example, agro-industrial wastes can be reused for bioenergy
generation, for composting, or in specific cases, for animal
feed. However, these agro-industrial wastes have been
characterised by containing nutrients (vitamins, minerals,
trace elements), dietary fibres, enzymes, oils, and bioactive
compounds (phenolic compounds, carotenoids, glucosinolates, and flavonoids) (Sagar et al. 2018; Saini et al. 2019).
The interest in bioactive compounds has increased in recent
decades due to their great abundance in the plant kingdom as
well as their multiple beneficial properties to prevent and be
beneficial against a large number of pathologies such as
cancer, cardiovascular, neurodegenerative diseases, and
inflammation (Altemimi et al. 2017; Fernández-Ochoa et al.
2020).
Since large amounts of agri-food are considered
non-edible food or waste because they do not complete the
established standards for their commercialisation, large
quantities of food by-products are generated throughout the
supply chain from the initial steps to the final consumption
stages (Torres-Valenzuela et al. 2020). In this scenario, the
presence of bioactive compounds makes it possible to use
them for the development of high added value products such
as functional foods, nutraceuticals, cosmeceuticals, or
applications in the textile or pharmaceutical industries. To
isolate these phytochemical compounds, a sophisticated step
of extraction has to be carried out to use them later in the
potential applications related to high added value products
(Kumar et al. 2017). For this objective, different extraction
strategies have been optimised to do this process more
sustainable, such as ultrasound-assisted extraction (UAE),
subcritical water extraction (SWE), microwave-assisted
extraction (MAE), supercritical fluid extraction (SFE), or
enzyme-assisted extraction (EAE) (Marić et al. 2018).
The possibility of reusing agro-industrial wastes for the
elaboration of high added value products reduces the environmental impact but also represents an attractive proposal
for companies that can generate new alternative ways of
business opportunities. These types of strategies, defined as
a circular economy, have been related to the sustainable
development goals and are increasingly being implemented
by companies in recent years (Sauvé et al. 2016;
Rodriguez-Anton et al. 2019).
In this chapter, the potential applications of high added
value products obtaining from the reuse of agro-industrial
waste and the role that these applications can have in the
bioeconomy of companies and in strategies against climate
change are presented. In addition, the main agro-industrial
wastes from vegetables, fruits, or cereals are described, as
well as the main phytochemical compounds present in them
and the green extraction techniques to isolate these
phytochemicals.
2 The Role of Agro-Industrial Wastes
in Bioeconomy
Globally, large amounts of agro-industrial wastes and
by-products, which can be ‘on/off farm’ contribute to environmental stress. However, sustainable development has to
do with a movement of building on ‘circular economy’ or
‘bioeconomy’ by high value-added products based on
agro-industrial waste recycling. Moreover, it could align
with the achievement of carbon neutrality and the obtainment of the UN Sustainable Development Goals
(El-Chichakli et al. 2016).
Regarding the terms, there are different concerns about
Green, Circular, and Bio-economy, but despite the differences, they have common economic, environmental, and
social aims (D’Amato et al. 2017). As a definition of bioeconomy (Fig. 1), Carus and Dammer 2018reported that
bioeconomy compiles the production of renewable biological resources and the revalorisation of these sources for
developing high value-added products, such as food, feed,
bio-based products, and bioenergy (Carus and Dammer
2018).
This concept can be applied to countless industries, but
particularly in food and cosmetic sectors, there is a high
interest in green and sustainable approaches that could
totally or partially replace current synthetic compounds for
active ingredients obtained from natural sources. In this
sense, agro-industrial wastes are a source of bioactive
compounds, which can cause such wastes to be reused and
revalued by means of the following applications (Gordobil
et al. 2020).
2.1 Bioenergy
Bioenergy includes biofuels and biomass which are considered a solution to address future shortages and rising
fossil fuel prices. In this field, in order to avoid the
competition between energy and food production, a
second-generation of bioenergy from agro-industrial residues is gaining global recognition for their potential of
providing sustainable bioenergy (Tonini et al. 2016). As it
is well known, agro-industrial by-products contain
important amounts of carbon, macro- and micronutrients
that could be used for bioenergy production. In literature,
there are many examples of the use of these
agro-industrial residues in this field. For example, in
Ghana, tropical fruit (pineapple and mango), and cocoa
residues are used as a substrate in biogas production,
reducing dependence on grid electricity and synthetic
fertilisers and maintaining soil carbon levels (Kamp and
230
Á. Fernández-Ochoa et al.
generation, for composting, or in specific cases, for animal
feed. However, these agro-industrial wastes have been
characterised by containing nutrients (vitamins, minerals,
trace elements), dietary fibres, enzymes, oils, and bioactive
compounds (phenolic compounds, carotenoids, glucosinolates, and flavonoids) (Sagar et al. 2018; Saini et al. 2019).
The interest in bioactive compounds has increased in recent
decades due to their great abundance in the plant kingdom as
well as their multiple beneficial properties to prevent and be
beneficial against a large number of pathologies such as
cancer, cardiovascular, neurodegenerative diseases, and
inflammation (Altemimi et al. 2017; Fernández-Ochoa et al.
2020).
Since large amounts of agri-food are considered
non-edible food or waste because they do not complete the
established standards for their commercialisation, large
quantities of food by-products are generated throughout the
supply chain from the initial steps to the final consumption
stages (Torres-Valenzuela et al. 2020). In this scenario, the
presence of bioactive compounds makes it possible to use
them for the development of high added value products such
as functional foods, nutraceuticals, cosmeceuticals, or
applications in the textile or pharmaceutical industries. To
isolate these phytochemical compounds, a sophisticated step
of extraction has to be carried out to use them later in the
potential applications related to high added value products
(Kumar et al. 2017). For this objective, different extraction
strategies have been optimised to do this process more
sustainable, such as ultrasound-assisted extraction (UAE),
subcritical water extraction (SWE), microwave-assisted
extraction (MAE), supercritical fluid extraction (SFE), or
enzyme-assisted extraction (EAE) (Marić et al. 2018).
The possibility of reusing agro-industrial wastes for the
elaboration of high added value products reduces the environmental impact but also represents an attractive proposal
for companies that can generate new alternative ways of
business opportunities. These types of strategies, defined as
a circular economy, have been related to the sustainable
development goals and are increasingly being implemented
by companies in recent years (Sauvé et al. 2016;
Rodriguez-Anton et al. 2019).
In this chapter, the potential applications of high added
value products obtaining from the reuse of agro-industrial
waste and the role that these applications can have in the
bioeconomy of companies and in strategies against climate
change are presented. In addition, the main agro-industrial
wastes from vegetables, fruits, or cereals are described, as
well as the main phytochemical compounds present in them
and the green extraction techniques to isolate these
phytochemicals.
2 The Role of Agro-Industrial Wastes
in Bioeconomy
Globally, large amounts of agro-industrial wastes and
by-products, which can be ‘on/off farm’ contribute to environmental stress. However, sustainable development has to
do with a movement of building on ‘circular economy’ or
‘bioeconomy’ by high value-added products based on
agro-industrial waste recycling. Moreover, it could align
with the achievement of carbon neutrality and the obtainment of the UN Sustainable Development Goals
(El-Chichakli et al. 2016).
Regarding the terms, there are different concerns about
Green, Circular, and Bio-economy, but despite the differences, they have common economic, environmental, and
social aims (D’Amato et al. 2017). As a definition of bioeconomy (Fig. 1), Carus and Dammer 2018reported that
bioeconomy compiles the production of renewable biological resources and the revalorisation of these sources for
developing high value-added products, such as food, feed,
bio-based products, and bioenergy (Carus and Dammer
2018).
This concept can be applied to countless industries, but
particularly in food and cosmetic sectors, there is a high
interest in green and sustainable approaches that could
totally or partially replace current synthetic compounds for
active ingredients obtained from natural sources. In this
sense, agro-industrial wastes are a source of bioactive
compounds, which can cause such wastes to be reused and
revalued by means of the following applications (Gordobil
et al. 2020).
2.1 Bioenergy
Bioenergy includes biofuels and biomass which are considered a solution to address future shortages and rising
fossil fuel prices. In this field, in order to avoid the
competition between energy and food production, a
second-generation of bioenergy from agro-industrial residues is gaining global recognition for their potential of
providing sustainable bioenergy (Tonini et al. 2016). As it
is well known, agro-industrial by-products contain
important amounts of carbon, macro- and micronutrients
that could be used for bioenergy production. In literature,
there are many examples of the use of these
agro-industrial residues in this field. For example, in
Ghana, tropical fruit (pineapple and mango), and cocoa
residues are used as a substrate in biogas production,
reducing dependence on grid electricity and synthetic
fertilisers and maintaining soil carbon levels (Kamp and
230
Á. Fernández-Ochoa et al.