This included data obtained from the
characterization of genes and enzymes related to fatty acid biosynthesis and triacylglycerol assembly.
Future improvements and uses of these oils are also discussed.
Introduction
1.1. Generalities
Sunflower (Helianthus annuus L.) is a plant of the family of the
Compositae (Asteraceae), belonging to the genus Helianthus. This
plant is an annual crop, having a large yellow inflorescence con-
taining small flowers that give rise to achenes containing a kernel
rich in oil. This plant was first domesticated and cultivated by
natives from Central and North America, and was introduced into
Europe by Spanish explorers in the sixteenth century. The cultiva-
tion of sunflower was extended all over the world during the 19th
and 20th centuries and is today the fourth largest vegetable oil
product (after palm, soybean and rapeseed) and, thus, an impor-
tant agricultural commodity. Today the main centers of production
of sunflower are the USA, Ukraine and Argentina.
Sunflower is cultivated in temperate climates (temperature
range between 20 and 25 °C). The plant grows better in dry cli-
mates with high solar irradiation and deep soils in which it is able
to develop its long root system. The seeds of sunflower are pro-
duced within an achene and consist of a shell composed mainly
of lignin and cellulose material and the kernel, which accounts
for 80% of the total weight of the seeds and is rich in oil (up to
55% dry weight). The final oil content of sunflower seeds is usually
around 50% w/w [1]. This oil is rich in linoleic acid, which accounts
from 48% to 74% of the total fatty acids. It contains low levels of
saturated fatty acids (mainly palmitic and stearic acids) and, unlike
other seed oils such as soybean and rapeseed, negligible amounts
of a-linolenic acid. The relative amount of linoleic compared to
oleic acid is very variable and is related to temperature regulation
of endogenous desaturases