Description
In 2021 10 varieties of Cannabis sativa (Carmagnola, Carmagnola CS, Jubileo, Fedora, Felina 32, Finola, Futura 75, Santhica 27, Uso 31 and Zenit) were tested in the field for the production of seed to be used for the extraction of edible oil and for the production of cake for livestock use.
Seed samples from the trial and commercial seeds were subjected to a cold pressing process using an auger press that yielded oil and cake with a residual fat content ranging from 4% to 10% (w/w).
61 samples of cake were ground to an average diameter of 2 mm and subjected to extraction in a ratio of 1:9 with an extracting solution (EtOH 50%/HCl 0.05 N for hydrophilic molecules, ethanol and acetone in a ratio of 1:1 for lipophilic molecules). The antioxidant activity of the extracts was tested on the free radical DPPH by recording its absorbance at 517 nm after 180". The activity of the hydrophilic extract is probably related to the high concentration of lignans in the cake (from 4466 ppm to 11692 ppm) while the activity of the lipophilic extract is mainly due to tocopherols (from 0.91 ppm to 1.47 ppm).
Spectra were acquired in diffuse reflectance with a NIRFLEX 500 Buchi spectrometer.
The predictive models developed showed a good predictive ability of the antioxidant power of the hydrophilic fraction (r2 cv= 0.91, RPD= 3.42 and RER=10.83). The results showed that the variety characterized by higher antioxidant power is Fedora, while those with lower antioxidant power are Finola and Carmagnola CS, characterized by higher oil yield (from 26% to 29%). Predictive models for the antioxidant power of the lipophilic fraction showed lower performance (r2 cv= 0.50, RPD= 1.41 and RER= 5.44) perhaps due to the reduced range of variation of concentrations in tocopherols because of the reduced content of residual oil.
