Rice product microwave expansion equipment · <<上一篇 · Next>> · Source: Original · [Large, medium and small] · Click 34 times · Released: 2012-7-5    Microwave expansion is a new atmospheric expansion technology that uses microwave radiation to heat and vaporize the moisture in the material, thereby promoting the expansion of food materials. Microwave puffing, because of its fast heating speed, short heating time of food, compared with extrusion puffing and frying puffing, it is not easy to cause some unnecessary chemical reaction of food, and does not increase the fat of food, and retains the product better. The original flavor, so microwave puffing is widely used in starchy foods (such as corn, rice, millet), protein foods (such as soybeans), mixed foods (such as shrimp slices, etc.). The metric small food is a good application direction for microwave expansion. ã€Back】 ã€Back to list】 Previous: What is industrial microwave oven
1. General production process of microwave expansion of metric small food:
Rice - Soaking and Cooking - Extrusion - Refrigeration and Curing - Blanking - Drying - Microwave Puffing
2. Evaluation of microwave expansion effect:
   The evaluation index of the microwave expansion effect mainly refers to the size of the microwave energy required for the product to be puffed, the puffing rate of the food, and the quality of the puffed product itself. The amount of microwave energy required to puff the product is measured by the puffing time required at a certain microwave frequency. The expansion rate of the food is measured by the volumetric method of the product obtained by microwave expansion, and the expansion ratio is equal to the ratio (multiple) of the volume after the material is expanded to the volume before the material is expanded. The quality of the expanded product is evaluated by the crispness of the product, the flatness of the appearance, and the color.
3. Analysis of the influencing factors of microwave expansion effect:
   There are many factors that affect the effect of microwave expansion, but the overall can be summarized as raw material factors, equipment and operational factors and process factors.
1 raw material ratio
   The ratio of raw rice directly shows the ratio of amylopectin to amylose. Due to its high molecular weight, amylopectin can form a complex network structure in the process of cooking to slab. The combination can be more uniformly wrapped in the water absorbed during the soaking process; The structure is loose and the water absorption capacity is strong. Therefore, after the microwave expansion, the puffing property and the mouthfeel of the expanded product are good. Generally, the ratio of the amylopectin contained in the rice starch is about 95% after the ratio of the raw materials and the large materials, and the excessively high is unfavorable for the slab.
2 immersion time, the degree of ripening
   After the raw rice is fully immersed and cooked, the original raw starch is absorbed, and the original microcrystalline bundle structure is broken. The water molecules combine with the starch molecules to form an irregular, three-dimensional space with a large gap. grid. The formation of such a network structure has a great influence on the degree of expansion of the rice product. Under this structural state, the starch gel water molecules are evenly distributed, which is favorable for the uniform absorption of microwaves. The spatial network structure formed by the stretching and bridging of starch molecules increases the pressure-bearing capacity and enhances the puffing. The effect is that the taste of the rice product is better.
3 effects of extrusion
   After the ripening, the rice grains pass through sufficient erosion until the rice grains are not seen, and the purpose is to destroy the molecular agglomerate structure of the matured starch to form a complex network structure. Thus, during the drying process, although the matured starch molecules will again have a regular molecular arrangement, the binding force of the rearranged molecular group structure is much weaker than the original one. This can reduce the energy required to cleave the molecular mass.
4 Effects of refrigeration curing
   The preform after the gelatinization and extrusion molding is subjected to refrigerating and solidification in order to facilitate the operation of the preform. However, during the refrigeration curing process, the gelatinized starch is prolonged with the curing time of the refrigerator, and the degree of aging is increased. Starch aging produces crystals, which causes the amorphous zone to decrease, the water molecules of the material to be unevenly distributed, the starch material's own pressure-bearing structure to be destroyed, and the crystal's melting endotherm, which increases the microwave energy required for puffing, which is not conducive to microwave puffing. Will cause the expansion rate of microwave puffing products to decrease.
5 Influence of the geometric properties of the blank
   The small body is easy to be heated, and the penetration of the microwave is good, the heating is uniform, and the green body is large, especially when the volume of the green body is much larger than the wavelength, the outer layer of the blank is easily heated and may be coked. The center temperature is still very low, and the degree of puffing is not reached, and the phenomenon of "sanding" occurs. The uniformity of the green body also affects the extent to which the small volume of the green body first expands during the expansion process and the large volume of the green body still does not reach the degree of expansion.
   The shape of the blank: microwave is a kind of electric wave, and its electric field also has sharp angle concentration, that is, edge effect, which makes the temperature rise at the corners particularly fast, and even causes the scorching phenomenon after puffing. Therefore, sharp corners should be avoided when making quilts and blanks to prevent puffing.
6 The effect of moisture (drying) of the body
   The moisture of the green body is related to the crispness and appearance flatness of the rice puffed food, and is one of the important factors affecting the puffing effect. If the moisture is too high, it is difficult to discharge too much water in a short time, which results in a low degree of expansion of the green body, soft taste, and no crispness. If the moisture content of the green body is too low, it is difficult to puff during the expansion. Sufficient puffing internal pressure is produced in a short period of time, so that the degree of expansion of the product is lowered. Generally, the moisture of the green body is controlled at about 9%.
7 impact of puffing time
   The puffing time is also a very important factor affecting the puffing effect. The length of the puffing time is directly related to the crispness and color of the puffed rice products. Within a certain range, the degree of expansion increases with the expansion time, but if the puffing time is too long, the effect of puffing is not obvious, and the finished product will produce coking, so that the quality of the puffed product is reduced, and conversely, the puffing time is too short, the finished product Both the degree of expansion and the crispness are poor. The general puffing time is controlled at 2 min (frequency is 2450 MHz).
   As an application method of microwave technology, microwave expansion is more and more valued by small food manufacturers. With the deepening of research on microwave expansion technology, the application of microwave expansion will be more extensive.