Advances in drying technology of jujube
[abstract] Drying is one of the deep processing methods in jujube industry. In this paper, the research status of several main microwave drying equipments for jujube in China was introduced. The drying principle, system composition and technical characteristics of these equipments were expounded. At the same time, the future development trend of jujube drying technology in China was pointed out.
[keywords] jujube microwave drying; drying technology; research status; development trend
Red jujube, also known as Chinese jujube, jujube and spine jujube, is the mature fruit of jujube tree of Rhamnaceae. Jujube is sweet and unique in flavor. It not only contains rich nutrients, but also has the earliest medical and health value in China. It is often used in traditional Chinese medicine. It has the functions of tonifying blood and qi, anti-cancer, brain-strengthening, protecting liver, detoxifying drugs and stomach, strengthening spleen and body.
As a unique fruit and vegetable resource in China, jujube has absolute advantages in planting area, variety and yield. At present, China has the vast majority of the world's excellent varieties of jujube, and the output of jujube accounts for about 95% of the world's total output, planting area is wide, mainly distributed in Shanxi, Hebei, Shandong, Shaanxi, Xinjiang and Henan.
In recent years, due to its special geographical location and environment, the jujube industry in Xinjiang has developed rapidly, and its jujube has gradually occupied the high-end market because of its high sugar content, large grains, thick flesh and beautiful appearance. Jujube contains many trace elements and rich nutrients, and has unique nutritional and medicinal value. However, fresh jujube can be stored in natural conditions for only a few days after harvest, and its pulp will quickly brown or rot.
Therefore, at present, the main products of Chinese jujube are dried jujube, and the proportion of dried jujube is more than 90%. In this paper, the working principle, technical characteristics, system composition and technical research status of several main drying techniques of red date were introduced, and the future development trend of red date drying technology was pointed out.
The drying technology of red date can be divided into two kinds: natural drying method and artificial drying method. Natural drying is the most traditional method of dry red dates, red dates is mainly to be dried by the sun light and natural wind. The common method of natural drying drying and dry dry dry. The sun is the dry jujube exposure Shaichang, jujube thickness was about 6cm, every once in a while turning once to make it uniform drying.
The sun dry dry red dates need about 10d time, its disadvantage is that in case of rainy days, especially the continuous rain days, there will be a lot of rotten red dates. Dry dry red dates is placed in dry, cool, ventilated place shelter and spread, turning once or twice every day, the fresh red dates water has lost gradually and become dry red dates. Dry dry dry red dates are not affected by the rainy weather, but the time required for about 30d, the same