clove, and cinnamon are rich source of antimicrobial compounds. Major antimicrobial action mechanisms include disruption of phospholipid bilayer of cell membrane,
disruption of enzyme activity, effect on protein synthesis, and production of hydrogen peroxide [81, 82]. Antimicrobial properties of garlic, rosemary, and oregano
essential oils dispersed in whey protein isolate (WPI) films were tested against
Salmonella enteritidis, Lactobacillus plantarum, Staphylococcus aureus,
Escherichia coli, and Listeria monocytogenes by means of assay of zone of inhibition. Results indicated that the films incorporated with oregano oil (2%) were
observed to be effective against bacteria when compared with other spices [83]. In
a different study, essential oil of rosemary has been incorporated in chitosan films,
and it showed effective antibacterial activity against bacteria like Streptococcus
agalactiae and Listeria monocytogenes [84]. Biodegradable trays (polyvinyl alcohol
and cassava bagasse) containing oregano and clove essential oils were manufactured
by two methods: direct incorporation (6.5–10.0%) and surface coating (2.5–7.5%);
high antimicrobial activities were observed for surface-coated trays against spoilage
yeasts, molds, and Gram-negative and Gram-positive bacteria [85]. Electrospun
polyvinyl alcohol/β-cyclodextrin(PVA/CEO/β-CD)/cinnamon essential oil
nanofibrous antimicrobial film has shown effective antimicrobial activity against
Escherichia coli and Staphylococcus aureus with MBC of approximate 7–8 mg/mL
and MIC of 0.9
À1 mg/mL [86]. Dextrin-based nanosponges incorporated with
coriander essential oil (CEO) have shown significant bactericidal effect against
food safety pathogens. Authors reported that whole essential oils incorporated in
nanosponges (CD-NS) displayed efficient ability in controlling the oil release, while
restraining bacterial growth, hence providing a promising strategy in overcoming the
inefficiency of present antimicrobial food packages [87].
3.2 Antioxidant Release
Antioxidants are utilized into active packaging films to maintain oxidation stability
of lipids and to prolong shelf life of dried products and O 2 -sensitive foods. Natural,
synthetic, and nanoparticle-based antioxidants have been successfully developed
into multiple layer films. The synthetic antioxidants like thioester, butylated
hydroxytoluene, and organophosphates sometimes migrate into food products,
thereby creating potential toxicity issues, and due to this, the usage of such antioxidants are restricted in active packaging [88]. Hence, such artificial additives are
currently replaced with natural alternatives like essential oils and plant extracts
which exhibit antioxidant properties. The oxidative damage caused to foods can be
reduced by employing edible-coated films which does it by reducing the oxygen
transmission rate. The selection of bioactive compound depends on its compatibility
with the packaging. For example, food packaging material ethylene vinyl alcohol
copolymer (EVOH) matrix incorporated with antioxidants like quercetin, ferulic
acid, green tea extract, and ascorbic acid had significantly decreased water permeability. Moreover, green tea extract incorporated films has shown great protection
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B. Srinivasan and G. Kulshreshtha
disruption of enzyme activity, effect on protein synthesis, and production of hydrogen peroxide [81, 82]. Antimicrobial properties of garlic, rosemary, and oregano
essential oils dispersed in whey protein isolate (WPI) films were tested against
Salmonella enteritidis, Lactobacillus plantarum, Staphylococcus aureus,
Escherichia coli, and Listeria monocytogenes by means of assay of zone of inhibition. Results indicated that the films incorporated with oregano oil (2%) were
observed to be effective against bacteria when compared with other spices [83]. In
a different study, essential oil of rosemary has been incorporated in chitosan films,
and it showed effective antibacterial activity against bacteria like Streptococcus
agalactiae and Listeria monocytogenes [84]. Biodegradable trays (polyvinyl alcohol
and cassava bagasse) containing oregano and clove essential oils were manufactured
by two methods: direct incorporation (6.5–10.0%) and surface coating (2.5–7.5%);
high antimicrobial activities were observed for surface-coated trays against spoilage
yeasts, molds, and Gram-negative and Gram-positive bacteria [85]. Electrospun
polyvinyl alcohol/β-cyclodextrin(PVA/CEO/β-CD)/cinnamon essential oil
nanofibrous antimicrobial film has shown effective antimicrobial activity against
Escherichia coli and Staphylococcus aureus with MBC of approximate 7–8 mg/mL
and MIC of 0.9
À1 mg/mL [86]. Dextrin-based nanosponges incorporated with
coriander essential oil (CEO) have shown significant bactericidal effect against
food safety pathogens. Authors reported that whole essential oils incorporated in
nanosponges (CD-NS) displayed efficient ability in controlling the oil release, while
restraining bacterial growth, hence providing a promising strategy in overcoming the
inefficiency of present antimicrobial food packages [87].
3.2 Antioxidant Release
Antioxidants are utilized into active packaging films to maintain oxidation stability
of lipids and to prolong shelf life of dried products and O 2 -sensitive foods. Natural,
synthetic, and nanoparticle-based antioxidants have been successfully developed
into multiple layer films. The synthetic antioxidants like thioester, butylated
hydroxytoluene, and organophosphates sometimes migrate into food products,
thereby creating potential toxicity issues, and due to this, the usage of such antioxidants are restricted in active packaging [88]. Hence, such artificial additives are
currently replaced with natural alternatives like essential oils and plant extracts
which exhibit antioxidant properties. The oxidative damage caused to foods can be
reduced by employing edible-coated films which does it by reducing the oxygen
transmission rate. The selection of bioactive compound depends on its compatibility
with the packaging. For example, food packaging material ethylene vinyl alcohol
copolymer (EVOH) matrix incorporated with antioxidants like quercetin, ferulic
acid, green tea extract, and ascorbic acid had significantly decreased water permeability. Moreover, green tea extract incorporated films has shown great protection
120
B. Srinivasan and G. Kulshreshtha