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34 Agri and Food Waste Valorization Through the Production of Biochemicals and Packaging Materials

noted in the case of onion [60]. Certain seeds of leguminous plants can also be used

as protein supplements [61] during enrichment of foods.

Production of prebiotics employing spoilage fungus from AFW is another area

which is equally important and this aspect has been dealt elsewhere and readers are

directed to these research publications [62].

34.6

Biofuels

Under the biorefinery concept, the terminal use of AFW should be for either com-

posting or energy production after all the bioactive compounds have been recovered

from the wastes and after the cellulose, hemicelluloses and pectin have been utilized

in polymer composites.

Thermochemical solutions involve the conversion of AFW into liquid hydrocar-

bons by the application of heat. This valorizable means usually tend to convert AFW

into biofuel through the pyrolysis of agri-food residues into three fractions such as

bio-oils, biochar and biogas [63, 64], fast pyrolysis [65], hydrothermal liquefaction

[66], gasification [67], followed by Fischer–Tropsch synthesis [68].

Microorganisms are also used to convert AFW into biofuel. Microorganisms

acting on AFW can be either in an aerobic or anaerobic environment to degrade

organic wastes. When it is aerobic it is called composting and generates fertilizers,

while under anaerobic conditions it generates both fertilizers (digestate) and biogas

which is primarily 60–70% methane and 30–40% carbon dioxide. The development

of microbial fuel cells producing hydrogen in an anaerobic digestion process has

been attempted [69]. El Mekawy et al. [70] have explored food and agricultural

wastes as substrates for bioelectrochemical system achieving both waste treatment

and energy recovery.

34.7

Packaging Materials and Bioplastics

Packaging is a combination of technology and art to pack a commodity for safe

storage, convenient transport, and enhanced trade. Plastics form an essential part

of packaging in different forms and accounts for >30% of global plastic consump-

tion [71]. Plastics are mainly made from petroleum-based polymers and exist in

the environment for hundreds of years. It is a challenge to recycle the plastics due

to large differences in their varieties. Thus, a major part (80%) goes into landfills.

It is not a surprise that a small share (∼3%) ends up in the ocean also threaten-

ing life in water body. A serious concern from the above activities and increasing

consumer awareness prompted the packaging industry to seek bio-based alterna-

tives such as bioplastics that involve the use of renewable resources and reduce

the dependency on fossil fuels. Today, valorization of agriculture and food waste in

packaging is an upcoming research area and is gaining the attention of researchers

worldwide.