Biophenolic profile in olives by nuclear magnetic resonance

The molecular composition of biophenols in olive fruit was investigated in order to experiment with novel procedures for the determination of these microcomponents in fresh and processed table olives. The presence of biophenols in table olives, with recognized antioxidant activity, can be strictly linked to the texture and the organoleptic characteristics of the food product, giving a functional value to this Mediterranean food. Olives from Spain ("Hojiblanca" cv.), Portugal ("Douro" cv.), Greece ("Conservolia" and "Thasos"cv.) and Italy ("Taggiasca" and "Cassanese" cv.) were examined, because the experimental data, checked by high-performance liquid chromatography (HPLC), show molecular composition differences in the tested samples related to the geographic area of analyzed olive fruit cultivars [Bianco, A., & Uccella, N. (2000). Biophenolic components of olives. Food Research International, 33, 475-485]. Three different protocols were utilized: the first one allows the determination of the biophenolic content present as free and esterified compounds; the second affords the total biophenolic content; the third indicates the biophenols present as glycosides. The biophenolic content, which was previously determined by classic HPLC methods (Bianco & Uccella, 2000), was checked by a simple]H-NMR experiment. The comparison between the data obtained from H-1-NMR with those measured by HPLC, indicates a good agreement and suggests the possibility of employing H-1-NMR for the rapid determination of biophenolic content in olives and also in other foods. (C) 2001 Elsevier Science Ltd. All rights reserved.