Research On The Drying Technology Of Wolfberry, Antioxidant Capacity And Phytochemicals Of Wolfberry Brewed Liquid

Wolfberry is a long historical plant which has been enjoyed by people as natural health food for its benefits to liver and kidneys, to replenish vital essence, improve eyesight and strong bones. Fresh wolfberry fruit itself not storability, only up to3-4days. In this paper it started with the drying technology of wolfberry, based on the characteristics of Qinghai Plateau for its sufficient of solar radiation energy, based on the study of drying characteristics of wolfberry fruit a small scale solar drying equipment was designed. The test and applied the research of how to affect the different drying methods for the phytochemicals and antioxidant capacity of wolfberry was studied and compared to the traditional drying methods. The dried samples continue to applied for the research on the phytochemicals and antioxidant capacity of Wolfberry Brewed Liquid. The main research results are as follows:1) There are energy crisis all of the world and in order to make full use of the the characteristics of Qinghai Plateau for its sufficient of solar radiation energy, a small scale solar drying equipment was preliminary developed. The device structure and workflow features, computing of energy use, using characteristics and other aspects of reform recommendations was analysed。 The design of solar wolfberry drying device mainly consisted of thermal collectors, heat storage water tank, box-type drying oven, pipes and control system。 The test results of wolfberry drying shows that under the condition of no auxiliary heating to dry product was accomplished in the55h. Compared with the method than the traditional drying time was reduced to1/5.The utilization of solar energy was26.18%。 During the test, each part of the equipment to normal operation was achieved。 It is provides the basis for the application and feasibility of solar drying equipment for drying wolfberry production。2)The drying test which is open air drying, drying in shade and solar drying was studied on the Qinghai wolfberry fresh fruit and to compared the changes in environmental temperature and humidity, changes in moisture content and water activity, surrounding air speed, recording of the intensity of solar radiation and drying time, drying parameters of dried product, physical and chemical indicators, the phytochemicals and antioxidant capacity during the drying process。 The results suggest that water content of dried sample is about16%under the open sun drying about252h, drying in shade about274h and solar drying about55h. The color of sample dried in open sun drying method was darkled and not too full of texture while the color of sample dried in solar drying and dried in shade was bright red and full of texture. There is tissue deformation in open sun drying samples that easy to see deeply concave and the texture of samples are not uniform while the strip between the depth of dried in shade and solar drying samples was small and the texture was relatively uniform.Polysaccharides, carotenoids, ascorbic acid content and antioxidant capacity of dried in shade and solar drying samples were higher than that of open sun drying samples.3) One of the commonly uses of wolfberry is make tea drinking. In order to further defined the changes of phytochemicals and antioxidant capacity in the wolfberry brewed liquid under different condition so that aimed at provides the basis for the effect of wolfberry brewed liquid, the changes of phytochemicals,color shading and antioxidant capacity was studied after brewed liquid processing under different time, temperature and times. The results show that1) From60℃, L*value was decreased and b*value was increased of wolfberry brewed liquid with the increase of temperature and time. Antioxidant capacity was also increased until keep balanced after150min. Dissolution amount of polysaccharide was increased to90℃with the increase of temperature and time and keep balanced after150min while slightly get lower at100℃. The content of of carotenoids in the brewed liquid was very few. With the times of brewed liquid, L*value was increased and b*was decreased, other phytochemicals such as polysaccharides and carotenoids, antioxidant capacity was also significantly reduced.