3.1 Nutritional Importance of Polyphenols
39
irregular orography, water constraints and climate has been favoured plant adaptation to harsh pedoclimatic conditions resulting in an enormous agro-biodiversity,
translated in a large number of autochthone fruits, and a wide range of regional varieties, each one produced in a different time of the year. Taking Italy as example, this
can be illustrated by the 127 entries in the EC DOOR database for geographically
indications, in the category of fruits and vegetables.
5 Identical situation occurs for
other Mediterranean countries, not mention the large number of cultivars that are
still unnoticed.
All of us know the adage ‘an apple a day keeps the doctor away’, yet, to what
extent is this statement true?
In fact, besides their richness in vitamin C, apple is also a rich source of polyphenols, which content ranges from 66 to 430 mg/100 g, according to data from PhenolExplorer database version 3.6.
6 However, the concentrations and types of polyphenols are dependent on the cultivar, as well as on many other factors, such as climate
and agricultural practices (Delgado et al. 2017a, b). The prominent phenolic compounds in apple are phloridzin (it may exist in the glycosylated form, phloretin 2
-Oglucoside). Phloridzin is a dihydrochalcone (Gosch et al. 2010) notably concentrated
in the apple’s skin. Phloridzin and other apple phenolics have been associated with
several health benefits. In detail, phloridzin is active against glycation.
Many studies have demonstrated that apple polyphenols lower blood glucose and
prevent glycation damage (Cermak et al. 2004; Manzano and Williamson 2010).
Apple polyphenols have also been related to longevity (Peng et al. 2011) and may
contribute to the prevention of colorectal cancer: the risk to develop a colorectal
cancer may be inversely correlated with dosage, as one or more apple a day was able
to reduce the risk by 50% (Jedrychowski et al. 2010).
Phenols from apples may also help prevent the development of food allergies.
Procyanidins, which are polymers of catechins, are able to antagonize histamine
released from mast cells involved in the IgE-mediated allergic reaction (Tokura et al.
2005). Mitigation effects against persistent allergic rhinitis have also been reported
(Enomoto et al. 2006).
In addition, phenols from apples may boost immunity: these phytonutrients mitigate the toxicity of staphylococcal α-toxin (Choi et al. 2007). Polyphenols are thought
to bind with toxins produced by the bacterial pathogen, inactivating them and preventing their deleterious effects. Other studies highlighted the antimicrobial action of
apple polyphenols against Pseudomonas sp. and Bacillus sp. and against the so-called
atypical tuberculosis infections (Fattouch et al. 2008; Wong et al. 2008).
5 For further information, please consult the following web page: https://ec.europa.eu/agriculture/
quality/door/list.html?&recordStart=0&filter.dossierNumber=&filter.comboName=&filterMin.
milestone__mask=&filterMin.milestone=&filterMax.milestone__mask=&filterMax.milestone=&
filter.country=IT&filter.category=PDOPGI_CLASS_16&filter.type=&filter.status=
6 For further information: http://phenol-explorer.eu/.
39
irregular orography, water constraints and climate has been favoured plant adaptation to harsh pedoclimatic conditions resulting in an enormous agro-biodiversity,
translated in a large number of autochthone fruits, and a wide range of regional varieties, each one produced in a different time of the year. Taking Italy as example, this
can be illustrated by the 127 entries in the EC DOOR database for geographically
indications, in the category of fruits and vegetables.
5 Identical situation occurs for
other Mediterranean countries, not mention the large number of cultivars that are
still unnoticed.
All of us know the adage ‘an apple a day keeps the doctor away’, yet, to what
extent is this statement true?
In fact, besides their richness in vitamin C, apple is also a rich source of polyphenols, which content ranges from 66 to 430 mg/100 g, according to data from PhenolExplorer database version 3.6.
6 However, the concentrations and types of polyphenols are dependent on the cultivar, as well as on many other factors, such as climate
and agricultural practices (Delgado et al. 2017a, b). The prominent phenolic compounds in apple are phloridzin (it may exist in the glycosylated form, phloretin 2
-Oglucoside). Phloridzin is a dihydrochalcone (Gosch et al. 2010) notably concentrated
in the apple’s skin. Phloridzin and other apple phenolics have been associated with
several health benefits. In detail, phloridzin is active against glycation.
Many studies have demonstrated that apple polyphenols lower blood glucose and
prevent glycation damage (Cermak et al. 2004; Manzano and Williamson 2010).
Apple polyphenols have also been related to longevity (Peng et al. 2011) and may
contribute to the prevention of colorectal cancer: the risk to develop a colorectal
cancer may be inversely correlated with dosage, as one or more apple a day was able
to reduce the risk by 50% (Jedrychowski et al. 2010).
Phenols from apples may also help prevent the development of food allergies.
Procyanidins, which are polymers of catechins, are able to antagonize histamine
released from mast cells involved in the IgE-mediated allergic reaction (Tokura et al.
2005). Mitigation effects against persistent allergic rhinitis have also been reported
(Enomoto et al. 2006).
In addition, phenols from apples may boost immunity: these phytonutrients mitigate the toxicity of staphylococcal α-toxin (Choi et al. 2007). Polyphenols are thought
to bind with toxins produced by the bacterial pathogen, inactivating them and preventing their deleterious effects. Other studies highlighted the antimicrobial action of
apple polyphenols against Pseudomonas sp. and Bacillus sp. and against the so-called
atypical tuberculosis infections (Fattouch et al. 2008; Wong et al. 2008).
5 For further information, please consult the following web page: https://ec.europa.eu/agriculture/
quality/door/list.html?&recordStart=0&filter.dossierNumber=&filter.comboName=&filterMin.
milestone__mask=&filterMin.milestone=&filterMax.milestone__mask=&filterMax.milestone=&
filter.country=IT&filter.category=PDOPGI_CLASS_16&filter.type=&filter.status=
6 For further information: http://phenol-explorer.eu/.