp dough into the feed hopper of the drum printing forming machine. Driven and squeezed by the feed trough roller. The material enters the mold of the mold roll and is compacted. The scraper attached to the surface of the molding roll scrapes off the material protruding from the mold. Forming a neat blank bottom surface. With the further downward rotation of the molding roll. The biscuit blank touches the canvas conveyor belt running horizontally below. And demoulding under the action of a rubber demoulding roller. Conveyed by canvas conveyor belt to steel wire mesh conveyor belt and baked in oven.

In the process of roll printing. The position of separating scraper affects the quality of biscuit blank. When the position of the edge of the scraper is high, the material protruding from the mold cannot be completely removed. Thereby improving the quality of a single biscuit blank; When the position of the cutting edge is low. The quality of biscuit blank will decrease. The position of edge scraping should be 2 ~ 5 mm below the center line of the die roll.

In order to make the biscuit blank leave the die roll smoothly. A good balance should be established between the adhesiveness of dough, the adhesiveness of canvas conveyor belt and the pressure of rubber demoulding roller. The adhesion of canvas conveyor belt is too poor. Biscuits can't stick to the conveyor belt. Causing difficulty in demoulding; If the cohesiveness of the dough is too poor. When biscuit blank is not in contact with canvas conveyor belt. Under the action of its own gravity, it will leave the mold. Resulting in deformation of biscuit blank. Crispy dough will form a solid if it is too soft. Resulting in insufficient feeding. It is difficult to demould. The dough is so soft that sometimes the scraper can't scrape off the extra crumbs on the biscuit surface. Causing the tail edge phenomenon. Affect the appearance of biscuits and subsequent finishing and packaging. If the dough is too hard. This will also make the dead weak. Resulting in difficult or incomplete demoulding. There are cracks on the surface of the finished biscuit. The crushing rate increases. The pressure of rubber demoulding roller also affects the demoulding quality of blank. If the pressure is too small. There will be a roll sticking phenomenon; If the pressure is too great. Will make the biscuit blank uneven in thickness. Even deformed. On the premise of making the biscuit demould smoothly. Minimize the pressure of the demoulding roller. Because the recipe of crispy biscuits contains more oil and sugar. There is less bonding in the dough. Therefore, the moisture in the dough is easy to evaporate. Therefore, the baking process of "higher temperature and shorter baking time" is often used in the baking of crispy biscuits. After the green body enters the oven. In the expansion and solidification stages, higher primer and surface fire temperature are needed. So as to rapidly solidify the green body. Prevent the phenomenon of "oil dispersion" caused by too much grease in the formula. After that, the baking temperature should be gradually reduced. Because the formula of crispy biscuits generally contains more sugar and milk powder. So the baking temperature in the back zone must be low. Prevent the surface from over-coloring. In actual production, the appropriate baking temperature can be selected according to the product formula, biscuit blank size and hardness. Generally speaking. The temperature at the front of the oven is 250 ~ 280℃. The temperature in the central area is 220 ~ 240℃. The temperature in the back zone is 180 ~ 200℃. At this baking temperature. The baking time is 5-6 minutes.

When baking, the crisp dough with high fluidity must use smooth low carbon steel conveyor belt. Products with relatively low oil content and sugar content are mainly baked on low carbon steel mesh belt. The mesh belt has good heat transfer speed. So baking is faster. But dough tends to fall into the grid. This will cause serious damage to cookies at the end of the oven. And it will pollute the mesh belt. Therefore. After the biscuits pass through the oven continuously. When it is unloaded from the conveyor belt, there will be black and burnt particles on its bottom surface.

The "scattering" of crisp biscuit blank during baking is the most common problem in production. Excessive smearing not only affects the appearance of biscuits. But also increase the breakage rate of biscuits during processing and packaging. There are many factors that affect biscuit spreading during baking. Here, the factors of increasing dispersion and decreasing dispersion are introduced respectively. Factors that increase dispersibility include coarser flour particles. After adding flour, the brewing time in the second stage is shorter. The average particle size of sugar is very small. There is more crystalline sugar. More fat. Because the brewing temperature is too high, the dough becomes soft. Use more leavening agent. The quality of biscuit blank is too high. Oil the conveyor belt of the oven. Cookies are placed on the conveyor belt of the cold oven, and the temperature in the front of the oven is very low. Factors that reduce dispersibility include the high water absorption of flour. The dough is overcooked. Low sugar content and large average particle size. Low fat content. The dough preparation temperature is low. The biscuit blank is of poor quality. The oven was dusted. The temperature in the oven is very high. Quick baking, etc. In production practice, corresponding adjustments can be made according to specific conditions.

Due to the melting characteristics of sugar. The biscuit blank is soft when it leaves the oven. Before finishing and packaging. Must be thoroughly cooled. The adopted method can prolong the cooling conveyor belt of biscuits. The length of the cooling conveyor belt is generally greater than 1.5 times the length of the oven. But the cooling zone is too long. Uneconomical. Take up space and ask again. Biscuit blanks can also be forced to cool by blowing. The suitable cooling condition is 30 ~ 40℃. The relative humidity is 70% ~ 80%.