Effect of Selected Drying Methods on the Cannabinoid Profile of Cannabis sativa L. var. sativa Inflorescences and Leaves

The hemp industry uses traditional drying methods based on ambient temperature. However, these methods do not guarantee a high-quality dried product due to the possibility of mold growth. The present study aimed to evaluate the effect of the drying method for parts of the Cannabis sativa L. var. sativa plant (ambient temperature drying without light, freeze-drying, and convective drying at 50, 60, and 70 degrees C) on the content of 17 cannabinoids. The leaves were separated, and the inflorescences were subdivided according to size. Analyses were performed using UHPLC-HESI-MS. Traditional drying of the inflorescences increased the total cannabinoid content to 17.608-22.209 mg/g DM relative to fresh material (8.562-11.386 mg/g DM). Increasing the drying temperature by 10 degrees C significantly enhanced cannabinoid degradation in the dried inflorescences. The most significant increase in cannabidiol and A9-tetrahydrocannabinol content in the inflorescences was observed during traditional drying (up to 10 times). The greatest decrease in the content of the main acid precursors of cannabinoids, i.e., cannabidiolic acid and A9-tetrahydrocannabinolic acid A, was observed during convective drying (up to 3 times). The present study is one of the first to compare the effects of drying methods on the profile of cannabinoids in selected parts of the Cannabis sativa L. plant.