Postharvest blanching and drying of industrial hemp (Cannabis sativa L.) with infrared and hot air heating for enhanced processing efficiency and microbial inactivation

Abstract

Postharvest blanching and drying of industrial hemp (Cannabis sativa L.) by infrared (IR) and hot air (HA) heating was studied. Experiments were conducted at different IR heating times (1 and 2 min) and HA temperatures (65 and 85 °C) and compared with conventional indoor drying. Drying time was decreased from 3366 min (conventional) to as low as 222 min (85 °C HA). IR and HA processing reduced the total aerobic bacteria, and total yeast/mold levels by up to 0.81 and 1.85 log CFU/g, respectively from their initial levels of 4.63 and 4.75 log CFU/g, meanwhile reduced the activities of polyphenol oxidase and peroxidase by up to 91.7% and 66.7%, respectively. More than 96.1% total cannabidiol was preserved by thermal processing. Total terpene retention ranged from 18.3% to 71.1% under tested conditions with distinct terpene profiles. The results provide important information on the microbial safety and a timely solution to improve the postharvest processes of hemp.

Keywords:

• Postharvest technology
• blanching
• cannabidiol
• disinfection
• drying
• industrial hemp

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.

Additional information

Funding

The authors would like to thank the support from the University of California Davis Cannabis and Hemp Research Center.