3.3 Tocopherols
The individual tocopherols identified are showed in Table 3; a total of
49.8, 86.9 and 41.2 mg/100g of oil were quantified in F1, F2 and F3,
respectively; while a total of 94.8, 87.7 and 77.8 mg/100 g of oil were
quantified in C1, C2 and C3, respectively. It is recognized that
tocopherols are the most important natural antioxidants because of their
free radical scavenge activity, involving a tocopherol-tocopheryl
semiquinone redox system (Montserrat-de la Paz et al., 2014). In
addition they have shown different beneficial effects on degenerative
diseases such as atherosclerosis, cardiovascular disease, Alzheimer’s
disease and certain type of cancer (Fromm, Bayha, Kammerer & Carle,
2012).
As expected, considering the literature, in all samples γ-tocopherol was
the predominant compound followed by β-tocopherol, α-tocopherol and
α-tocotrienol. In Futura 75 γ-tocopherol showed a significative
increase (p < 0.05) between first and second harvest
(40.8 and 82 mg/100 g of oil in F1 and F2, respectively) and then
significantly (p < 0.05) decrease at last maturation
time (F3, 37.1 mg/100 g of oil). The other tocopherols were present in
very low concentration; in fact, β-tocopherol was present only at the
first harvesting stage (9.0 mg/100 g of oil) and α-tocotrienol just in
the last one (3.3 mg/100 g of oil). α-tocopherol were not detected at
first maturation stage, but only in the other two, with a significative
(p < 0.05) decrease between them, 4.9 and 0.8 mg/100 g
of oil for F2 and F3, respectively. For this reason, the total
tocopherols content had the same trend of γ-tocopherol, increasing
significantly (p < 0.05) the total concentration at the
second harvest stage (F2) reaching a value about 87 mg/100 g of oil
(Table 3). Also in Carmagnola γ-tocopherol was the predominant
tocopherol with a significative decrease (p < 0.05)
during the maturation, 90.2, 81.8 and 72.9 mg/100 g of oil for F1, F2
and F3, respectively. β-tocopherol, on the contrary, was not detected
during the entire maturation. α-tocopherol was present in every maturity
stage with a significant increase (p < 0.05) in the
middle of maturity; 3.5, 5.9 and 4.9 mg/100 g of oil in C1, C2 and C3,
respectively. Finally, α-tocotrienol was present just at the beginning
of maturity (C1) with a concentration of 1.1 mg/100 g of oil. Total
tocopherol concentration follows γ-tocopherol trend, so a constant
significative decrease during maturation was recorded; 94.8, 87.7 and
77.8 mg/100 g of oil in C1, C2 and C3, respectively.
Our results agree with literature where γ-tocopherol represent the 90%
of the total tocopherols content (Oomah et al., 2002; Anwar, Latif &
Ashraf, 2006; Latif & Anwar, 2009; Montserrat-de la Paz et al., 2014).
In a study conducted by Kriese et al. (2004), where hempseed oil was
extracted by supercritical fluids, the general tocopherol content was
much lower than ours, so, in addition to botanical characteristics,
climatic and cultivation conditions, also the extraction method affects
the tocopherols content.