With respect to soxhlet extractions satisfactory yields (55–100%) were obtained for triglycerides.
Grape seeds and spent ground coffee provided the highest yields (85–100%) while hazelnut wastes provided the highest amounts of triglycerides (0.3–0.4 goil/gwaste).
Polyphenols were extracted from grape skins and seeds after adding a cosolvent (ethanol). Results showed that phenolic recovery was less efficient(11–25%) and that cosolvent amounts greater than 5% do not significantly affect the extraction yield.
Preliminary tests on grape seeds pointed out that a single supercritical treatment can be used for the fractionated recovery of triglycerides and polyhenols by changing the polarity of the solvent during the extraction process through the addition of a cosolvent.