10
1 Polyphenols and the Mediterranean Diet …
caused by light, pathogen’s infection, parasites, high and low temperature, pollution, etc. Moreover, Bavaresco and coworkers demonstrate that the synthesis of stilbenes (trans- and cis-resveratrols (3,5,4 -trihydroxystilbene), trans- and cis-piceids
(3-O-D-glucosides of resveratrol), trans- and cis-astringins (3-O-D-glucosides of
3-hydroxyresveratrol), trans-and cis-resveratrolosides (4 -O-D-glucosides of resveratrol) and pterostilbene (a dimethylated derivative of stilbene) is stimulated by fungal
infection (ascribed to Botris cinerea) (Bavaresco et al. 1997).
Crozier and coworkers have studied the endogenous flavonoids occurred in some
market gardening (i.e. tomatoes, onions, lettuce and celery). They found that white
onion contains more quercetin than red one: 332 versus 201 µg/kg of fresh weight
(Crozier et al. 1997). The same authors confirmed quercetin of lettuce to be cultivardependent. Round’ lettuce var. Cortina contain low levels (11 µg/kg), while Green
Salad Bowl and ‘Lollo Bionda’ var. Cerieo contain, respectively, 147 and 94 µg/kg.
Remarkably ‘Lollo Rosso’ var. Malibu (R) exhibited highest contents of quercetin
in outer leaves (911 µg/kg) than in inner leaves (450 µg/kg). Similarly to onion and
lettuce, tomato contains a considerable amount of quercetin. The rate of quercetin
may vary, for instance, from 203 µg/kg (in Spanish cherry tomatoes var. Paloma)
to 2.0 µg/kg (Spanish var. Daniella). Similarly, luteolin and apigenin are distributed
differently in celery varieties (Crozier et al. 1997). Luteolin ranged from 6.6 to
40.0 µg/kg in the studied celery varieties, and some of them with no traces of luteolin.
Apigenin ranged from 191 µg/g inside green celery hearts var. Victoria to absence
inside white celery stalks var. Ista.
The data obtained with studied market gardening indicate large varietal differences
in the levels of endogenous phenolic compounds and differences where registered
even between the different parts or tissues in the same plant (Crozier et al. 1997).
1.3.5 Phenols and Fruit’s Ripening Scale
The appropriate time of harvest is one of the most important factors affecting the
nutritional and sensorial quality of fruits; thus, such fact was approached by many
authors from different fields and studied in deep from different angles. In fact, maturation process of fruits consists in a series of biochemical reactions leading to major
modifications. The phenolic fraction changes along maturation, with some phenolic
compounds disappearing while others are formed (Amiot et al. 1986).
Ryan and colleagues have quantified some phenolic compounds in olive cultivars at different maturation stages (Ryan et al. 1999). They found that oleuropein content of Cucco fruits was about 22 mg/g and then decreased with maturation when the colour of olive fruits of this cv turned from green to purple, until
finally disappearing, when the olive fruit turned black (full ripeness).
5 However, the
decrease of oleuropein content corresponded to an increase in total polyphenols.
5 This is a rare case, and the vast majority of olives have contents of oleuropein and derivatives
that impair their consumption as a raw fruit; in olive oil, they are present in minor amounts and
1 Polyphenols and the Mediterranean Diet …
caused by light, pathogen’s infection, parasites, high and low temperature, pollution, etc. Moreover, Bavaresco and coworkers demonstrate that the synthesis of stilbenes (trans- and cis-resveratrols (3,5,4 -trihydroxystilbene), trans- and cis-piceids
(3-O-D-glucosides of resveratrol), trans- and cis-astringins (3-O-D-glucosides of
3-hydroxyresveratrol), trans-and cis-resveratrolosides (4 -O-D-glucosides of resveratrol) and pterostilbene (a dimethylated derivative of stilbene) is stimulated by fungal
infection (ascribed to Botris cinerea) (Bavaresco et al. 1997).
Crozier and coworkers have studied the endogenous flavonoids occurred in some
market gardening (i.e. tomatoes, onions, lettuce and celery). They found that white
onion contains more quercetin than red one: 332 versus 201 µg/kg of fresh weight
(Crozier et al. 1997). The same authors confirmed quercetin of lettuce to be cultivardependent. Round’ lettuce var. Cortina contain low levels (11 µg/kg), while Green
Salad Bowl and ‘Lollo Bionda’ var. Cerieo contain, respectively, 147 and 94 µg/kg.
Remarkably ‘Lollo Rosso’ var. Malibu (R) exhibited highest contents of quercetin
in outer leaves (911 µg/kg) than in inner leaves (450 µg/kg). Similarly to onion and
lettuce, tomato contains a considerable amount of quercetin. The rate of quercetin
may vary, for instance, from 203 µg/kg (in Spanish cherry tomatoes var. Paloma)
to 2.0 µg/kg (Spanish var. Daniella). Similarly, luteolin and apigenin are distributed
differently in celery varieties (Crozier et al. 1997). Luteolin ranged from 6.6 to
40.0 µg/kg in the studied celery varieties, and some of them with no traces of luteolin.
Apigenin ranged from 191 µg/g inside green celery hearts var. Victoria to absence
inside white celery stalks var. Ista.
The data obtained with studied market gardening indicate large varietal differences
in the levels of endogenous phenolic compounds and differences where registered
even between the different parts or tissues in the same plant (Crozier et al. 1997).
1.3.5 Phenols and Fruit’s Ripening Scale
The appropriate time of harvest is one of the most important factors affecting the
nutritional and sensorial quality of fruits; thus, such fact was approached by many
authors from different fields and studied in deep from different angles. In fact, maturation process of fruits consists in a series of biochemical reactions leading to major
modifications. The phenolic fraction changes along maturation, with some phenolic
compounds disappearing while others are formed (Amiot et al. 1986).
Ryan and colleagues have quantified some phenolic compounds in olive cultivars at different maturation stages (Ryan et al. 1999). They found that oleuropein content of Cucco fruits was about 22 mg/g and then decreased with maturation when the colour of olive fruits of this cv turned from green to purple, until
finally disappearing, when the olive fruit turned black (full ripeness).
5 However, the
decrease of oleuropein content corresponded to an increase in total polyphenols.
5 This is a rare case, and the vast majority of olives have contents of oleuropein and derivatives
that impair their consumption as a raw fruit; in olive oil, they are present in minor amounts and