Investigating the Influence of Drying Methods on the Quality and Bioactive Properties of Hemp ( <scp> <i>Cannabis sativa</i> </scp> L.) Seed Oil

This research investigates how oven and microwave drying methods influence mass reduction, oil yield, chemical composition, and bioactivity of <i>Cannabis sativa</i> seed oil, from two <i>C. sativa</i> L. varieties-Beldia and Critical-grown in Ketama and Taounate, Morocco. Microwave drying resulted in greater mass loss (2.1%-1.8%) compared to oven drying (1.48%-1.1%), but reached moisture stabilization within just 25 min, significantly faster than the 21 h needed for oven drying. Drying enhanced oil yield, with the highest recorded at 23.12% in oven-dried Ketama Critical seeds and 23% in microwave-dried Taounate Critical seeds, whereas untreated seeds yielded between 18.75% and 20.36%. GC-MS analysis identified linoleic acid as the predominant fatty acid, comprising 79.85% in fresh Ketama Beldia seeds and decreasing to 66.40% (oven-dried) and 79.27% (microwave-dried). Antioxidant capacity, assessed via the DPPH assay, peaked in the non-dried Ketama Beldia oil (IC₅₀ = 9.617 μg/mL), surpassing even ascorbic acid (IC₅₀ = 61.34 μg/mL). However, drying significantly diminished antioxidant activity, with IC₅₀ values rising to 31.185 μg/mL (oven), and 20.377 μg/mL (microwave). Antibacterial tests revealed inhibition zones ranging from 11 to 15.7 mm, with the microwave-dried Taounate Beldia variety showing the strongest effect. Antifungal assays also indicated improved activity post-drying, with a minimum inhibitory concentration (MIC) of 0.25% against <i>Geotrichum candidum</i> in oven-dried Taounate Beldia seeds. These findings highlight the potential contribution of Cannabis sativa seed oil to food security through its nutritional and bioactive properties.