quickly), and inC. sativahas very minor market significance, although of con-
siderable interest biologically and medically. (2) “Hashish oil” refers to
solvent-extracts rich in THC, employed as a highly concentrated form of marijuana
(“liquid hemp”is a recent expression referring particularly to CBD-rich concen-
trates, especially for vaping). (3)“Vegetable oil”is“fixed”(meaning it is relatively
stable). Fixed oils are basically triglycerides, and are non-volatile at room tem-
perature, although they do evaporate very slowly, unlike components of essential
oils which evaporate rapidly. The edible vegetable oil ofC. sativa, i.e.“hempseed
oil”from the seeds, is the subject of this section. The phrase“hemp oil”should be
avoided because it could refer either to vegetable oil or essential oil. The phrase
“cannabis oil”could refer to either of these or to hash oil, and so is particularly
ambiguous. To avoid misinterpretation, the oilseed industry prefers the phrase
“hempseed oil”rather than“hemp oil.”Although“hemp seed”and“hemp-seed”
are often encountered,“hempseed”is the preferable spelling, in parallel with other
oilseed crops such as linseed and rapeseed.
Cannabis sativais employed as a source of a multi-purposefixed vegetable oil,
obtained from the“seeds”(fruits, technically“achenes;”Figs.1.3and1.5d). The
true“seed”portion is enclosed within the fruit wall (pericarp), which forms the
protective“hull”or“shell.”Most of the seed isfilled by an embryo, principally the
two cotyledons, which are rich in oils, proteins and carbohydrates, upon which the
germinating seedling relies for nourishment. A rudimentary nutritive tissue (en-
dosperm, rich in aleuron bodies, which are protein storage organelles) is also
present.
In recent decades the seeds have become an important source of edible oil.
Although oilseed use was relatively unimportant historically compared tofiber
applications, the commercial products made from hempseed have much greater
significance and potential today than thefiber usages. Moreover, the seeds of
C. sativaare increasingly being recognized as a legitimate source for medicinals,
nutraceuticals (nutritional extractives) and functional (i.e. nutritionally fortified)
foods. Indeed, while“medical marijuana”is widely (with justification) held to have
impressive therapeutic potential,“medical hempseed”also has remarkable thera-
peutic capacities.
1.6.3.1 Historical Review
Cannabisseeds were discovered in Chinese tombs over 4500 years of age (Jiang
et al. 2006 ), and have been employed for at least 3000 years as food for both
humans and livestock (Schultes 1973 ). Indeed, hempseed was one of the“five
grains”of ancient China, along with foxtail millet, broomcorn millet, rice, and
barley or wheat (Huang 2000 ), and remained a staple until the tenth century, when
other grains became more important (Cheatham et al. 2009 ). Archaeological evi-
dence for the food use of hempseed in ancient times in Europe is very limited, but
given the existence of traditional European hempseed recipes, it seems that for at
least centuries the seeds were employed for food to a minor extent (Leson 2013 ).
1 Classification ofCannabis sativaL. in Relation... 17