100
The WVP and mechanical strength of protein-based films are comparably lower
than the synthetic polymers such as low-density polyethylene (LDPE), ethylene
vinyl alcohol (EVOH) and cellophane. This is due to the hydrophilic structure of
proteins (Bourtoom 2009; Hernandez-Izquierdo and Krochta 2008). However, gas
(O 2 , CO 2 , and aroma) and water permeability of films are improved when the pH of
the solution is higher than the isoelectric point of the proteins (Olivas and BarbosaCánovas 2005). In addition, the inclusion of NPs such as nanocellulose, montmorillonite (Mt) and silver (Ag) NPs improves the water and oxygen barrier properties,
mechanical strength and thermal stability, in addition to providing antimicrobial
properties for the protein-based nanocomposite films (Bae et al. 2009; Kumar et al.
2010; Pereda et al. 2011; Kanmani and Rhim 2014; Qazanfarzadeh and
Kadivar 2016).
Zein films have a strong and glossy structure, resistant to grease, and cross linking
or the addition of glycerin improves the mechanical properties of these films
(Tharanathan 2003). Although the brittleness is reduced with the addition of plasticizer, the barrier properties (water vapor and gas) of zein-based films are negatively
affected (Arora and Padua 2010). Similar to zein, the addition of plasticizer reduces
the brittleness of whey protein films (Plackett 2011). But the type and ratio of plasticizer together with the storage environment are effective on oxygen permeability
values of whey protein-based films (Miller and Krochta 1997; Ramos et al. 2012).
6.2.3 Lipid and Wax Biomass
The first development of food coating was the manufacture of wax-based coating on
fruits to minimize dehydration and provide a bright appearance (Ansorena et al.
2018). Fat and oil-based biomasses such as bees, candelilla, carnauba and rice bran
waxes, lecithin, shellac, mineral and vegetable oils, stearic acid, lauric acid, glycerin, triolein, fatty acid sucrose esters and resins are examples of lipids and waxes
that are used in food packaging applications (Baldwin et al. 1995; Morillon et al.
2002; Rhim and Shellhammer 2005; Bonilla et al., 2012; Robertson, 2013).
Synthetic waxes such as paraffin and petroleum waxes are also used for food packaging (Robertson 2013). In addition to using the lipids as a matrix in biocomposites,
essential oils from plants are used as antimicrobial agent in composite films
(Debeaufort et al. 2000; Morillon et al. 2002; Bourtoom 2009).
Lipids and waxes are used in the composite films for their barrier properties
against water vapor (Rhim and Shellhammer 2005). The long fatty acid chains are
effective in reducing WVP values. However, fatty acid chains with more than 18
carbon atoms cause a negative effect on WVP values, due to heterogeneity in the
polymer structure (immiscible mixtures) (Morillon et al. 2002). Self-standing lipid
films have low processability due to their low mechanical strength (Rhim and
Shellhammer 2005). Although its strength may be improved with the addition of
hydrocolloids, either with lamination or making emulsions (Falguera et al. 2011).
Lipid-based films and waxes have low moisture permeability due to their
H. Cakmak and E. Sogut
The WVP and mechanical strength of protein-based films are comparably lower
than the synthetic polymers such as low-density polyethylene (LDPE), ethylene
vinyl alcohol (EVOH) and cellophane. This is due to the hydrophilic structure of
proteins (Bourtoom 2009; Hernandez-Izquierdo and Krochta 2008). However, gas
(O 2 , CO 2 , and aroma) and water permeability of films are improved when the pH of
the solution is higher than the isoelectric point of the proteins (Olivas and BarbosaCánovas 2005). In addition, the inclusion of NPs such as nanocellulose, montmorillonite (Mt) and silver (Ag) NPs improves the water and oxygen barrier properties,
mechanical strength and thermal stability, in addition to providing antimicrobial
properties for the protein-based nanocomposite films (Bae et al. 2009; Kumar et al.
2010; Pereda et al. 2011; Kanmani and Rhim 2014; Qazanfarzadeh and
Kadivar 2016).
Zein films have a strong and glossy structure, resistant to grease, and cross linking
or the addition of glycerin improves the mechanical properties of these films
(Tharanathan 2003). Although the brittleness is reduced with the addition of plasticizer, the barrier properties (water vapor and gas) of zein-based films are negatively
affected (Arora and Padua 2010). Similar to zein, the addition of plasticizer reduces
the brittleness of whey protein films (Plackett 2011). But the type and ratio of plasticizer together with the storage environment are effective on oxygen permeability
values of whey protein-based films (Miller and Krochta 1997; Ramos et al. 2012).
6.2.3 Lipid and Wax Biomass
The first development of food coating was the manufacture of wax-based coating on
fruits to minimize dehydration and provide a bright appearance (Ansorena et al.
2018). Fat and oil-based biomasses such as bees, candelilla, carnauba and rice bran
waxes, lecithin, shellac, mineral and vegetable oils, stearic acid, lauric acid, glycerin, triolein, fatty acid sucrose esters and resins are examples of lipids and waxes
that are used in food packaging applications (Baldwin et al. 1995; Morillon et al.
2002; Rhim and Shellhammer 2005; Bonilla et al., 2012; Robertson, 2013).
Synthetic waxes such as paraffin and petroleum waxes are also used for food packaging (Robertson 2013). In addition to using the lipids as a matrix in biocomposites,
essential oils from plants are used as antimicrobial agent in composite films
(Debeaufort et al. 2000; Morillon et al. 2002; Bourtoom 2009).
Lipids and waxes are used in the composite films for their barrier properties
against water vapor (Rhim and Shellhammer 2005). The long fatty acid chains are
effective in reducing WVP values. However, fatty acid chains with more than 18
carbon atoms cause a negative effect on WVP values, due to heterogeneity in the
polymer structure (immiscible mixtures) (Morillon et al. 2002). Self-standing lipid
films have low processability due to their low mechanical strength (Rhim and
Shellhammer 2005). Although its strength may be improved with the addition of
hydrocolloids, either with lamination or making emulsions (Falguera et al. 2011).
Lipid-based films and waxes have low moisture permeability due to their
H. Cakmak and E. Sogut