Spray drying is a drying method that uses an atomizer to disperse the raw material liquid into droplets, and use hot gas (air, nitrogen or superheated steam) to dry the droplets to obtain a product. The raw material liquid for spray drying may be a solution, an emulsion, a suspension, a molten liquid or a paste liquid. The dried product can be made into powder, granule, hollow sphere or pellet form as needed. Atomization of liquid The atomizer that disperses the material liquid into droplets is a key component of spray drying.
There are three types of spray dryers: pressure spray dryers, centrifugal spray dryers, and airflow spray dryers. The following briefly introduces the working principles of these three spray dryers:
1. Principle of pressure spray dryer:
Adopt pressure atomizer: Use a high-pressure pump to make the liquid get high pressure. When the high-pressure liquid passes through the nozzle, it converts the pressure energy into kinetic energy and disperses into droplets when it is sprayed at high speed.
2.Principle of airflow spray dryer:
Air-flow atomizer: compressed air or steam is sprayed from the nozzle at a very high speed (≥300 m/s), and the material liquid is split into droplets by the friction force generated by the speed difference between the gas and liquid phases .
3. Principle of centrifugal spray dryer:
Adopting rotary atomizer: the material liquid is thrown out from the edge of the disc and atomized by centrifugal force at a high-speed turntable (circumferential speed 90-160/ms).
Briefly describe how to optimize the spray dryer process to the problem of poor fluidity of ginkgo powder
Spray dryers are used in many fields such as food and medicine, but recently it has been discovered that many products can be atomized and dried by spray dryers. For example, the fluidity of ginkgo is relatively poor, and the effect of spray dryers is not ideal. The editor introduces you to the optimization of the process flow of the spray dryer for the poor fluidity of ginkgo.
Spray drying In the research of ginkgo, it is found that the fluidity and solubility of ginkgo powder are not very good, and the process needs to be improved. Adding maltodextrin, gum arabic or β-cyclodextrin and other additives to the ginkgo solution as auxiliary materials. Why choose these three excipients?
Maltodextrin is easy to disperse and dissolve in water, and has strong hydration power. Once the moisture is absorbed, the ability to retain moisture is stronger and increase the consistency. In addition, it can reduce obesity, hypertension, diabetes, etc. Adding maltodextrin to ginkgo can increase the solubility, improve the uniformity and viscosity of the solution. And the low sugar content is suitable for all kinds of people.
Gum arabic has a high degree of solubility. Normal gums can only be saturated by adding about 5-8% of colloid in the process of dissolving water. The mixing ratio of gum arabic to water can be as high as 60%. It can have very high viscosity performance at high content. In addition, it also has good emulsification and film-forming properties; as a microcapsule film-forming agent, it is used to convert essential oils or other liquid raw materials into powder form, which can extend the flavor quality and prevent oxidation. In terms of nutrition, arajiao basically produces no calories and is a good water-soluble dietary fiber, which is used in health care products, candy and beverages. In medicine, gum arabic also has the function of lowering blood cholesterol. The addition of gum arabic to ginkgo can not only improve the solubility, but also has the effect of anti-oxidation and lowering blood cholesterol after eating.
β-Cyclodextrin has a cylindrical structure. Its two ends and the outside are hydrophilic, while the inside of the cylinder is hydrophobic. Some molecules of suitable size and shape (such as halogens, volatile oils, lipids, etc.) are contained by van der Waals forces. In the ring structure. It is characterized by its inclusion effect, good dispersibility in water, and strong encapsulation of grease, increasing stability and solubility. Using β-cyclodextrin as an auxiliary material can enclose the oil contained in the ginkgo, which is not easy to damage, preserves the natural components of the ginkgo, and increases the dispersibility of the powder.
Therefore, three additives such as maltodextrin, gum arabic and β-cyclodextrin were selected as auxiliary materials to improve the solubility and fluidity of ginkgo powder for experimental research to determine the auxiliary materials and the best formulation for improving the fluidity and solubility of ginkgo powder. Ratio, so that the quality of the product can be improved without excessively increasing the cost of the product.