1. Introduction
Active packaging has received a huge amount of attention for its antioxidant and antimicrobial properties to increase the shelf-life of food products. Several approaches have been introduced by incorporating antioxidant and antimicrobial compounds to improve the bioactivity of biomaterials used for packaging. Essential oils (EOs) and plant extracts are regarded as proper alternatives to artificial food additives in bioactive films for preservation because of their safety and outstanding antioxidant and antimicrobial activities
[1][119]. For example, the antimicrobial activity of chitosan film was significantly increased with the integration of melaleuca essential oil (MEO) and clove essential oil (CEO)
[2][107]. Similarly, the antioxidant activity of pullulan-based film was increased with rockrose essential oil incorporation
[3][106]. Other researchers, like Luís, Pereira
[4][116] and Yuan, Chen
[5][120], also reported the ability of essential oils to protect different types of food against oxidation and pathogenic and spoilage microorganisms. Bioactive films having essential oils were used for the preservation of these food products.
2. Fruits and Vegetables
Agricultural products, especially fruits and vegetables, are highly perishable postharvest in the natural environment; thus, their preservation is an ongoing problem for the food industry. Deterioration of fruit and vegetables occurs as a result of water loss, high respiration rates, microbial invasion, and oxidation. Therefore, it is crucial to create a suitable system to extend the post-harvest storage period and ensure the quality of fruits and vegetables
[6][121]. Recently, bioactive films with essential oils have received substantial consideration as an efficient, easy, and affordable method to slow down the deterioration of fruits and vegetables
[7][122]. The antimicrobials (essential oils) are embedded in active films, allowing the active biocide compounds to be released from the packaging for a longer period, extending the effects during food transport and storage
[8][123]. Cassava starch-based film supplemented with clove EO showed antifungal activity against
C. musae and
C. gloeosporioides. The film preserved the quality and reduced weight loss of banana varieties such as BRS Tropical, Prata-Anã, BRS Conquista, and Grand Nine during storage
[9][124]. PLA and poly (3-hydroxybutyrate-4-hydroxybutyrate) film containing angelica EO demonstrated better antioxidant ability, which effectively retarded the oxidation process by preventing LOX and PPO enzymatic activity in peaches and extended their shelf-life without compromising quality for more than 15 days
[8][123]. Zhou, He
[10][114] developed carboxymethyl chitosan/pullulan composite film supplemented with galangal essential oil, which effectively preserved mango fruits regarding fruit weight loss, firmness, TSS, and TA for 9 days compared to control film at room temperature. The effect of the addition of different polysaccharides, like tragacanth gum, xanthan gum, gum arabic, and pullulan, on the release of thyme EO from chitosan was investigated by Lian, Shi
[11][125] to preserve nectarine fruit. Compared to other polysaccharides, gum arabic delayed thyme EO release and consequently reduced fruit lesions in nectarines compared to other polysaccharide-added films after 60 h of storage. Moreover, Passafiume, Tinebra
[12][126] used neem essential oil to preserve sliced mango for 9 days at 4 °C. Biodegradable multilayer chitosan/starch-based film with added cinnamon EO (0.33 g) reduced weight loss, retained the freshness and firmness of cherry tomatoes, and outperformed the antibacterial and preservative qualities of polyethylene film for two weeks of storage
[13][127]. Previously, methylcellulose and polycaprolactone/alginate-based composite film with essential oil supplementation considerably reduced
L. monocytogenes and
E. coli growth in fresh broccoli during short-term storage
[14][128]. Similarly, the antimicrobial activity of gelatin-based film was improved against
E. coli and
S. aureus with the integration of banana leaf EO and preserved cherry tomatoes during 14 days of storage time, as reported by Kamari, Halim
[15][129]. The application of thyme EO in sweet potato starch film was investigated for spinach leaves
[16][130]. The numbers of
Salmonella typhimurium and
Escherichia coli in fresh spinach leaves were reduced with EO incorporation from the levels that were expected in five days and the shelf-life of spinach was enhanced. Some other fruits and vegetables preserved through bioactive films having essential oils are summarized in
Table 1.
3. Meat and Its Products
Meat and its products are perishable due to the presence of high nutrient content, moisture content, endogenous proteases, and neutral pH, creating ideal conditions for bacterial and biochemical deterioration. The incorporation of bioactive compounds such as essential oils into packaging materials to extend the shelf-life of meat has become an effective method. There have been several reports about the use of active films for meat and meat product preservation. Mung bean protein isolate/pullulan film used for the preservation of minced beef showed improved antimicrobial and antioxidant properties with the addition of marjoram (
Origanum majorana L.) essential oil (MEO). Compared to the control film, it reduced the bacterial population and chemical properties (TBARS, TVB-N, and pH) of minced beef after 14 days of storage time, indicating protective effects to increase the shelf-life
[17][131]. The supplementation of starch-based edible film with torch ginger (
Etlingera elatior Jack) inflorescence essential oil (TGIEO) enhanced its antibacterial and antioxidant properties and increased chicken meat shelf-life by presenting a lower coliform count and TBARS value during a storage period of 6 days
[18][132]. Chitosan (CH) blended with MMT-based nanocomposite film extended poultry meat shelf-life by controlling its TBARS, pH, and color
[19][133]. Later that year, in 2019, these researchers created a rosemary EO (REO)-enriched CH/MMT matrix to preserve raw poultry meat
[20][134]. The bioactive film demonstrated lower O
2 permeability and better antibacterial properties by reducing bacterial populations, lipid oxidation, and discoloration of poultry.
Chitosan-based edible film showed enhanced inhibitory effects against coliform bacteria, TVC, and PTC with the incorporation of Trachyspermum ammi EO, which subsequently extended the shelf-life of meat
[21][135]. Potato starch/apple peel pectin-based composite film containing microencapsulated
Zataria multiflora essential oil and ZrO
2 nanoparticles was used for quail meat packaging. The chemical characteristics of quail meat wrapped in active film showed the positive impact of encapsulated essential oil and ZrO
2 nanoparticles in extending its shelf-life
[22][98]. The supplementation of Cassava starch film with oregano essential oil demonstrated better antimicrobial and antioxidant activities to prevent the oxidation of ground beef
[23][136]. The resulting film preserved the meat against lipid oxidation for 3 days under refrigerated conditions. Likewise, the incorporation of lemongrass EO into cassava starch film also reduced microbial counts during storage
[24][137]. Shen, Zhou
[25][103] prepared
Dioscorea zingiberensis (DZW) starch film loaded with oregano essential oil (OEO), which presented better antioxidant activity and inhibited the growth of pathogenic bacteria in chicken meat for 7 days stored at 4 °C. Recently,
rwe
searchers used forsythia essential oil in ASKG-based film and extended the shelf-life of chicken and lamb meat for 9 and 12 days, respectively, when stored at 4 °C
[26][138]. These findings expressed the effectiveness of OEO-added DZW starch film in maintaining the quality and extending the shelf-life of fresh meat. Some other examples of meat and meat product preservation are given in
Table 1.
4. Fish and Fish Products
Fish and seafood are very important due to their nutritional value, popularity as a delicacy, and health benefits; however, their high moisture content, neutral pH, and large quantities of small molecules make them highly perishable by providing the perfect conditions for microbial and biochemical deterioration
[27][139]. Endogenous enzymatic reactions, microbial activity, and oxidation occur in fish shortly after death, so proper preservation methods should be adopted to preserve quality and increase shelf-life
[28][140]. Recently, natural preservatives have been the focus of fishery product preservation; in this regard, essential oils (EOs) are receiving huge attention owing to their impressive antimicrobial and antioxidant activities
[29][141]. Cao and Song
[30][142] developed Bombacaceae gum film having cinnamon leaf essential oil for fresh salmon fillet preservation. The POV and TBARS values of fish fillets wrapped in active film having essential oil were found to be lower compared to the control sample after 15 days at 4 °C, reflecting a reduction in lipid oxidation to extend the shelf-life of fish fillets. Similarly, starch and oregano essential oil (OEO)-integrated film was developed to prolong frozen fish fillet shelf-life
[31][143]. The addition of sage EO to gelatin, alginate, and chitosan-based film effectively retarded microbial growth, including
Shewanella spp.
A and
Pseudomonas spp., in fish burger stored at 4 °C
[32][144]. Similarly, rice starch film supplemented with oregano essential oil was used to preserve fish fillets. The active film displayed higher resistance against microbial growth and lipid oxidation in fish fillets during a storage time of 6 days
[31][143]. Fish packaged in Cassava starch film enriched with Citrus lemon peel extract demonstrated low total volatile basic nitrogen (TVB-N) and peroxide values compared to that packaged with the control film
[33][145]. Soy protein isolate, montmorillonite, and clove EO-based nanocomposite film was used for bluefin tuna (
Thunnus thynnus) fillet preservation. The active film reduced lipid oxidation and decreased the final counts of MBC, HSPB, TVC,
Enterobacteriaceae, and
Pseudomonas spp. during a storage time of 16 days under refrigerated conditions
[34][146]. Some of the other applications of active films having essential oils are summarized in
Table 1.
5. Dairy Products
Milk and other dairy products, including cream, fermented cheese, yogurt, etc., are good sources of nutrients for growth and health maintenance
[35][91]. However, several extrinsic factors like microorganisms, oxygen, moisture, and light can have detrimental effects on dairy products, including microbial deterioration, oxidation, undesirable odor, and discoloration
[36][147]. The use of active films on dairy products assists in preventing unwanted changes during handling and storage. Many researchers have reported the application of active films in the preservation of dairy products. Seydim, Sarikus-Tutal
[37][90] indicated that whey protein (WPI)-based film having garlic or oregano EO applied to Kasar sliced cheese restricted microbial growth, assuring a 15-day shelf-life of the product. Likewise, cinnamon EO was added to sodium alginate-based film to increase the shelf-life of paneer under refrigerated conditions (4 °C). The film retarded microbial growth and maintained the texture and sensory properties of paneer for 13 days
[38][148]. The applications of active films having EOs in dairy products are summarized in
Table 1.
6. Bread and Bakery Products
Bakery products are mostly consumed by people for breakfast all over the world, but they can be used to replace lunch and dinner. However, many bakery products like bread and cakes at room temperature have a limited lifespan of 3–5 days if no preservatives are used
[35][91]. Bakery products go through several chemical, microbial, and physical changes during their lifespan. The chemical and physical changes result in loss of freshness, crispness, and reduction in taste and texture, while microbial spoilage brings undesirable changes in appearance due to bacteria, mold, and yeast growth
[39][149]. Bioactive films not only prevent microbial growth but also maintain the texture of bakery products
[40][150]. The applications of active films having EOs in bakery products are summarized in
Table 1.
7. Nuts
During storage, nuts are prone to lipid oxidation, which can lead to undesirable taste, and smell, degradation of nutrients, and even produce some toxic chemicals
[41][151]. Studies have demonstrated that active films having antioxidants can prevent lipid oxidation in nuts and increase their shelf-life (
Table 1). Furthermore, active films prevent nuts from mechanical damage during stress and transportation, extending their shelf-life
[42][152].
Table 1.
Application of films having EOs for food packaging and preservation.