356
Flavanols
Flavanoids are polyphenolic secondary metabolites of plants Kawabata et al. 2015.
Quercetin and kaempferol are the main compounds of this family, being often associated with different sugars, producing glucosides, galactosides, glucuronides, and
diglycosides (Garrido and Borges 2013). The most abundant flavanol is quercetin,
also known as 3,3,4,5,7-pentahydroxyflavone,occurring in a variety of foods such as
onion, apple, broccoli, tea, and red wine (Lakhanpal and Rai 2007). Due to its several pharmacological effects like anti-obesity (Nabavi et al. 2015), antioxidant
(Duenas et al. 2010), anti-inflammatory (Kleemann et al. 2011), and anti-cancer
(Gibellini et al. 2011), current researches are directed towards formulating food
products by adding quercetin. However, under heat treatment, exposure to oxygen
and light, it is susceptible to degradation (Aceituno-Medina et al. 2015).
Quercetin has low aqueous solubility and bioavailability, chemical instability
and short biological half-life, which are main drawbacks of its use in the food and
pharmaceutical applications (Cai et al. 2013). Due to its lipophilic nature, it is moderately soluble in ethanol and highly soluble in dimethyl sulfoxide (Priprem et al.
2008; Ferry et al. 1996). It is therefore difficult to directly incorporate high levels of
quercetin into water-based food matrix. Encapsulation of quercetin may enhance
the physicochemical stability in liquid food products and also the final bioavailability within the human body.
Several studies proved that quercetin can bind with animal proteins, including
human serum albumin (Sengupta and Sengupta 2002), bovine serum albumin (Fang
et al. 2011), collagen (Yang et al. 2009), and β-casein (Mehranfar et al. 2013), which
may enhance its solubility, stability, and bioavailability. Fang et al. (2011) discovered a nanoparticle using bovine serum albumin (BSA) as a matrix to encapsulate
quercetin, and revealed that under both acidic and neutral conditions, BSA nanoparticles could improve the bioactive properties of quercetin for a long period. In
another study, patel and co-workers discovered quercetin-loaded zein nanoparticles
with the average particle size <200 nm and they reported that under the alkaline
condition and exposition to UV-light irradiation, chemical stability of quercetin was
improved entrapped in the colloidal particles (Patel et al. 2012).
Curcumin
Curcumin, also known as 1,7-bis (4-hydroxy-3-methoxyphenyl)-1,6-heptadiene- 3,5dione, is a natural phenolic compound found in the rhizome of the perennial herb,
Curcuma longa (Sharma et al. 2005). Curcuma longa belonging to the group of
curcuminoids, have four main types which are curcumin (77%), demethoxycurcumin (17%), bisdemethoxycurcumin (3%), and cyclocurcumin (Heger et al. 2014).
Curcumin has been traditionally used as a natural food colorant owing to its yelloworange color (Gomez-Estaca et al. 2015). In the last few decades, curcumin has
acquired a good interest due to its potential health-benefitting properties, likeantioxidant, antimicrobial, anticancer, anti-inflammatory, anti-diabetic and wound
F. Jhan et al.
Flavanols
Flavanoids are polyphenolic secondary metabolites of plants Kawabata et al. 2015.
Quercetin and kaempferol are the main compounds of this family, being often associated with different sugars, producing glucosides, galactosides, glucuronides, and
diglycosides (Garrido and Borges 2013). The most abundant flavanol is quercetin,
also known as 3,3,4,5,7-pentahydroxyflavone,occurring in a variety of foods such as
onion, apple, broccoli, tea, and red wine (Lakhanpal and Rai 2007). Due to its several pharmacological effects like anti-obesity (Nabavi et al. 2015), antioxidant
(Duenas et al. 2010), anti-inflammatory (Kleemann et al. 2011), and anti-cancer
(Gibellini et al. 2011), current researches are directed towards formulating food
products by adding quercetin. However, under heat treatment, exposure to oxygen
and light, it is susceptible to degradation (Aceituno-Medina et al. 2015).
Quercetin has low aqueous solubility and bioavailability, chemical instability
and short biological half-life, which are main drawbacks of its use in the food and
pharmaceutical applications (Cai et al. 2013). Due to its lipophilic nature, it is moderately soluble in ethanol and highly soluble in dimethyl sulfoxide (Priprem et al.
2008; Ferry et al. 1996). It is therefore difficult to directly incorporate high levels of
quercetin into water-based food matrix. Encapsulation of quercetin may enhance
the physicochemical stability in liquid food products and also the final bioavailability within the human body.
Several studies proved that quercetin can bind with animal proteins, including
human serum albumin (Sengupta and Sengupta 2002), bovine serum albumin (Fang
et al. 2011), collagen (Yang et al. 2009), and β-casein (Mehranfar et al. 2013), which
may enhance its solubility, stability, and bioavailability. Fang et al. (2011) discovered a nanoparticle using bovine serum albumin (BSA) as a matrix to encapsulate
quercetin, and revealed that under both acidic and neutral conditions, BSA nanoparticles could improve the bioactive properties of quercetin for a long period. In
another study, patel and co-workers discovered quercetin-loaded zein nanoparticles
with the average particle size <200 nm and they reported that under the alkaline
condition and exposition to UV-light irradiation, chemical stability of quercetin was
improved entrapped in the colloidal particles (Patel et al. 2012).
Curcumin
Curcumin, also known as 1,7-bis (4-hydroxy-3-methoxyphenyl)-1,6-heptadiene- 3,5dione, is a natural phenolic compound found in the rhizome of the perennial herb,
Curcuma longa (Sharma et al. 2005). Curcuma longa belonging to the group of
curcuminoids, have four main types which are curcumin (77%), demethoxycurcumin (17%), bisdemethoxycurcumin (3%), and cyclocurcumin (Heger et al. 2014).
Curcumin has been traditionally used as a natural food colorant owing to its yelloworange color (Gomez-Estaca et al. 2015). In the last few decades, curcumin has
acquired a good interest due to its potential health-benefitting properties, likeantioxidant, antimicrobial, anticancer, anti-inflammatory, anti-diabetic and wound
F. Jhan et al.