Page 440 - Refining Biomass Residues for Sustainable Energy and Bioproducts

Food industry waste biorefineries: future energy, valuable recovery, and waste treatment 399

polyphenols also remains in the waste after juice production. Catechinscatechins,
hydroxycinnanates, phloretin glycosides, procyanidins, and many other compounds
are majorly isolated from the waste of fruit production (Schieber et al., 2001a;
´
Cetkovi´ c et al., 2008). A number of in vitro model systems have been developed to
check out the antioxidant properties of polyphenols present in apple pomace.
Lu and Foo (2000) utilized β-carotene/linoleic acid system to examine the
2, 2-Diphenyl-1- picrylhydrazyl (DPPH), superoxide ion radical, and antioxidant
properties of polyphenols, such as epicatechin and its dimer, trimer, tetramer, and
chlorogenic acid. The phenolic components and flavonoids of apple extract exhibit
the antiproliferative properties and lead to the inhibition of tumor cell proliferation
like colon cancer in vitro (Veeriah et al., 2006).
Grapes, world’s largest fruit crop, are usually utilized for the production of juice,
jams, and raisins with 80% utilization in wine production (Louli et al., 2004;
Schieber et al., 2001b). The composition of the waste produced during wine produc-
tion considerably depends on the variety of grape and technology utilized.
However, approximately 5 9 million tons of waste produced every year from wine
industry with increased demand of oxygen to degrade sugars, tannins, polyphenols,
pectins, lipids, etc. along with adverse effect on flora and fauna of the surroundings.
All these consequences demand the better ways for the utilization of winery waste
instead of animal feed or fertilizer only. The phenolic compounds of grapes possess
the antioxidative properties as they lead to the inhibition of LDL oxidation.
Therefore grape pomace could be utilized as food ingredients with high amount of
phenolic compounds. Grape seed oil is also a treasure of fatty acid, which contents
mainly linoleic acid (Kamel et al., 1985). A number of high-value products, such as
ethanol, tartrates, citric acid, hydrocolloids, and dietary fibers, have been regained
from grape pomace (Yi et al., 2009; Maier et al., 2009). A large amount of phenolic
compounds could be extracted from the grape pomace via enzymatic treatment
(Iacopini et al., 2008). The yield anthocyanin, the most valuable product of grape
pomace, can be improved by increasing the shelf life of grape pomace via gamma
irradiation (Ayed et al., 1999). Catechin, epicatechin, epicatechin gallate, and epi-
gallocatechin represent the major constituents of the tannins present in grape skin
(Ðilas et al., 2009). The great antioxidant potency of phenolic extracts of grape
seeds enhances their scope of the commercialization as these extracts can be
utilized as to increase the shelf life of food.

17.8 Steroidal alkaloids from potato peel waste

Potato-processing industries generate a wide amount, that is, 70 140 t of potato
peels as by-product during the production of crisps (Chang, 2011). These potato
peels are either used for animal feed or directly discarded in the environment,
where these are highly sensitive to microbial spoilage (Schieber and Saldan ˜a,
2009). Potato peels are a treasure of steroidal alkaloids having toxic properties to
restrict the growth of bacteria, fungi, and also rich source of carbohydrates,