Hemp (Cannabis sativa L.) Varieties: Fatty Acid Profiles and Upgrading of γ‐Linolenic Acid–Containing Hemp Seed Oils

Abstract

Hemp seeds (HS) constitute a rich nutrient source and contain γ‐linolenic acid (GLA, 18:3, n‐6), which is a healthy fatty acid (FA). The objectives of this research are i) to look for GLA‐rich varieties of unhusked hemp seeds (UHS) and commercial hulled hemp seeds (HHS); ii) to check the influence of different extracting systems on both oil yield and FA profiles; iii) to test a simultaneous oil extraction/GLA‐enrichment process looking to improve GLA content. Hop and European hackberry seeds (both from Cannabaceae family) are also analyzed for comparative purposes. GLA is the most discriminant FA among UHS varieties, ranging in both UHS and HHS seeds from 0.5% to 4.5% of total FA, while hop seeds are the richest GLA source from Cannabaceae (7.2% of total FA). The extraction system selected for hemp seeds processing has a clear influence on oil yields, although, the FA profiles are slightly modified. The use of n‐hexane and n‐hexane:acetone in extractions allows an improvement in oil yields at the same GLA percentage. A process comprising saponification and subsequent cooling allows the improvement of GLA percentage in both hemp and hop seeds extracts at values higher than 10% of total FA, at high yields (>70%).Practical Applications: The global HS market increases significantly year after year and the demand of hemp products is increasing rapidly. The natural GLA sources in nature are limited, and although hemp contains GLA, this reaches low percentages in the oil. Hemp is a well‐established crop with highly standardized agricultural technologies, thus, the development of any well‐designed processes feasible for application in oil extraction industries, would allow the development of new GLA‐based functional seed oils. This would boost the development of the agricultural and food industries dedicated to revaluing hemp products.

Rare fatty acids and lipids in plant oilseeds: occurrence and bioactivity

“…Oenothera biennis L., evening primrose), Boraginaceae (Borago officinalis L., borage), Grossulariaceae (Ribes nigrum L. black currant), Malvaceae (Durio graveolens Becc. ), Cannabaceae (Cannabis sativa L., hemp) produce substantial amounts (7-20%) of this fatty acid as a constituent of their seed oils (PlantFAdb 2016;Guil-Guerrero et al 2001;Alonso-Esteban et al 2020;Kapoor and Nair 2020). In addition to higher plant species, γlinolenic acid has been also detected in animals, protozoa, fungi, algae and mosses.…”

HPLC Method for Separation of Cannabidiol Hemp Seed Oil with Skin Lipids and Tandem HRMS Technology for Characterization of a Chemical Marker

“…If all fatty acid chains have the same weight, its fragments A, B and C should have the same composition and fragmental weight. The TAG structure should have three similar linolenic fatty acid chains linked to glycerol, based on the hemp seed oil fatty acid profile reported in the literature [31][32][33][34]. If the red color fatty acid chain with three double bonds is changed into the two double bond structures, as in Figure 6, fragments A and B should have a weight of 597.4836 Daltons and fragment C should keep its weight at 595.4679.…”

“…If all fatty acid chains have the same weight, its fragments A, B and C should have the same composition. The TAG structure should have three similar linolenic fatty acid chains linked to glycerol, based on the hemp seed oil fatty acid profile reported in the literature [31][32][33][34]. However, if the red color linolenic fatty acid chain with three double bonds is changed into a linoleic chain with the two double bonds, fragments Furthermore, for the parent ion of 894.7525 with a retention time of 31.87 min, the fragmental ratio of 599.5014 and 595.4655 Daltons is 2:1.…”

“…However, if the red color linolenic fatty acid chain with three double bonds is changed into a linoleic chain with the two double bonds, fragments Furthermore, for the parent ion of 894.7525 with a retention time of 31.87 min, the fragmental ratio of 599.5014 and 595.4655 Daltons is 2:1. Using the same logical evaluation for the parent ion of 896.7682 with the retention time at 32.47 peak min, the TAG structure should have three similar oleic fatty acid chains linked to glycerol, as per hemp seed oil TAG chemical profiles in the literature [31,32]. A summary for those structural assignments is given in Table 2.…”

An ideal fatty acid composition for human health: Hemp (Cannabis sativa L.) seed

“…Ethanol (ET N = 0.654) and water (ET N = 1.000), the most polar solvents, obtained the lowest oil yields. In all extraction, the more polar the solvent, the lower the oil yield [21].…”