The general objective of this thesis was “To develop and characterize biodegradable films
of fish gelatin combined with carboxymethyl cellulose and polyvinyl alcohol, added with
silver nanoparticles” and is structured into three chapters. The first chapter presents a
review article that serves as theoretical support for the research carried out, which is
entitled “Biodegradable polymeric blends of fish gelatin, carboxymethylcellulose and
polyvinyl alcohol used as active packaging: A review”. This manuscript provides an
overview of the main features and shortcomings related to the application of fish gelatin
in biodegradable films. It presents information that reports the production of films from
the combination of biopolymers as a good strategy to overcome their limitations,
highlights carboxymethylcellulose and polyvinyl alcohol as interesting polymers to form
mixed films with gelatin with improved properties and considers the possibility of
incorporating active compounds , particularly silver nanoparticles, to these polymeric
matrices with the aim of providing antimicrobial properties to the films and extending the
shelf life of packaged foods. The second chapter corresponds to the already published
article entitled “Effect of polyvinyl alcohol and carboxymethyl cellulose on the
technological properties of fish gelatin films”. In this study, biodegradable films were
produced by mixing gelatin/carboxymethyl cellulose (FG/CMC) and gelatin/polyvinyl
alcohol (FG/PVOH) in proportions 90/10, 80/20 and 70/30 with a total concentration of
3% (m/v) of solution and 10% (w/w polymers) of plasticizer, and the effect of adding
these polymers on the performance of fish gelatin films was evaluated. The results
showed that the mixture of gelatin with CMC and PVOH improved the mechanical
strength, water vapor barrier capacity and solubility of the films. The maximum CMC
concentration promoted the highest tensile strength, while the highest PVOH content
produced a film with lower solubility. FG/PVOH films were more flexible and water
resistant, but presented lower mechanical and thermal resistance compared to FG/CMC.
The proposed mixing systems proved to be suitable for improving the properties of fish
gelatin films. Chapter three presents the article “Optimization of the process for obtaining
a biodegradable nanocomposite film based on fish gelatin and carboxymethylcellulose
reinforced with silver nanoparticles”. The objective was to develop a biodegradable
nanocomposite film from fish gelatin (FG), carboxymethylcellulose (CMC) and silver
nanoparticles (NpAg). The formulation was optimized using response surface
methodology to establish the best levels of FG (2–4%), CMC (0.5–1%) and NpAg(0.005–0.01%) in order to obtain a film nanocomposite (FG/CMC-NpAg) with better
mechanical and barrier properties. The optimization was done based on the responses to
water vapor permeability (PVA), tensile strength (RT) and elongation (E). The optimized
conditions were: 3% FG, 0.54% CMC and 0.011% NpAg. The mechanical properties,
PVA, solubility, optical properties and light transmission of the optimized and control
films were analyzed. The optimized FG/CMC-NpAg film showed lower elongation and
transparency, but on the other hand demonstrated greater tensile and water resistance, as
well as improved barrier properties in relation to water vapor and ultraviolet light, when
compared to the control film. Overall, the results indicated that the biodegradable
nanocomposite film developed in this study may be suitable for use as packaging material.
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