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Small Branches of Olive Tree: A Source of Biophenols Complementary to Olive Leaves

Author:
Japon-Lujan, R., Luque de Castro, M.D.
Source:
Journal of agricultural and food chemistry 2007 v.55 no.11 pp. 4584-4588
ISSN:
0021-8561
Subject:
olives, Olea europaea, chemical constituents of plants, phenolic compounds, oleuropein, verbascoside, taxifolin, plant extracts, branches, extraction, new methods, heat treatment, microwave treatment, continuous systems, high performance liquid chromatography, food processing wastes, plant residues, waste utilization
Abstract:
The extraction of biophenols (BPs) from small branches (fibrous softwood) of olive tree accelerated by microwave assistance is proposed for the first time. Under optimal working conditions, no further extraction of the target analytes was achieved after 10 min, so complete removal of them within this interval was assumed (amounts ca. to 19000, 1000, 2000, 900, and 700 mg/kg of oleuropein, verbascoside, tyrosol, α-taxifolin, and hydroxytyrosol, respectively; the three last BPs are absent in branch-free olive leaves). The extracts required no cleanup or concentration prior to injection into a chromatograph-photodiode array detector assembly for individual separation-quantification. Extraction from this raw material was also implemented in continuous and discontinuous-continuous extractors using ultrasound assistance and superheated liquids, respectively, as auxiliary energies, and the results were compared with those obtained by microwave-assisted extraction. The simultaneous extraction of small branches and leaves from olive tree provided extracts with a higher variety of BPs, but either extracts richer in oleuropein and verbascoside without tyrosol, α-taxifolin, and hydroxytyrosol or rich in these three BPs can be obtained by separate extraction of leaves and branches, respectively.
Agid:
707435