![]() Similar results were found by Nowzari et al. They observed that the addition of chitosan to the film formulation yielded coatings with antimicrobial activity that were able to reduce aerobic plate counts over the course of the storage period. (2007) evaluated the effect of gelatin-based edible films on the microbial spoilage of cold-smoked sardine over 20 days of storage at 5☌. Silver–copper nanoparticles had the same positive effect on the antimicrobial properties of fish skin gelatin films and were also able to improve their mechanical ant thermal properties ( Arfat et al., 2017).Ĭhitosan is another agent that has been added to fish gelatin–based films due to its antimicrobial action against a variety of fungi and Gram-positive and Gram-negative bacteria ( Dutta et al., 2009). The authors showed their antimicrobial activity against L. monocytogenes and P seudomonas aeruginosa, as assessed by the agar diffusion method, and suggested their use provides safety and extends the shelf life of packaged foods. The effect of basil leaf essential oil and zinc oxide nanoparticles on the antimicrobial activity of films based on tilapia skin and fish protein isolate was evaluated by Arfat et al. (2006), who suggested lysozyme is a promising enzyme in retaining antibacterial activity and inhibiting bacterial contaminants. (2013) added GTE to the same source of gelatin film and achieved films that enhanced the total phenolic content, DPPH radical scavenging activity, and reducing power of the films.Īntimicrobial fish skin gelatin films were also obtained by Bower et al. (2014a,b) incorporated extracts from green tea, grape seed extract, gingko leaf, and ginger into silver carp gelatin films and obtained antioxidant films as confirmed by DPPH radical scavenging activity and ferric ion reducing capacity. The addition of a variety of natural extracts from murta leaves ( Gómez-Guillén et al., 2007), borage ( Gómez-Estaca et al., 2009a), brown algae ( Haddar et al., 2012), and oregano and rosemary ( Gómez-Estaca et al., 2009d) has also been carried out to investigate their effect on the antioxidant activity of films. ![]() Additionally, film solubility, WVP, transparency, and tensile strength decreased by adding the oils ( Ahmad et al., 2012). Bergamot and lemongrass oil were added to gelatin film from the skin of unicorn leatherjacket, which resulted in antimicrobial films in a concentration-dependent manner. In general, films added with oil had lower values of tensile strength and WVP than the control film. (2012) demonstrated that fish skin gelatin film added with lime oil had the highest ferric reducing antioxidant power and ABTS radical scavenging activity in comparison to bergamot, kaffir, and lemon oils. Active fish gelatin films have been produced by the addition of essential oils, such as clove, fennel, cypress, lavender, thyme, herb-of-the-cross, pine and rosemary, cinnamon, ginger, turmeric, plai, and Morinda citrifolia ( Gómez-Estaca et al., 2010 Lee et al., 2016c Maryam Adilah and Nur Hanani, 2016 Tongnuanchan et al., 2013 Wu et al., 2015).Ī study carried out by Tongnuanchan et al. To date, the development of antioxidant and/or antimicrobial fish gelatin films has drawn a lot of attention from researchers, mainly by introducing natural components into the polymer matrix. Crizel, in Reference Module in Food Science, 2017 Active Films The concentrated solution then goes through polish filtration to remove any unwanted substances and sterilized at an elevated temperature of 280–290☏ for 8–12 s, then chilled and finally dried and blended to get gelatin powder ( Karim and Bhat, 2009). IX.Įvaporating the neutralized gelatin solution to a concentration within 15%–45%. Optionally, to remove impurities, the aqueous solubilized gelatin solution then filtered through a cellulose/diatomaceous earth plate or frame filter and sequentially de-ionized through using a cationic-anionic resin bed. ![]() VII.Įxtracting the neutralized citric acid-treated fish skin with hot water at about 55☌ temperatures to solubilize partially degraded collagen materials. Washing the citric acid-treated fish skin solution with cold water until the solution is substantially neutral. Treating the neutralized fish skins with citric acid. ![]() Washing with water until the acid/alkali-treated skins are substantially neutral. ![]() Washing with plenty of water in order to remove excess acid or alkali and neutralized substantially with dilute aqueous mineral acid or alkali. I.Ĭleaning of the fish skins with cold water to remove substantially all the superfluous material and cutting into small size. Reproduced with major changes from Boran, G., Regenstein, J.M., 2010. A general flow diagram for fish gelatin production from fish skin. ![]()
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