Page 422 - Biosystems Engineering

Phenolic Substances fr om Olives & Olive Mill Pr oducts 399

Few studies have been done on the phenol’s evolution during
storage and cooking of virgin olive oil. During frying, olive antioxi-
dants degrade with different ratios: tocopherols degrade before the
hydroxytyrosol, which degrades before tyrosol (Pellegrini et al. 2001).
In optimal storage conditions, in a dark and cool room, total phenols
and hydroxytyrosol decrease significantly in relationship with the
time (Cinquanta et al. 1997).
Olive polyphenols, especially oleuropein and hydroxytyrosol,
have been intensively studied regarding their effect on human health
and their medicinal potential. Although most studies have been done
in vitro, some statistical studies on human populations confirm the
benefit of olive oil (Hill and Giacosa 1992). Higher virgin olive oil
consumption is associated with a lower incidence of coronary heart
disease and the risk of breast, prostate, and colon cancers (Tuck and
Hayball 2002).
Finally, potential nutraceutical properties of olive polyphenols
are synthesized in Table 14.2.

Cytostatic and cytotoxic activity against Owen et al. 2000; Saenz et al.
tumoral cells 1998
Hypocholesterolaemic effect De Pasquale et al. 1991
Increase resistance of LDLs to oxidation Auroma et al. 1998; Visioli et al.
1995; Visioli et al. 2001; Salami
et al. 1995; Fito et al. 2000
Scavenging peroxy radicals, hydroxy Visioli et al. 1998; Visioli and
radicals and superoxide anions Galli 1999
Hypoglycaemic effect and antidiabetic Trovato et al. 1993
activity
Inhibition of platelet aggregation Petroni et al. 1995
Reduction of formation of proinflammatory De La Puerta et al. 1999;
molecules thromboxane B and leukotriene Martinez-Domingues et al. 2001
2
B by activated human leukocytes
4
Antioxidant effects in cellular and animal Manna et al. 1997; Speroni et al.
models 1998
Prevention of passive smoking oxidative Visioli et al. 2000
stress
Antimicrobial activity against many Juven and Henis 1970; Fleming
pathogenic microorganisms, including et al. 1973; Bisognano et al.
bacteria, fungi, viruses, and parasitics, 1999
and protozoans

TABLE 14.2 Some Potential Nutritional Properties Ascribed to Phenolic
Substances Present in Olives and Related Olive Mill Products