The control of the oxidative stability of biodiesel and
blends
of biodiesel with diesel is one of the major concerns of the biofuel
industry. The oxidative degradation of biodiesel can be accelerated
by several factors, and this is most critical in the so-called second
generation biodiesel, which is produced from low-cost raw materials
with lower environmental impacts. The addition of antioxidants is
imperative to ensure the oxidative stability of biodiesel, and these
are considered products of high commercial value. The antioxidants
currently available on the market are from synthetic origin, so the
existence/availability of alternative antioxidants of natural origin
(less dependent on fossil sources) at a competitive price presents
itself as a strong business opportunity. This work describes and characterizes
a sustainable alternative to synthetic antioxidants used in the biodiesel
market developed from extracts of vineyard pruning waste (VPW), which
are naturally rich in phenolic compounds with antioxidant properties.
A hydrothermal extraction process was applied as a more efficient
and sustainable technology than the conventional one with the potential
of the extracts as antioxidant additives in biodiesel evaluated in
Rancitech equipment. The VPW extract showed comparable antioxidant
activity as the commercial antioxidant butylated hydroxytoluene (BHT)
typically used in biodiesel. The stability of the biodiesel is dependent
from the amount of the extract added. Further, for the first time,
the assessment of the environmental impacts of using natural extracts
to control the oxidative stability of biodiesel in the production
process is also discussed as a key factor of the process environmental
sustainability.