the feed and food industries as additives, supplements, colorants, and in cosmetic and pharmaceutical industries for
nutraceuticals purposes (Jaswir et al. 2011).
A broad array of FVWs such as pea pod powder, fruit
pulp, taro leaves, grape waste, okra, soya, and green gram
waste are computed as prospective sources of mineral, carbon, and nitrogen to produce microbial pigments (Panesar
et al. 2015). Microbial pigments are produced from bacteria,
yeasts, mold, and algae by fermentation processes
(solid-state or submerged fermentation). However, the
amount of exploitation of countless nutrients and production
of pigment may vary depending on the fermentation process
and organism used. This kind of pigments has functions in
the dairy, textile, food, and pharmaceutical industries
(Panesar et al. 2015). Some pigments have abilities to fight
against protozoal, bacteria, fungi, and are inflammatory and
cytotoxic. The pigments play a vital role in upholding optical
health and melanins are incorporated in sunscreen creams to
guard the skin from ultraviolet radiation (Soliev et al. 2011).
Microorganisms like Serratia marcescens, Penicillium purpurogneum, Monascus sp. produce red pigment; Rhodotorula rubra, Monascus sp., Bacillus subtilis, Fusarium
sp. produce yellow pigment; Saccharomyces neoformans,
Cryptococcus sp. are black pigment producers, and so on
(Panesar et al. 2015).
4.3 Flavoring Agent and Aromas
FVWs can also act as the source for the production of
flavoring agents and aroma. Many natural flavoring agents
are volatile compounds manufactured from litters using
biological transformations. The demand for natural and
familiar flavors like vanillin, strawberry flavor, pineapple
flavor, etc., are increasing. Vanillin formed from vanillic
acid gives vanilla flavor. This vanilla is extracted from
Vanilla planifolia by microbial transformation, fermentation,
and enzymatic reactions. The precursor of vanilla is ferulic
acid that is present in pineapple peel, orange peel, pomegranate peel. Vanilla flavor is the leading flavor and vastly
used in detergent, food, beverages, pharmaceutical, and
cosmetic industries (Tilay et al. 2008; Sagar et al. 2018; Lun
et al. 2014).
Furaneol is a critical flavor/aroma compound, developing
a flavor of caramelized pineapple in fruits such as pineapples, strawberries, mangoes, raspberries, etc. It imparts fruity
and strawberry flavor at low concentration, whereas at high
concentration it gives caramel and burnt sugar flavor. Methyl
ether is responsible for aroma (Pickenhagen et al. 1981).
Essential volatile oils can be obtained from FVWs like
orange peels, citrus peel, lemon peels, fruit seeds, garlic
residues, thyme remains, oregano waste, clove residues,
basil remainders, cinnamon rests, coriander leftover, ginger
coverings, rosemary residues, and peppermint remains. The
numerous volatile compounds are existent in the essential oil
that retain flavoring and antimicrobial properties (Kalemba
and Kunicka 2003). The utmost volatile compounds are
alcohols, organic sulfur compounds, terpenoids, and aldehydes (Berger 2007). These essential oils are added in producing fragrances, bath products, cosmetics, household
cleaning products, and flavoring of drink and food (Berger
2007). For instance; essential oils extracted from oranges
have medicinal values, so they are supplemented as a constituent in gastric, purgative, and flatus-relieving preparations and tea formulations. Additionally, orange oil is
applicable in remedying piles, slipping or falling of rectum
and uterus, and diarrhea. D-limonene present in lemon
improves immunity, pledges irregular moods, stimulates,
boosts and activates mind and body, and cares skin by
reducing wrinkles (Wadhwa et al. 2013; Berger 2007).
4.4 Dietary Fiber
Nowadays, people are being more health concerned for a
healthy lifestyle and are more interested in having fruits rich
in minerals, bioactive compounds, dietary fibers, and low in
calories, sodium, and fats in their food. Dietary fibers are the
indigestible carbohydrates present in plant cell walls and
show central responsibilities in human diet together with
health (Palafox-Carlos et al. 2011). Plant carbohydrate
polymers and other non-carbohydrate components like pectin, hemicellulose, hemicellulose, waxes, polyphenols,
resistant protein are dietary fiber (Elleuch et al. 2011). FVWs
and agro-industrial by-products are high in fibers thus used
as food supplements (Kowalska et al. 2017). Intake of
dietary fiber reduces obesity, diabetes, cardiovascular diseases, hyperlipidemia, hypercholesterolemia, and hyperglycemia (Mann and Cummings 2009). Dietary fiber helps
in the absorption of antioxidants like carotenoids and phenolic compounds. Dietary fiber also regulates digestion,
absorption, and metabolism of nutrients. In addition, dietary
fiber increases the fecal bulk, excites colonic fermentation,
lowers insulin and cholesterol levels. Dietary fiber serves as
food additives and delivers commercial profits to the pharmaceutical, food, and cosmetic industries (Elleuch et al.
2011; Kowalska et al. 2017). Dietary fiber has good water
and oil holding capacity, emulsifying or/and gel-forming
capacity, and swelling capacity so that it helps in lowering
cholesterol, modifying the viscosity of intestinal contents,
and forming gel with bile in the intestine (Palafox-Carlos
et al. 2011; Elleuch et al. 2011; Ayala-Zavala et al. 2011).
The addition of dietary fibers aid to modify the stickiness,
consistency, self-life, and sensual characters of the foodstuffs
like bakery products, dairy, meats, jams, soups, etc. However, the addition of fiber must be in the appropriate
154
S. Shrestha et al.
nutraceuticals purposes (Jaswir et al. 2011).
A broad array of FVWs such as pea pod powder, fruit
pulp, taro leaves, grape waste, okra, soya, and green gram
waste are computed as prospective sources of mineral, carbon, and nitrogen to produce microbial pigments (Panesar
et al. 2015). Microbial pigments are produced from bacteria,
yeasts, mold, and algae by fermentation processes
(solid-state or submerged fermentation). However, the
amount of exploitation of countless nutrients and production
of pigment may vary depending on the fermentation process
and organism used. This kind of pigments has functions in
the dairy, textile, food, and pharmaceutical industries
(Panesar et al. 2015). Some pigments have abilities to fight
against protozoal, bacteria, fungi, and are inflammatory and
cytotoxic. The pigments play a vital role in upholding optical
health and melanins are incorporated in sunscreen creams to
guard the skin from ultraviolet radiation (Soliev et al. 2011).
Microorganisms like Serratia marcescens, Penicillium purpurogneum, Monascus sp. produce red pigment; Rhodotorula rubra, Monascus sp., Bacillus subtilis, Fusarium
sp. produce yellow pigment; Saccharomyces neoformans,
Cryptococcus sp. are black pigment producers, and so on
(Panesar et al. 2015).
4.3 Flavoring Agent and Aromas
FVWs can also act as the source for the production of
flavoring agents and aroma. Many natural flavoring agents
are volatile compounds manufactured from litters using
biological transformations. The demand for natural and
familiar flavors like vanillin, strawberry flavor, pineapple
flavor, etc., are increasing. Vanillin formed from vanillic
acid gives vanilla flavor. This vanilla is extracted from
Vanilla planifolia by microbial transformation, fermentation,
and enzymatic reactions. The precursor of vanilla is ferulic
acid that is present in pineapple peel, orange peel, pomegranate peel. Vanilla flavor is the leading flavor and vastly
used in detergent, food, beverages, pharmaceutical, and
cosmetic industries (Tilay et al. 2008; Sagar et al. 2018; Lun
et al. 2014).
Furaneol is a critical flavor/aroma compound, developing
a flavor of caramelized pineapple in fruits such as pineapples, strawberries, mangoes, raspberries, etc. It imparts fruity
and strawberry flavor at low concentration, whereas at high
concentration it gives caramel and burnt sugar flavor. Methyl
ether is responsible for aroma (Pickenhagen et al. 1981).
Essential volatile oils can be obtained from FVWs like
orange peels, citrus peel, lemon peels, fruit seeds, garlic
residues, thyme remains, oregano waste, clove residues,
basil remainders, cinnamon rests, coriander leftover, ginger
coverings, rosemary residues, and peppermint remains. The
numerous volatile compounds are existent in the essential oil
that retain flavoring and antimicrobial properties (Kalemba
and Kunicka 2003). The utmost volatile compounds are
alcohols, organic sulfur compounds, terpenoids, and aldehydes (Berger 2007). These essential oils are added in producing fragrances, bath products, cosmetics, household
cleaning products, and flavoring of drink and food (Berger
2007). For instance; essential oils extracted from oranges
have medicinal values, so they are supplemented as a constituent in gastric, purgative, and flatus-relieving preparations and tea formulations. Additionally, orange oil is
applicable in remedying piles, slipping or falling of rectum
and uterus, and diarrhea. D-limonene present in lemon
improves immunity, pledges irregular moods, stimulates,
boosts and activates mind and body, and cares skin by
reducing wrinkles (Wadhwa et al. 2013; Berger 2007).
4.4 Dietary Fiber
Nowadays, people are being more health concerned for a
healthy lifestyle and are more interested in having fruits rich
in minerals, bioactive compounds, dietary fibers, and low in
calories, sodium, and fats in their food. Dietary fibers are the
indigestible carbohydrates present in plant cell walls and
show central responsibilities in human diet together with
health (Palafox-Carlos et al. 2011). Plant carbohydrate
polymers and other non-carbohydrate components like pectin, hemicellulose, hemicellulose, waxes, polyphenols,
resistant protein are dietary fiber (Elleuch et al. 2011). FVWs
and agro-industrial by-products are high in fibers thus used
as food supplements (Kowalska et al. 2017). Intake of
dietary fiber reduces obesity, diabetes, cardiovascular diseases, hyperlipidemia, hypercholesterolemia, and hyperglycemia (Mann and Cummings 2009). Dietary fiber helps
in the absorption of antioxidants like carotenoids and phenolic compounds. Dietary fiber also regulates digestion,
absorption, and metabolism of nutrients. In addition, dietary
fiber increases the fecal bulk, excites colonic fermentation,
lowers insulin and cholesterol levels. Dietary fiber serves as
food additives and delivers commercial profits to the pharmaceutical, food, and cosmetic industries (Elleuch et al.
2011; Kowalska et al. 2017). Dietary fiber has good water
and oil holding capacity, emulsifying or/and gel-forming
capacity, and swelling capacity so that it helps in lowering
cholesterol, modifying the viscosity of intestinal contents,
and forming gel with bile in the intestine (Palafox-Carlos
et al. 2011; Elleuch et al. 2011; Ayala-Zavala et al. 2011).
The addition of dietary fibers aid to modify the stickiness,
consistency, self-life, and sensual characters of the foodstuffs
like bakery products, dairy, meats, jams, soups, etc. However, the addition of fiber must be in the appropriate
154
S. Shrestha et al.