2.1 Polyphenols and Their Relationship to Med Diet Health Benefits
25
(1) Prepared from the sound fruits of varieties of the cultivated olive tree (Olea
europaea L.) that are chosen for their production of olives whose volume, shape,
flesh-to-stone ratio, fine flesh, taste, firmness and ease of detachment from the
stone make them particularly suitable for processing;
(2) Treated to remove its bitterness and preserved by natural fermentation, or by
heat treatment, with or without the addition of preservatives;
(3) Packed with or without covering liquid’.
Many processes have been developed to make harvested table olive edible (IOC
2004; Ozdemir et al. 2014). The edibility of table olives is correlated to the degree
of bitter-tasting secoiridoid glycosides. Oleuropein has been implicated on many
beneficial effects on human health (Barbaro et al. 2014; Omar 2010; Rigacci and
Stefani 2016). Bitterness is considered as a descriptive gustatory attribute of table
olives by IOC (2011). In fact, the IOC adopted, on November 2011, the revised
version of the method (COI/OT/MO No 1/Rev. 2) which establishes criteria and
procedures for the sensory analysis of taste, odour and texture of the table olives,
setting out the systematic for their commercial classification.
Bitterness is also associated with some herbs and spices, which are mainly used
to enhance the flavour of dishes.
Bitterness and astringency are closely connected by quantitative and qualitative
polyphenolic profiles of foods. According to Drewnowski and Gomez-Carneros, the
following list of compounds from plant foods can be noted for their peculiar bitter
taste and astringency (Drewnowski and Gomez-Carneros 2000):
(a) Flavanones sub-class. Naringin is a typical compound responsible for the bitter
taste of grapefruits and citric fruits (i.e. fruit peel and juice).
(b) Flavones sub-class. It includes tangeretin (orange fruit and orange juice) and
nobiletin. Moreover, sinensetin is responsible for the bitter taste of orange fruits,
orange juice and orange concentrates.
(c) Flavonols sub-category. It comprehends quercetin. Quercetin is able to confer
the bitter taste to grapefruit juice, lemon juice, endive, fresh hops, wine, black,
green and oolong tea infusions.
(d) Flavans sub-class. Thanks to catechin and epicatechin, epicatechin gallate (bitter
and astringent), epigallocatechin and epigallocatechin gallate (bitter with sweet
aftertaste), the bitter taste of red wines, tea infusions, and cocoa powder (instant
and low-fat types) can be explained.
(e) Sub-category of phenolic flavonoids. Catechin mono- and polymers—with
molecular weight (MW) < 500 Da—confer the bitter taste for red and rosè
wines, while catechin polymers with MW > 500 (tannins) give astringency to
red wines.
(f) Isoflavones sub-class. Good examples are mainly genistein and daidzein,
responsible for the bitter and the astringency taste of soybeans.
(g) Sub-category of limonoid aglycones. Limonin and nomilin are phenols that may
confer bitterness to grapefruits.
(h) Finally, organosulfur compounds are responsible for the bitter taste of cabbage,
brussels sprouts, cauliflower, turnip (or swede, broccoli, collards, kale, mustard
25
(1) Prepared from the sound fruits of varieties of the cultivated olive tree (Olea
europaea L.) that are chosen for their production of olives whose volume, shape,
flesh-to-stone ratio, fine flesh, taste, firmness and ease of detachment from the
stone make them particularly suitable for processing;
(2) Treated to remove its bitterness and preserved by natural fermentation, or by
heat treatment, with or without the addition of preservatives;
(3) Packed with or without covering liquid’.
Many processes have been developed to make harvested table olive edible (IOC
2004; Ozdemir et al. 2014). The edibility of table olives is correlated to the degree
of bitter-tasting secoiridoid glycosides. Oleuropein has been implicated on many
beneficial effects on human health (Barbaro et al. 2014; Omar 2010; Rigacci and
Stefani 2016). Bitterness is considered as a descriptive gustatory attribute of table
olives by IOC (2011). In fact, the IOC adopted, on November 2011, the revised
version of the method (COI/OT/MO No 1/Rev. 2) which establishes criteria and
procedures for the sensory analysis of taste, odour and texture of the table olives,
setting out the systematic for their commercial classification.
Bitterness is also associated with some herbs and spices, which are mainly used
to enhance the flavour of dishes.
Bitterness and astringency are closely connected by quantitative and qualitative
polyphenolic profiles of foods. According to Drewnowski and Gomez-Carneros, the
following list of compounds from plant foods can be noted for their peculiar bitter
taste and astringency (Drewnowski and Gomez-Carneros 2000):
(a) Flavanones sub-class. Naringin is a typical compound responsible for the bitter
taste of grapefruits and citric fruits (i.e. fruit peel and juice).
(b) Flavones sub-class. It includes tangeretin (orange fruit and orange juice) and
nobiletin. Moreover, sinensetin is responsible for the bitter taste of orange fruits,
orange juice and orange concentrates.
(c) Flavonols sub-category. It comprehends quercetin. Quercetin is able to confer
the bitter taste to grapefruit juice, lemon juice, endive, fresh hops, wine, black,
green and oolong tea infusions.
(d) Flavans sub-class. Thanks to catechin and epicatechin, epicatechin gallate (bitter
and astringent), epigallocatechin and epigallocatechin gallate (bitter with sweet
aftertaste), the bitter taste of red wines, tea infusions, and cocoa powder (instant
and low-fat types) can be explained.
(e) Sub-category of phenolic flavonoids. Catechin mono- and polymers—with
molecular weight (MW) < 500 Da—confer the bitter taste for red and rosè
wines, while catechin polymers with MW > 500 (tannins) give astringency to
red wines.
(f) Isoflavones sub-class. Good examples are mainly genistein and daidzein,
responsible for the bitter and the astringency taste of soybeans.
(g) Sub-category of limonoid aglycones. Limonin and nomilin are phenols that may
confer bitterness to grapefruits.
(h) Finally, organosulfur compounds are responsible for the bitter taste of cabbage,
brussels sprouts, cauliflower, turnip (or swede, broccoli, collards, kale, mustard