The subcritical water extraction (SubWE) kinetics of sunflower
oil and the comparison to extraction kinetic curve obtained by
Soxhlet extraction are presented in Fig. 1a. Results show that for
the SubWE the highest oil yields (gOE) are achieved at an extraction
temperature (Te) of 130 C and a material to solvent ratio (M/S) of
1/20 g/mL, with a maximum yield of 44.3 ± 0.3% after 30 min of
extraction, giving comparable results to those obtained after 4 h
by the Soxhlet (46.2 ± 0.7%). At 160 C a similar maximum
(43.9 ± 0.3%) is achieved for SubWE but after 2 h of extraction. At
other applied temperatures and M/S ratios lower yields are
obtained. Increasing temperature hence improves the extraction
yield of SubWE as was predicted. It can be also observed that at
all conditions investigated, except at 160 C, the extraction rates
are much higher compared to Soxhlet extraction. The highest oil
yields are obtained in te 6 30 min, while in the case of Soxhlet
extraction the time needed is 4 h.