[Further promotion effect of variable temperature drying on effective components in roots of Salvia miltiorrhiza f. alba].

To study the effects of different variable temperature drying modes on active components of roots of Salvia miltiorrhiza f. alba, and provide basis for its industrialized drying process. In order to ensure the content of active components, variable temperature drying modes were designed: low temperature at 30 ℃ and high temperature at 60 ℃, low temperature at 30 ℃ and high temperature at 70 ℃, low temperature at 30 ℃ and high temperature at 80 ℃, low temperature at 40 ℃ and high temperature at 60 ℃, low temperature at 40 ℃ and high temperature at 70 ℃, low temperature at 40 ℃ and high temperature at 80 ℃ and air dry oven was used for variable temperature drying process. Then HPLC method was used to determine the changes of active components in roots of S. miltiorrhiza f. alba under different temperature modes; and SPSS 17.0 was used to analyze the data. The results showed that the samples, which were first dried at 40 ℃ for six hours and then dried at 80 ℃ for three hours, had the highest contents in dihydrotanshinone, cryptotanshinone, tanshinone Ⅰ and tanshinone ⅡA as compared with other kinds of drying methods, and the contents were 0.35, 2.76, 0.78, 4.47 mg•g⁻¹, respectively. Additionally, as compared with samples dried in the shade, the contents of dihydrotanshinone, cryptotanshinone and tanshinone Ⅰ were increased 2.9% (P>0.05), 45.3% (P<0.05) and 34.5% (P<0.05), respectively; however, the content of tanshinone ⅡA was decreased by 44.1% (P<0.05). The water-soluble active components (rosmarinic acid and salvianolic acid B) of roots of S. miltiorrhiza f. alba, had the highest contents when the samples were first dried at 30 ℃ for six hours and then 70 ℃ for three hours, and the contents were 3.83,55.44 mg•g⁻¹, increased by 62.3% (P<0.05) and 109.1% (P<0.05) respectively as compared with the samples dried in the shade. Variable temperature drying can significantly affect the contents of active components in roots of S. miltiorrhiza f. alba. As compared with the traditional process of shade-drying process, low temperature drying can significantly increase the content of water-soluble active components and also with significant promotion effect on the liposoluble components such as tanshinone ⅡA, cryptotanshinone and tanshinone Ⅰ. The variable temperature drying mode, can effectively shorten the process of drying and provide theoretical basis for industrial processing of roots of S. miltiorrhiza f. alba.