Characterization of Byproducts Originating from Hemp Oil Processing

Valorization of hemp seed meal, a byproduct of hemp oil processing, was performed by measuring the distribution of nutritional and antinutritional compounds in different hemp seed meal fractions. According to chemical composition, two cotyledon-containing fractions (>180 and <180 mu m) were significantly richer in protein (p < 0.05) (41.2% +/- 0.04% and 44.4% +/- 0.02%, respectively), lipid (15.1% +/- 0.02% and 18.6% +/- 0.04%, respectively), and sugar content (4.96% +/- 0.11% and 3.46% +/- 0.08%, respectively) in comparison to the hull-containing fractions (>350 and >250 mu m), which were significantly richer in crude fiber content (29.5% +/- 0.04% and 21.3% +/- 0.03%, respectively). The free radical scavenging capacity (IC50) of fraction extracts increased (p < 0.05) with increasing mean particle size (from 17.18 +/- 0.59 to 5.29 +/- 0.30 mg/mL). Cannabisin B and N-trans-caffeoyltyramine were the most abundant phenolic compounds in the hull fractions (from 267 +/- 15.9 to 287 +/- 23.1 mg/kg), while cotyledon fractions had higher content of catechin (from 313 +/- 12.4 to 744 +/- 22.2 mg/kg) and p-hydroxybenzoic acid (from 124 +/- 6.47 to 129 +/- 8.56 mg/kg (P < 0.05). Well-balanced pi-6 to pi-3 fatty acid ratio (3:1) was determined in all fractions. Antinutrients (trypsin inhibitors, phytic acid, glucosinolates, and condensed tannins) were mostly located in the cotyledon fractions. These findings indicate that the separation of hemp seed meal into different fractions could be used to concentrate valuable target compounds and consequently facilitate their recovery.