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The aim of this study was to evaluate the effect of the incorporation of water-in-oil-in water (W/O/W) double emulsion (DE) loaded with “pitanga” leaf hydroethanolic extract on the physicochemical, antimicrobial and antioxidant properties of films based on gelatin, chitosan and gelatin/chitosan blend to target the future application of these films as active food packaging. Scanning electron microscopy and atomic force microscopy images of the films showed that the presence of DE caused heterogeneity on the surface and internal structure. As a consequence, the decrease in the gloss and the water drop contact angle of films was caused mainly by the increase in surface roughness. In addition, the DE significantly improved the UV/Vis light barrier property of the films. The DE increased the strength and stiffness of the films based on gelatin and chitosan, but decreased those properties in the gelatin/chitosan blend, and increased the extensibility of all films, in addition to decreasing water solubility, water vapor permeability and opacity. Films with DE showed high antioxidant activity, but only the films based on gelatin and with DE inhibited Staphylococcus aureus. The other films containing DE inhibited the growth of Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella ssp bacteria just in the region of contact with the films.

Starches are widely used in food processing, and their rheological properties are affected by thermal conditions imposed during the process. The objective of the present study was to assess the rheological behavior of jackfruit seed starch (JSS) dispersions, with a particular interest on the effects of the starch extraction techniques using either water or an alkali solution (0.1 M sodium hydroxide) as solvents. The analyses on the starches were performed using small amplitude oscillatory shear tests, including frequency, temperature, and time sweeps, and determining flow curves at different temperatures (10–40 °C). JSS dispersions were classified as weak-intermediary gels, and those prepared with JSS extracted with water showed higher values of G’ and G” in all of the tested samples. All gelatinized samples exhibited viscoelastic behavior, and with increasing temperatures the storage and loss moduli increased until a maximum value before reaching a plateau. Gelatinization temperatures were slightly lower for dispersions prepared with JSS extracted with water. Gelatinization kinetics showed that increasing temperatures caused a reduction in the time to achieve gelatinization. The JSS dispersions displayed thixotropic behavior, which was influenced by their concentration and the extraction method employed. The flow curves exhibited pseudoplastic behavior. The Power Law model was used to describe the JSS dispersions rheological behavior, which enabled to assess the effects of starch concentration and extraction method on their rheological properties.

The aim of this research was to study the effects of laponite concentrations on some properties of nano-biocomposite films based on cassava starch, focusing mainly the relation between the properties of the surface microstructure and roughness, water contact angle and gloss. Nano-biocomposite films were produced by casting. We analyzed gloss, color, opacity, water contact angle, crystallinity by X-ray diffraction, and microstructure by scanning electron microscopy and atomic force microscopy. Texture parameters (energy, entropy and fractal dimension) were extracted from micrographs. We observed a great impact of laponite in the morphology of nano-biocomposite films. Texture parameters correlated with surface heterogeneity and roughness. Finally, surface roughness affected the surface hydrophilicity of nano-biocomposite films. Laponite platelets were exfoliated and/or intercalated with amylose and amylopectin chains. This research reports new information on the effects of laponite concentrations on the morphological, optical and wetting properties of nano-biocomposite films aiming future industrial applications.

Two main varieties of jackfruit (soft and hard) are commonly known in Brazil and contain a large amount of starch. This work aimed to evaluate the effect of extraction methods (aqueous and alkaline treatments) on the structural and physicochemical properties of starches from soft and hard jackfruit (Artocarpus heterophyllus) seeds. The jackfruit seed starch (JSS) granules were small (6.4–11.1 μm diameter), round, and bell-shaped with a smooth surface. Apparent amylose content ranged from 24 32% and was higher for the soft variety, which influenced several properties. The starches exhibited A-type XRD patterns, which contributed to the high peak gelatinization temperatures (72–81 °C), and a crystallinity index ranging between 9.3–36.9%. Peak viscosities (2362–3373 cP) were similar to cassava starch. However, irrespective of the extraction method, the hard JSS had relatively higher pasting properties (peak viscosity and breakdown), swelling power, and solubility index (90 °C) when compared to the soft JSS, which could be associated with the lower amylose content. Significant differences in lipid, protein, and amylose contents were observed in all starches extracted with the NaOH solution. The alkaline solvent decreased the average particle size of JSS by about 36%, probably causing a chemical gelatinization. Additionally, NaOH significantly reduced the crystallinity index and caused minor changes in granule morphology and swelling power.

Both gelatin and poly(vinyl alcohol) (PVA) can be cross linked with glutaraldehyde (GLU). In the case of gelatin, the GLU reacts with each e-NH2 functional group of adjacent lysine residues, while for PVA, the GLU reacts with two adjacent hydroxyl groups, forming acetal bridges. Thus it can be considered possible to cross link adjacent macromolecules of gelatin and PVA using GLU. In this context, the aims of this work were the development of biodegradable films based on blends of gelatin and poly(vinyl alcohol) cross linked with GLU, and the characterization of some of their main physical and functional properties. All the films were produced from film-forming solutions (FFS) containing 2 g macromolecules (PVA + gelatin)/100 g FFS, 25 g glycerol/100 g macromolecules, and 4 g GLU (25% solution)/100 g FFS. The FFS were prepared with two concentrations of PVA (20 or 50 g PVA/100 g macromolecules) and two reaction temperatures: 90 or 55 °C, applied for 30 min. The films were obtained after drying (30 °C/24 h) and conditioning at 25 °C and 58% of relative humidity for 7 days, and were then characterized. The results for the color parameters, mechanical properties, phase transitions and infrared spectra showed that some chemical modifications occurred, principally for the gelatin. However, in general, all the characteristics of the films were either typical of films based on blends of these macromolecules without cross linking, or slightly higher. A greater improvement in the properties of this material was probably not observed due to the crystallinity of the PVA, which has a melting point above 90 °C. The presence of microcrystals in the polymer chain probably reduced macromolecular mobility, hindering the reaction. Thus more research is necessary to produce biodegradable films with improved properties.