Method for drying jujube sheets by using heat pump

Abstract

The invention discloses a method for drying jujube sheets by using a heat pump. The method comprises the following steps: washing the picked fresh jujubes, removing kernels, slicing jujubes into sheets with a slicing machine, injecting water and preparing into pulp powder by using a pulping machine, spreading on a smooth glass sheet for molding, and after solidification, and flaking by using a flaker to obtain the wet jujube sheets; conveying the wet jujube sheets spread on the smooth glass sheet to a drying chamber, heating the low-temperature air to be high-temperature low-humidity air by using the heat pump, conveying the high-temperature low-humidity air into the drying chamber by using an air blower for heating, and at the same time, dewetting and heating the low-temperature high-humidity air at the outlet of the drying chamber by using the heat pump and conveying the processed air to the drying chamber for circulation; slicing the dried jujube sheets and packaging to obtain the dried jujube sheet finished product. According to the drying method provided by the invention, the characteristics of being quick in dehumidification and energy-saving of the heat pump are used fully during low-temperature drying, and the problems of the conventional jujube sheet drying method that the period is long, the cost is high, the dried jujube sheets are poor in quality and large in loss of nutrients are solved; the original flavor of the jujubes is retained to the maximum extent; the dried jujube sheet finished product prepared by using the method provided by the invention is purely natural, safe and good for health.

Description

technical field [0001] The invention belongs to the field of drying fruits and vegetables, and in particular relates to a method for drying jujube slices with a heat pump. Background technique [0002] my country is a big jujube-producing country in the world, and the cultivated area of ​​jujube trees and the annual output of jujube account for more than 95% of the world's total. The sugar content of red dates is relatively high, the sugar content of fresh dates is about 19% to 44%, and the sugar content of dried dates is about 50% to 87%. The calorific value of jujube pulp per 100g is about 1293KJ, which is close to that of wheat flour (1427kJ), and contains 18 kinds of amino acids needed by the human body. At the same time, jujube is rich in various vitamins, especially the high content of Vc, so it is known as "vitamin pill". However, the biggest disadvantage of jujube is that it is easy to rot after being placed for a long time, and it is easy to be damaged during tran...

AI Technical Summary

Problems solved by technology

The natural drying method, commonly known as sun drying and air drying, is simple, convenient and low in cost, but it is easily restricted by natural conditions, especially in rainy weather, the drying process is prolonged and the quality of dried products is reduced

Artificial drying method is divided into hot air drying method, vacuum freeze drying method, microwave drying method, infrared drying method, etc. Hot air drying method is widely used at present, but in the drying process, it is prone to uneven drying and heat utilization rate. Not high, the problem of long drying time, and the high drying temperature in the oven will damage the nutrients in the jujube slices, and the loss of vitamins is large; vacuum freeze drying, microwave drying methods, high energy consumption, expensive equipment, and microwave drying Infrared drying method has the characteristics of fast heating speed, high heat transfer efficiency, and easy control, but the infrared coating is easy to age and fall off, and the emissivity will gradually decrease, and the thermal insulation requirements of the infrared dryer are relatively high. Strict, high cost, not economical

Images