1628 J. Agric. Food Chem., Vol. 48, No. 5, 2000
Capozzi et al.
Bianco, A. D.; Piperno, A.; Romeo, G.; Uccella, N. NMR
experiments of oleuropein biomimetic hydrolysis. J . Agric.
Food Chem. 1999a , 47, 3665-3668.
Bianco, A. D.; Muzzalupo, I.; Piperno, A.; Romeo, G.; Uccella,
N. Bioactive derivatives of oleuropein from olive fruits. J .
Agric. Food Chem. 1999b, 47, 3531-3534.
minor protective constituents of olive fruits also control
penetration of the alkaline solution, thus affecting the
hydrolysis of 1, which determines most table olive
treatments and produces the selective formation of 3
versus 4.
The experimentally observed selection process from
1 to 3 and 4 can be interpreted on the basis of the buffer
capacity of the olive flesh. In effect, because the total
organic acid content of the olive mesocarp tends to
increase during growth, the pH also increases slightly,
due to the combined acidity changes of up to 157 mM
(Garrido Fernandez et al., 1997b): these variations
modify the buffering capacity of the table olive pulp,
thus generating the appropriate condition for the selec-
tive reactivity of 1.
During the debittering process, however, the cell wall
molecular structure and composition of fresh fruits are
influenced by enzymatic molecular degradation and
solubilization, for example, by the alkaline treatment
technomimetically performed. Therefore, an important
role in table olive texture and changes during the fruit
processing is revealed by the initial relatively powerful
alkaline procedure, which brings about changes in the
consistency and palatability of the final processed
produce.
Skin permeability, thus related to the epicarp molec-
ular constituents of the selected olive cultivar, could
appear to be the major limit in the debittering process
because the alkaline hydrolysis of BP 1 requires milder
basic conditions than those industrially applied. There-
fore, the concentration of the lye treatment mainly
serves to penetrate the skin through the cutin, affecting
the molecular structure of the wax esters, the morpho-
logical structure of the olive skin, and the overall texture
of the final table olive products.
Thus, an initial treatment with a concentrated lye
would reasonably be followed by a more dilute one or
by a suitable basic solution. The critical biomolecular
structure of the olive skin components deserves atten-
tion in the improvement of the debittering process,
which would allow also for a better texture of the final
product because the high NaOH concentration could
give rise to â-elimination of pectic and cellulase moieties
(J imenez et al., 1997).
Bianco, A. D.; Uccella, N. Biophenolic Components of Olives.
Food Res. Int. 2000, in press.
Bisignano, G.; Tomaino, A.; Lo Cascio, R.; Crisafi, G.; Uccella,
N.; Saija, A. On the In-vitro Antimicrobial Activity of
Oleuropein and Hydroxytyrosol. J . Pharm. Pharmacol.
1999, 51, 971-974.
Borzillo, A.; Iannotta, N.; Uccella, N. Oinotria Table Olives:
Quality Evaluation during Ripening and Processing by
Biomolecular Components. Eur. Food Res. Technol. 2000,
in press.
Brenes, M.; de Castro, A. Transformation of Oleuropein and
its Hydrolysis Products during Spanish-style Green Olive
Processing. J . Sci. Food Agric. 1998, 77, 353-358.
Brenes, M.; Rejano, L.; Garcia, P.; Sanchez, A. H.; Garrido, A.
Biochemical Changes in Phenolic Compounds during Span-
ish Style Green Olive Processing. J . Agric. Food Chem. 1995,
43, 2702-2706.
Brenes-Balbuena, M.; Garcia, P.; Garrido, A. Phenolic com-
pounds related to the black color formed during the process-
ing of ripe olives. J . Agric. Food Chem. 1992, 40, 1192-
1196.
Brighigna, A. Le Olive da Tavola; Edagricole: Bologna, Italy,
1998.
Castelli, F.; Uccella, N.; Trombetta, D.; Saija, A. Differences
between Coumaric and Cinnamic Acids in Membrane Per-
meation as Evidenced by Time-Dependent Calorimetry. J .
Agric. Food Chem. 1999, 47, 991-995.
Casuscelli, F.; De Nino, A.; Gallo, F. R.; Procopio, A.; Romeo,
G.; Uccella, N. Olea europea L. Biophenols; Modern Analyti-
cal Applications. In Ricerche e Innovazioni nell’Industria
Alimentare; Chiriotti Editore: Pinerolo, Italy, 1994; Vol. I.
Connell, J . H. History and scope of the olive industry. In Olive
Production Manual; Ferguson, L., Steven Sibbett, G., Mar-
tin, G. C., Eds.; University of California: Los Angeles, CA,
1994; Publ. 3353, pp 1-10.
Damtoft, S.; Franzyk, H.; J ensen, S. R. Excelsioside, a Seco-
iridoid from Fraxinus excelsior. Phytochemistry 1992, 31,
4197-4201.
Gariboldi, P.; J ommi, G.; Verotta, L. Secoiridoids from Olea
europea. Phytochemistry 1986, 25, 865-869.
Garrido Fernandez, A.; Fernandez Diez, M.; Adams, M. R.
Physicochemical Changes in brines and fruit during Fer-
mentation. Table Olives, Production and Processing; Chap-
man and Hall: London, U.K., 1997a; bp 101.
Goldberg, I. Health attributes of functional foods. In Func-
tional Foods; Chapman and Hall: London, U.K., 1994.
Gutierrez, F.; Albi, M. A.; Palma, R.; Rios, J . J .; Olias, J . M.
Bitter Taste of Virgin Olive Oil: Correlation of Sensory
Evaluation and Instrumental HPLC Analysis. J . Food Sci.
1989, 54, 68-70.
ACKNOWLEDGMENT
We thank Dr. E. Barrese for collaboration and Prof.
A. D. Bianco for helpful discussions.
LITERATURE CITED
Haslam, E. Natural polyphenols (vegetable tannins) as
drugs: possible mode of action. J . Nat. Prod. 1996, 59, 205-
215.
Inouye, H.; Yoshida, T.; Tobita, S.; Tanaka, K.; Nishioka, T.
Uber die Monoterpenglucoside und Verwandte Naturstoffes
XXII. Absolutstrukturen des Oleuropeins, Kingisids und
Morronisids. Tetrahedron 1974, 30, 201-209.
J imenez, A.; Heredia, A.; Guillen, R.; Fernandez-Bolonos, J .
Correlation between Soaking Conditions, Cations Content
of Cell Wall, and Olive Firmness during Spanish Green
Olive Processing. J . Agric. Food Chem. 1997, 45, 1653-
1658.
Kuwajima, H.; Uemura, T.; Takaishi, K.; Inoue, K.; Inouye,
H. A secoiridoid Glucoside from Olea europea. Phytochem-
istry 1988, 27, 1757-1759.
Amiot, M. J .; Fleuriet, A.; Machiex, J . J . Importance and
evolution of phenolic compounds in olive during growth and
maturation. J . Agric. Food Chem. 1986, 34, 823-826.
Amiot. M. J .; Fleuriet, A.; Macheix, J . J . Accumulation of
oleuropein derivatives during olive maturation. Phytochem-
istry 1989, 28, 67-69.
Balatsouras, G. Table olive processing technology. In World
Olive Encyclopaedia; Lucchetti, F., Ed.; IOOC: Madrid,
Spain, 1996.
Bianco, A. D.; Chiacchio, U.; Rescifina, A.; Romeo, G.; Uccella,
N. Biomimetic Supramolecular Biophenol-Carbohydrate and
Biophenol-Protein Models by NMR Experiments. J . Agric.
Food Chem. 1997, 45, 4281-4285.
Bianco, A. D.; Mazzei, R. A.; Melchioni, C.; Romeo, G.; Scarpati,
M. L.; Soriero, A.; Uccella, N. Microcomponents of Olive Oils
III. Glucosides of 2(3,4-dihydroxyphenyl)ethanol. Food Chem.
1998, 63, 461-464.
Limiroli, R.; Consonni, R.; Ottolina, G.; Marsilio, V.; Bianchi,
G.; Zetta, L. 1H NMR characterization of oleuropein agly-
cones. J . Chem. Soc., Perkin Trans. 1 1995, 5, 1519-1523.