Page 327 - Natural Antioxidants, Applications in Foods of Animal Origin

306 Natural Antioxidants: Applications in Foods of Animal Origin
VetBooks.ir Several studies have highlighted the beneficial effects of grape or wine

polyphenols on human health (Ho et al., 1994; Rice-Evans et al., 1997;
Lurton, 2003; Frankel, 1999). More specifically, the antioxidative proper-
ties of many natural polyphenols may exert a chemopreventive role toward
cardiovascular and degenerative diseases (Halpern et al., 1998; Renaud &
De Lorgeril, 1992), including neurodegenerative pathologies (Esposito et
al., 2002) and cancer (Bozidar, 1995). Grape skins are rich in anthocya-
nins, a group of polyphenols well known for their beneficial properties
(Katsube et al., 2003; Wang et al., 1997; Ghiselli et al., 1998; Kong et al.,
2003; Kähkönen & Heinonen, 2003). Pérez-Jiménez et al. (2008) found that
fibers from grapes show higher reducing efficacy in lipid profile and blood
pressure with respect to oat fiber or psyllium due to combined effect of DF
and antioxidants. Wine grape pomace as ADF not only retarded human low-
density lipoprotein oxidation in vitro (Meyer et al., 1998) but also helped
to enhance the gastrointestinal health of the host by promoting a beneficial
microbiota profile (Pozuelo et al., 2012).
The general composition of two by-products of the Manto Negro red
grape (Vitis vinifera) variety, namely pomace and stem, were determined
(Llobera & Cañellas, 2007). Both by-products had high contents of TDF,
comprising three fourths of the total dry matter. Notable were the high
percentage of soluble fiber (15%) in relation to the TDF for the pomace, as
well as the high content of Klason lignin (KL) in both by-products, espe-
cially in the stem (31.6%). The free radical scavenging capacity (EC ) of
50
the by-products was found as 0.46 mg DM/mg DPPH (stem) and 1.41 mg
DM/mg DPPH (pomace). Thus both by-products of the vinification process,
particularly the stem, present excellent antioxidant properties as free radical-
scavengers. The methanolic extracts (MeOH) obtained from de-stemmed
grape pomace samples of five Sicilian red grape cultivars were evaluated for
their DPPH and ABTS radical scavenging capacity (Ruberto et al., 2007).
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All the MeOH extracts showed significant antioxidant activity, with some
differences between the two methods employed. There was large variability
in the total anthocyanin (TA) and flavonol (TF) contents of the extracts,
as well as in the quantitative distribution of the single anthocyanins and
flavonols.
Grape skins, comprising on average, 82% of the wet weight of wine grape
pomace (Jiang et al., 2011), contain multiple types of polyphenols, including
39 types of anthocyanins, HCA, catechins, and flavonols (Kammerer et
al., 2004). The skins of two white wine grape pomace (WWGP) and three
red wine grape pomace (RWGP) were analyzed for their DF and phenolic
composition (Deng et al., 2011). IDF represented 95.5% of TDF, composed