[Effects of fresh-cut on drying rate and quality of Panax notoginseng]

To study the effects of fresh-cut drying methods on the appearance and internal components of Panax notoginseng, and explore the feasibility of fresh-cut drying methods of P. notoginseng, so as to provide more effective processing methods for the production of P. notoginseng slices and Chinese patent medicines. In this study, we have compared the effects of 6 different drying methods on drying time, drying rate, density, appearance and internal components of P. notoginseng roots. It takes about 453 h to dry by whole-root drying in the sun, with a long constant speed period and a slow drying rate, the time of whole-root drying at 50 ℃ was shortened by 61.6% compared with whole-root drying in the sun, which resulted in the decrease of density and poor appearance of the medicinal material with hollow and crack appeared in the xylem, while the drying time of fresh-cut drying method was reduced by 61.82% to 91.58% and the drying rate increased greatly, due to the relatively slow drying process in the sun or in the shade after fresh-cut, salting-out and whitening appeared on the surface, and the internal components were all decreased to some extent. The drying time of fresh-cut drying at 50 ℃ was 91.58% and 68.83% shorter than that of whole-root drying in the sun and at 50 ℃, respectively. When drying at 50 ℃ after fresh-cut, the appearance and content of internal components of the medicinal materials were better, the appearance was yellowish green, the cut sections were clear with uniform pore distribution, and the content of saponin components was increased by 7.24% compared with that of the whole-root drying at 50 ℃, When drying at 40 ℃, the surface of slices has salting-out and whitening spots, and the loss of dencichine and total sugar was large, but at 60 ℃, this high temperature made the rate of dehydration of slices was extremely fast, which led to severe cracking and fragmentation, and the loss of total sugar and alcohol extract was large. By vacuum freeze drying after fresh-cut, the structure of medicinal materials slices was loose, the density was greatly reduced, and the appearance was different from those recorded in traditional books. The contents of total saponin components and dencichine were increased by 16.51% and 22.54%, respectively, compared with traditional whole-root drying. The fresh-cut process method is feasible in the production of P. notoginseng slices. In production, it is recommended that drying at 50 ℃ after fresh-cut can make the medicinal materials better in appearance and content of internal components, which is convenient for the subsequent processing and industrial feeding extraction. For the purpose of internal contents, it is better to adopt freeze-drying after fresh-cut processing method.