Abstract:

Taking Guizhou Baphicacanthus cusia as the research object, the effects of 9 drying methods, including shade drying, sun drying, vacuum drying, 50 ℃ oven drying, 100 ℃ oven drying, freeze drying, hot air gun drying, microwave drying and microwave post drying, on leaf properties, effective components and β-glucosidase activity were investigated. The results showed that the dry leaves treated by microwave drying still retained green stretch state, uniform color and better appearance. The mass fractions of indigo and indirubin in the leaves of Baphicacanthus cusia dried in the oven at 50 ℃ were 0.68% and 0.051%, respectively, and β-glucosidase had higher activity (12.23 U/mg). The microwave dried Baphicacanthus cusia leaves had the advantages of good appearance and high mass fraction of indicant (8.84%), where β-glucosidase was almost completely inactivated. Therefore, the microwave drying technology could be popularized and applied in the drying process in the production of Baphicacanthus cusia.

Key words: Baphicacanthus cusia, drying methods, β-glycosidase activity, indican, indigo