Page 330 - Natural Antioxidants, Applications in Foods of Animal Origin

Antioxidant Dietary Fiber: An Approach to Develop Healthy 309
VetBooks.ir dehydrated, and ground apple skin powder contained ~41% TDF and

oxygen radical absorption capacity (ORAC) of 52 mg Trolox equivalents/g
dry weight (Rupasinghe et al., 2008).

8.5.1.3 MANGO PEEL

Mango (Mangifera indica L. Anacardiaceae) is one of the most important
tropical fruits. It is a seasonal fruit thus processed into various popular
products such as puree, nectar, leather, pickles, canned slices, and so forth
(Loelillet, 1994). Processing of mango mainly for pulp and amchur powder,
peel is a by-product which is not utilized for any commercial purpose and
discarded as a waste. This waste should be treated as a specialized residue
due to high levels of residual phenolics as well as DF (Larrauri et al., 1996a).
Peel constitutes about 20% of the whole fruit and its disposal has become a
great problem. According to Ajila et al. (2007) the polyphenol contents in
these peels ranged from 55 to 110 mg/g dry peel. DF content ranged from
45 to 78 % of peel and was found at a higher level in ripe peels. Similarly,
carotenoid content was higher in ripe fruit peels. Vitamins C and E contents
ranged from 188 to 392 and 205 to 509 µg/gm dry peels, respectively, and
these were also found at a higher level in ripe peels. The study conducted by
Ajila et al. (2008) indicated that mango peel contained 51.2% of TDF, 96 mg
GAE/g of polyphenols, and 3092 mg/g of carotenoids.

8.5.1.4 CITRUS BY-PRODUCTS

The amount of residue obtained from the citrus fruits after juice and essen-
tial oil extraction accounts for 50% of the original whole fruit mass (Cohn &
Cohn, 1997). They consist of peels (albedo and flavedo), which are almost
one-fourth of the whole fruit mass, seeds, and fruit pulp (Braddock, 1999).
Citrus peel has been reported to be a good source of pectin and DF in general,
with an equilibrated proportion of soluble and insoluble fractions (Baker,
1994; Larrauri et al., 1994). Approaches to the development of products with
increased dietary benefits from citrus peel have placed emphasis not only
on the recovery of carbohydrates and pectin (Baker, 1994) but also on the
production of potentially important secondary metabolites, such as polyphe-
nols (Manthey & Grohmann, 1996). These fiber-associated polyphenols are
known to exert important health promoting effects (Middleton & Kadas-
wami, 1994). Thus, citrus fruit by-products could be interesting not only for