Abstract

Drying is one of the most important post harvest processes, which convert decaying products to resistant preparations so that it increases the storage duration and keep product quality (food stuff shelflife). Hypericum perforatum L. is an important kind of herbs, which its Iranian species characterized by high percent of Hyperisin as the most important substance of its leaves and flower. It has an important role in curing some diseases. The aim of this research was to investigate the effects of the temperature fluctuations at four levels (40, 50, 60 and 70°C), air velocity at three levels (0.3, 0.7 and 1 m/s) and bed depth at three levels (1, 2 and 3 cm) of St. John’s wort leaves. A factorial experiment design was laid out in completely randomized design with three replications. In this research, the best treatment for drying time and rate of drying were obtained at temperature of 70°C, air velocity at 1 m/s and 1 cm bed depth.

Key words: Hypericum perforatum L., drying time, drying rate.