Hydrocolloids from seaweeds have interesting functional properties, such as antioxidant activity and gelling ability. A polysaccharide was isolated by aqueous extraction at 90 C from the red seaweed Gracilaria birdiae (Gb), with a yield of 27.2% of the seaweed dry weight. The sulfate content of the polysaccharide was 8.4% and the main sugars present were galactose (65.4 mol%), 3,6-anhydrogalactose (25.1 mol%) and 6-O-methylgalactose (9.2 mol%). Gel permeation chromatography showed that Gb polysaccharide is a heterogeneous system, with molar mass at the main peak of 3.7 Â 10 5 g mol À1 and a shoulder of 2.6 Â 10 6 g mol À1. The sulfated polysaccharide of Gb characterized by FTIR exhibits the characteristic bands of agarocolloids (at 1375 and 770 cm À1). The rheological behavior of Gb sulfated polysaccharide exhibits a gel-like behavior close to the one observed in commercial agar. The antioxidant properties of Gb sulfated polysaccharide were evaluated by measuring DPPH freeradical scavenging effect, showing that this polysaccharide has a moderate effect in inhibiting the formation of those radicals.

The development of mixed systems, formed by locust bean gum (LBG), and k-carrageenan (k-car) can offer new interesting applications such as the development of edible films with particular properties. kcar/LBG blend films with different ratios were developed, and their effects on films' physical properties were assessed. Thermogravimetric analysis (TGA), X-ray diffraction (XRD) patterns, dynamic mechanical analysis (DMA) and Fourier-transform infrared (FTIR) spectroscopy techniques were used to highlight the interactions between the two polysaccharides. The addition of k-car to LBG improved the barrier properties of the films leading to a decrease of water vapor permeability (WVP). Improved values of elongation-at-break (EB) were registered when the ratio of k-car/LBG was 80/20 or 40/60 (% w/w). Moreover, the k-car/LBG blend films enhance the tensile strength (TS) compared to k-car and LBG films. FTIR results suggested that hydrogen bonds interactions between k-car and LBG have a great influence in films' properties e.g. moisture content, WVP. Therefore, different k-car/LBG ratios can be used to tailor edible films with enhanced barrier and mechanical properties.

This work presents a methodology for the extraction of galactomannans from seeds of four different species of Leguminosae (Adenanthera pavonina, Caesalpinia pulcherrima, Gleditsia triacanthos and Sophora japonica) to be used e.g. in the food and biomedical industries. The galactomannans were obtained by aqueous extraction followed by a precipitation with ethanol. This methodology is simpler and easier to perform than other existing extraction and purification methodologies, and because it avoids the use of organic solvents (other than ethanol), it is able to generate food grade substances and is environmentally friendlier. The yield of extraction in different stages of the process, monosaccharide composition, as well as physical and chemical parameters of the isolated galactomannans were determined and compared with previously published results. The mannose/galactose ratio of the extracted galactomannans ranged from 1.35 (A. pavonina) to 5.75 (S. japonica). The intrinsic viscosity ranged from 11.34 dL/g (C. pulcherrima) to 8.74 dL/g (S. japonica), while the viscosity average molecular mass ranged between 1.81 Â 10 6 Da and 1.17 Â 10 6 Da (A. pavonina > C. pulcherrima > G. triacanthos > S. japonica). The results confirm the suitability of the extraction and purification procedure to obtain galactomannans from non-traditional sources.

a b s t r a c tChitosan packaging films containing different bioactive compounds (a peptide fraction from whey protein concentrate (WPC) hydrolysate, glycomacropeptide (GMP) and lactoferrin) were produced and their mechanical and barrier properties were evaluated. The molecular weight of protein-based compounds was determined using SDS-PAGE. The addition of GMP and lactoferrin to chitosan film caused a significant reduction of tensile strength and the elongation-at-break significantly increased with the incorporation of lactoferrin. The addition of protein-based compounds also affected gas permeability: a significant decrease in water vapor permeability was observed with the incorporation of lactoferrin; oxygen permeability significantly decreased with the addition of GMP and lactoferrin and carbon dioxide permeability significantly decreased with the incorporation of all of the protein-based compounds. Such results were related with film's hydrophilicity and crystallinity.This manuscript contributes to the establishment of an approach to optimize edible films performance based on physico-chemical properties, aiming at a higher benefit for the consumer.

Hollow multilayer nanocapsules were successfully prepared through layer-by-layer assembly of two bioactive polysaccharides, chitosan and fucoidan. The stepwise adsorption of 10 chitosan/fucoidan layers and the consequent formation of a multilayer film on polystyrene nanoparticles (used as templates) were followed through ζ-potential measurement and the removal of the polystyrene core was confirmed by FTIR analysis. The chitosan/fucoidan nanocapsules morphology and size were evaluated by SEM and TEM, which showed that after the core removal, the nanocapsules maintained their spherical shape and a decrease of size occurred. A cationic bioactive compound, poly-L-lysine (PLL), was chosen to evaluate the loading and release behaviour of the nanocapsules. The chitosan/fucoidan nanocapsules showed a good capacity for the encapsulation and loading of PLL, which shows to be influenced by the initial PLL concentration and the method of encapsulation used. The results of fitting the linear superimposition model to the experimental data of PLL release suggest an anomalous behaviour, with one main polymer relaxation. The PLL release was found to be pH-dependent: at pH 2 relaxation is the governing phenomenon and at pH 7 Fick's diffusion is the main mechanism of PLL release. Chitosan/fucoidan nanocapsules is a promising delivery system for water soluble bioactive compounds, such as PLL, showing a great potential of application in food and pharmaceutical industries.

Innovations constantly appear in food packaging, always aiming at creating a more efficient quality preservation system while improving foods' attractiveness and marketability. The utilization of renewable sources for packaging materials, such as hydrocolloids from biological origin, is one the main trends of the industry. Edible films/coatings have been considered as one of the potential technologies that can be used to increase the storability of foods and to improve the existent packaging technology, helping to ensure the microbial safety and the preservation of food from the influence of external factors. In view of these recent developments, the main objective of this review is to provide information concerning the utilization of galactomannans in the production of edible films/coatings. The most important features of these polysaccharides are discussed, namely: their structure and applications; physical, chemical, thermal and mechanical properties of galactomannan-based films/coatings; transport properties (in particular those related to moisture, oxygen, carbon dioxide exchange through the films/ coatings); incorporation of active compounds (e.g. natural antimicrobials and/or antioxidants) and applications in food products. It is viewed that in a near future tailored edible packaging based on polysaccharides can be applied to selected foods, partially replacing non-biodegradable/non-edible plastics.

Micro- and nanoencapsulation is an emerging technology in the food field that potentially allows the improvement of food quality and human health. Bio-based delivery systems of bioactive compounds have a wide variety of morphologies that influence their stability and functional performance. The incorporation of bioactive compounds in food products using micro- and nano-delivery systems may offer extra health benefits, beyond basic nutrition, once their encapsulation may provide protection against undesired environmental conditions (e.g., heat, light and oxygen) along the food chain (including processing and storage), thus improving their bioavailability, while enabling their controlled release and target delivery. This review provides an overview of the bio-based materials currently used for encapsulation of bioactive compounds intended for food applications, as well as the main production techniques employed in the development of micro- and nanosystems. The behavior of such systems and of bioactive compounds entrapped into, throughout in vitro gastrointestinal systems, is also tracked in a critical manner. Comparisons between various in vitro digestion systems (including the main advantages and disadvantages) currently in use, as well as correlations between the behavior of micro- and nanosystems studied through in vitro and in vivo systems were highlighted and discussed here for the first time. Finally, examples of bioactive micro- and nanosystems added to food simulants or to real food matrices are provided, together with a revision of the main challenges for their safe commercialization, the regulatory issues involved and the main legislation aspects.

a b s t r a c tNanoemulsions present a high potential to be used in food products due to their advantages over conventional emulsions (e.g. higher stability to gravitational separation and droplet aggregation and enhanced bioavailability of encapsulated compounds), however their application to foods is hindered by some concerns about potential risks associated with their ingestion. The knowledge of the behaviour of nanoemulsions as well as the fate of bioactive compounds encapsulated within them in the gastrointestinal (GI) tract is of utmost importance to assess their safety for human consumption and to produce delivery systems that provide an optimized bioactivity of the encapsulated compound. In this work, a dynamic gastrointestinal model, comprising the simulation of stomach, duodenum, jejunum and ileum, was used to evaluate the behaviour of curcumin nanoemulsions stabilized by biopolymer emulsifiers (lactoferrin and lactoferrin/alginate multilayer structure) under GI conditions. The interfacial characteristics of curcumin nanoemulsions had a significant impact on their physicochemical stability within the simulated GI tract. Also, results suggested that alginate coating may be able to control the rate of lipid digestion and free fatty acids adsorption within the GI tract, but the encapsulated lipid is digested at the same extent, releasing the lipophilic bioactive compound. This work contributes to an improved understanding of how multilayer nanoemulsions behave within the GI tract and this knowledge will be useful for the optimization of delivery systems that improve the physicochemical stability of emulsions in food products, while still releasing encapsulated lipophilic bioactive compounds.