Batch Microwave Drying Machine
Ginger is the rhizome of Zingiber officinale Rosc, a perennial perennial herbal plant of Gingeraceae, and it is a widely used medicinal and edible plant. Because of its unique health function, ginger has developed many kinds of ginger food in recent years, such as ginger tea, ginger vinegar beverage, sugar and ginger, ginger rice, ginger sauce, etc.Among them, sugar and ginger is a popular food suitable for all ages. It can be used as leisure food, but also plays a certain pharmacological role.
Sugar and ginger are prone to browning in processing, which results in dark-brown products, which affects the appearance of products. Studies such as Mokaiju suggest that the main reason for browning is the oxidation of phenolic substances. However, during hot air drying, the color of sugar and ginger is deepened mainly by Maillard Reaction between amino compounds and reducing sugar, i.e. non-enzymatic browning. The reaction produces melanoids or melanoids, a brown or even black macromolecule substance. Drying temperature and time are important factors affecting the reaction. Therefore, reducing drying temperature and shortening drying time are important factors. Impedance of browning of sugar and ginger in drying process is an important way. Microwave vacuum drying is a new combined drying technology with the development of microwave drying technology. It can dry materials at lower temperatures, better maintain the nutrient composition of materials and improve the drying quality of products, overcome the shortcomings of conventional hot air drying for a long time and easy browning of products, and improve production efficiency and save energy.
The microwave vacuum drying of sugar ginger has not been reported yet. The continuous microwave vacuum drying process for lower sugar content raw materials such as leaves and fungus is different, and the sugar content of sugar ginger is higher. If continuous microwave drying is adopted, water molecules will vibrate at high speed after absorbing microwave energy and produce frictional heat instantaneously, while the high sugar content of sugar and ginger hinders the water migration, resulting in uneven heating of the product and the phenomenon of coke paste or even bursting. In order to make the drying medium heated uniformly, this experiment uses microwave generator multi-point stereo configuration and microwave real drying chamber structure optimization design. A new equipment of microwave vacuum drying is introduced. The discontinuous microwave vacuum drying technology of "microwave heating-intermittent-microwave heating" is used to explore the microwave vacuum drying mode and drying characteristics of avoiding tar paste, reducing browning and improving quality of sugar and ginger. The drying kinetics model of sugar and ginger is established to realize industrialized operation of high efficiency, energy saving and drying of sugar and ginger and microwave vacuum drying of high sugar products. Provide theoretical basis and technical support.
Effect of Intermittent Microwave Drying Time on Drying Rate and Quality of Sugar and Ginger.In different microwave heating-batch treatment, with the prolongation of microwave heating time, the drying rate of sugar and ginger increased and the drying time shortened, but at the same time, the coke paste rate of ginger increased, the color was darker, and the content of reducing sugar was high, which led to lower brittleness and sticky teeth.The raw material of wet sugar ginger is a cube. The length of the edge of ginger determines the volume and thickness of ginger. The volume or thickness of ginger has an effect on Microwave penetration and water escaping from ginger.
Intermittent microwave drying machine can avoid the occurrence of coke paste and browning. The suitable microwave heating and intermittence time are 30 and 90 s respectively. The power-mass ratio is 10-15 W/g and the vacuum degree is -80 kPa.