Optimal drying method improving quality of Lycium barbarum L

Lycium barbarum L is the fruit with rich sweet and sour taste. It is not only the traditional medicinal material, but also a kind of nutritional supplement. Lycium barbarum L has seasonal and regional characteristics for harvest and short storage period. So the drying of Lycium barbarum L becomes a kind of important processing. At present, the drying of Lycium barbarum L is mainly traditional natural drying. This method needs long drying time and the mildew rate is high, so it has no guarantee to the quality of the products. It is difficult to meet the needs of the modern production. The drying in coal-fired drying room needs high energy consumption and produces severe pollution during the drying process. The temperature and humidity is not easy to control. The fireworks affect the quality of the dried Chinese wolfberry seriously. The solar drying equipment appears in Ningxia region in recent years. It uses solar energy and electrical energy to dry Lycium barbarum L. It is able to not only save energy and protect environment but also dry fast. The Lycium barbarum L was dried by natural drying, coal-fired drying room and solar drying equipment separately, and the drying rates of Lycium barbarum L were compared by weighing method. Their main functional components were measured and analyzed through the variance. The appearance quality and the rate of sugar were measured and analyzed as well. The fresh Lycium barbarum L was soaked by 5% sodium carbonate solution. Three wire weighing boxes were for a group and put in the coal-fired drying room, the solar drying equipment and the yard of cooperative separately. It was weighed once every 2 hours until it reached the standard of drying. The drying time of the 3 methods was recorded. The test results showed that the drying time of the natural air drying was about 78 h and that of the coal-fired drying room was 34 h. The shortest drying time of the solar drying equipment was about 26 h. The results showed that the content of the main functional components of Lycium barbarum L by the solar drying equipment drying was the highest, and it was about 71.77 g/(100 g). The main functional components of Lycium barbarum L by the coal-fired drying room was about 64.59 g/(100 g), and that by the natural drying was the lowest, about 57.84 g/(100 g). The Colourimetry was used to measure the color of the dried Lycium barbarum L. The results showed that the color and lustre of dried Lycium barbarum L by the solar drying equipment was the closest to that of fresh Lycium barbarum L. The color and lustre of dried Lycium barbarum L by the natural drying was the worst. The lowest syrup yield of dried Lycium barbarum L was obtained by the solar drying equipment, and it was about 1.533 g/(100 g). The highest syrup yield of dried Lycium barbarum L was obtained by the natural drying, and it was about 6.739 g/(100 g). ©, 2015, Chinese Society of Agricultural Engineering. All right reserved.