DRYING KINETICS AND THE EFFECTS OF DRYING METHODS ON QUALITY (CBD, TERPENES AND COLOR) OF HEMP (Cannabis sativa L.) BUDS

Abstract

The hemp industry currently relies on traditional drying methods to preserve and extract the cannabidiol (CBD), but they do not allow a high-quality product. Therefore, effects of two drying technologies, convective drying (isothermal and non-isothermal), and freeze drying on the drying time and product quality (CBD, terpenes, color) were evaluated. An increase of the drying temperatures significantly decreased the terpenes content (above 40 ºC) but, it did not effect the CBD content. The total CBD content was the highest (2.78%) under non-isothermal drying condition (40 °C changed to 70 ºC at 25% moisture content) and was the lowest (1.28%) under freeze-drying. The proposed drying regime reduced the time by 90% compared to control (32 °C) and the CBD increased compared to the fresh material. This is by far the first report to show the behavior of CBD and terpenes as influenced by various drying temperatures and technologies in hemp buds.