additives are incorporated into chitosan solutions. Some of these studies are summarized in Table 2.2. Lekjing [130] employed clove oil, an essential oil with antimicrobial and antioxidant properties, to coat pork sausages by dipping and microbiological, physical, and chemical analyses as well as sensory evaluation were carried out. It was demonstrated that the coating inhibited the microbial growth, retarded the lipid oxidation, and extended the shelf life of the product during refrigerated storage. However, negative impacts were found on odor and taste qualities. Other essential oils, such as that extracted from oregano, have also been incorporated into chitosan solutions to provide coatings with active properties. Paparella et al. [131] added oregano essential oil into chitosan solutions to coat fresh pork fillets and found that oregano had antimicrobial properties against meat spoilage bacteria, such as Brochothrix thermosphacta and Pseudomonas spp. In another study, Alsaggaf et al. [127] analyzed the effect of edible chitosan coatings applied by immersion of Nile tilapia fillets into chitosan solutions with pomegranate peel extract, an extract that has several bioactive phytochemicals for antimicrobial or food preservative applications. Composition, microbiological, antioxidant, total nitrogen volatile base value, and sensory analyses demonstrated that chitosan/pomegranate peel extract coatings were effective at extending the shelf life of fish fillets.
Table 2.2 Chitosan‐based active films and coatings.
| Food packaged | Packaging | Bioactives | Bioactivity | References |
|---|---|---|---|---|
| Cherry tomatoes and grapes | F | Tannic acid | AO + AM | [124] |
| White shrimp (Litopenaeus vannamei) | C | ɛ‐Polylysine | AM | [125] |
| Bread slices | F | Apricot kernel essential oil | AO + AM | [113] |
| Chicken | F | Schinus terebinthifolius Raddi (pink pepper) extract/peanut skin extract | AO | [126] |
| Nile tilapia fillets | C | Peels of pomegranate extracts | AM | [127] |
| Grass carp (Ctenopharyngodon idellus) | C | Glycerol monolaurate | AM | [128] |
| Yellow croakers | C | Nisin | AM | [129] |
| Pork sausages | C | Clove oil | AO + AM | [130] |
| Tomatoes | C | Iodide | AM | [116] |
| Pork fillets | C | Origanum vulgare essential oil | AM | [131] |
| Pacific mackerel (Pneumatophorus japonicus) fillets | C | Gallic acid | AO + AM | [132] |
| Chicken breast | C | Zataria multiflora essential oil/pomegranate juice | AO + AM | [133] |
C, coating; F, film; AO, antioxidant; AM, antimicrobial.
In addition to coatings, chitosan films have been used to wrap food products with the aim of prolonging food shelf life. Serrano‐León et al. [126] wrapped chicken products using chitosan films incorporated with peanut peel extract or pink pepper by‐products. Peanut peel extract contains proanthocyanidins and procyanidins, phenolic compounds with antioxidant activity, while pink pepper by‐products are composed of vitamin C, phenolic compounds, flavonoids, and carotenoids. The characterization of the chicken product was carried out analyzing chicken pH and color, peroxide value, thiobarbituric acid reacting substances (TBARS), and microbiological parameters. None of the additives altered chicken pH or color, but pink pepper by‐products showed greater antimicrobial and antioxidant activities than peanut peel extract.
2.4 Future Perspectives and Concluding Remarks
The amount of biowaste generated by food processing industries is huge. This biowaste can be valorized to obtain raw materials for the production of food packaging, reducing the use of nonrenewable and nonbiodegradable materials in line with the sustainability principles. In particular, proteins such as collagen and gelatin can be obtained from fishery waste and by‐products, but also active compounds can be extracted from other food processing wastes or by‐products in order to develop novel active packaging to extend food shelf life and reduce food losses. A review of the most employed methods to extract biopolymers from fishery waste, comparing benefits and drawbacks of the use of chemical and enzymatic processes, has been provided. In relation to film and coating production, wet (solution casting, spraying, dipping) and dry processes (compression molding, extrusion) have been mentioned in this chapter, highlighting the potential of dry processes for scaling‐up production. Also, the characterization of the most relevant properties of the films and coatings developed using fish gelatin and chitosan has been reported in order to give information on an appropriate selection of the most suitable material for specific food products. In particular, properties related to food quality and food life‐extension have been highlighted by means of the use of natural antioxidants and antimicrobials. Although further research is still needed, mainly to scale production at competitive costs, the valorization of food processing biowaste to produce active packaging could become a suitable approach toward more sustainable food packaging.
References
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6 6