358
the encapsulation efficiencies of all three nanoparticles were approximately 90%
(Lestringant et al. 2014).
Proanthocyanidins (PACs)
Proanthocyanidins (PACs) are secondary metabolites of plants, which are oligomers
of (−)-epicatechin and (+)-catechin (Zou et al. 2012). PACs are effective in preventing urinary tract infections (Zou et al. 2012). However, similar to other polyphenols,
they are susceptible to degradation at high temperature, when exposed to oxygen,
and also in the gastrointestinal tract due to the low pH and the presence of other
compounds (Berendsen et al. 2015). Besides, PACs affects sensory attributes as it
imparts bitterness and astringency (Berendsen et al. 2015). Therefore, encapsulation of PACs is of interest. Links et al. (2015) encapsulated sorghum condensed
tannins (SCT) in kafirin matrix by coacervation. The encapsulation efficiency of
SCT was around 48% and only a limited amount of SCT was digested undersimulated gastrointestinal fluid conditions. In another study, gelatin particles was used
for the encapsulation of pomegranate ellagitannins (PPE) containing mainly punicalagin by gelation. The formed particles had a size of below 200 nm and exhibited
a high loading efficiency (Li et al. 2011).
Phenolic Acid Derivatives
Phenolic acid derivatives include derivatives of hydroxylbenzoic acid (HBA) and
hydroxycinnamic acid (HCA). They are rarely present in the free form as they are
oftenbound to sugars by glycosidic linkage (Cote et al. 2010). Like HCA derivatives, HBA derivatives (ellagic, gallic and vanillic acid) are also bound with sugars.
Ellagi-tannins are formed by the esterification of ellagic acid with flavan-3-ols
(Cote et al. 2010). Phenolic acids are correlated to their characteristic flavour as well
as their potent antioxidant and antimicrobial properties (Pappas and Schaich 2009).
In general, HAs have low aqueous solubility and a bitter taste and therefore, in order
to increase its solubility and bioavailability, protect from degradation, and mask
unpleasant tastes, HAs may be encapsulated in polymeric nanoparticles for application in the food industry.
Because of the antioxidant activity of phenolic acids, several studies have been
investigated to study their encapsulation. Gallic acid was encapsulated in zein fibers
by electrospinning. The generated ultra-fine fibers had a diameter ranging from 327
to 387 nm. The antioxidant activity of gallic acid was retained in the fibers (Neo et al.
2013). Besides electrospinning, caffeic acid was encapsulated in an O/W emulsion
at different pH and it was found thatthe antioxidant activity of caffeic acid was
enhanced by the presence of BSA (Almajano et al. 2007). Some natural polyphenols,
F. Jhan et al.
the encapsulation efficiencies of all three nanoparticles were approximately 90%
(Lestringant et al. 2014).
Proanthocyanidins (PACs)
Proanthocyanidins (PACs) are secondary metabolites of plants, which are oligomers
of (−)-epicatechin and (+)-catechin (Zou et al. 2012). PACs are effective in preventing urinary tract infections (Zou et al. 2012). However, similar to other polyphenols,
they are susceptible to degradation at high temperature, when exposed to oxygen,
and also in the gastrointestinal tract due to the low pH and the presence of other
compounds (Berendsen et al. 2015). Besides, PACs affects sensory attributes as it
imparts bitterness and astringency (Berendsen et al. 2015). Therefore, encapsulation of PACs is of interest. Links et al. (2015) encapsulated sorghum condensed
tannins (SCT) in kafirin matrix by coacervation. The encapsulation efficiency of
SCT was around 48% and only a limited amount of SCT was digested undersimulated gastrointestinal fluid conditions. In another study, gelatin particles was used
for the encapsulation of pomegranate ellagitannins (PPE) containing mainly punicalagin by gelation. The formed particles had a size of below 200 nm and exhibited
a high loading efficiency (Li et al. 2011).
Phenolic Acid Derivatives
Phenolic acid derivatives include derivatives of hydroxylbenzoic acid (HBA) and
hydroxycinnamic acid (HCA). They are rarely present in the free form as they are
oftenbound to sugars by glycosidic linkage (Cote et al. 2010). Like HCA derivatives, HBA derivatives (ellagic, gallic and vanillic acid) are also bound with sugars.
Ellagi-tannins are formed by the esterification of ellagic acid with flavan-3-ols
(Cote et al. 2010). Phenolic acids are correlated to their characteristic flavour as well
as their potent antioxidant and antimicrobial properties (Pappas and Schaich 2009).
In general, HAs have low aqueous solubility and a bitter taste and therefore, in order
to increase its solubility and bioavailability, protect from degradation, and mask
unpleasant tastes, HAs may be encapsulated in polymeric nanoparticles for application in the food industry.
Because of the antioxidant activity of phenolic acids, several studies have been
investigated to study their encapsulation. Gallic acid was encapsulated in zein fibers
by electrospinning. The generated ultra-fine fibers had a diameter ranging from 327
to 387 nm. The antioxidant activity of gallic acid was retained in the fibers (Neo et al.
2013). Besides electrospinning, caffeic acid was encapsulated in an O/W emulsion
at different pH and it was found thatthe antioxidant activity of caffeic acid was
enhanced by the presence of BSA (Almajano et al. 2007). Some natural polyphenols,
F. Jhan et al.