Os desafios ambientais colocados pelas embalagens de plástico convencionais, incluindo a acumulação de resíduos e a poluição, impulsionaram a procura de alternativas sustentáveis. Este estudo tem como objectivo estudar o potencial de três películas biodegradáveis – Ácido Poliláctico (PLA), Mater-bi® Home e Mater-bi® Industrial - como alternativas ecológicas aos plásticos tradicionais para embalagem de alimentos. Estes materiais foram caracterizados através de vários testes, em termos das suas propriedades mecânicas, permeabilidade ao vapor de água, absorção de óleo, capacidades de barreira aos raios UV e adequação à conservação de produtos alimentares, tais como bolachas e fiambre. Os resultados revelam que as películas de PLA apresentaram propriedades superiores de barreira ao vapor de água (WVP = 7,0 x 10-13 mol.m/m2sPa), maior resistência à tração (63,9 MPa) e maior proteção UV em comparação com as películas de Mater-bi®, tornando-as adequadas para aplicações que requerem durabilidade estrutural e proteção contra a luz. Em contrapartida, as películas de Mater-bi® eram mais flexíveis e dúcteis (deformação de 2,1), com a Mater-bi® Home a apresentar uma maior absorção de água (6,1%). Estudos de vida útil comparando PLA e polipropileno (PP) demonstraram que enquanto o PP superou o PLA na retenção de humidade, textura e cor tanto em biscoitos como em fiambre, o PLA proporcionou uma maior proteção contra alterações oxidativas quando a Parachlorella kessleri foi incluída nas formulações de fiambre. Este trabalho realça o potencial dos polímeros biodegradáveis como soluções de embalagem sustentáveis, enquanto salienta a necessidade de uma maior otimização para melhorar as suas propriedades de barreira e alargar a sua aplicabilidade.

Three‐dimensional (3D) bioprinting comprises a group of biofabrication technologies for the additive manufacturing of 3D constructs by precisely printing biocompatible materials, cells and biochemicals in predesigned spatial positions. These technologies have been successfully applied to fabricate biodegradable 3D constructs with intricate architectures and heterogeneous composition, assuming a pivotal role in the field of tissue engineering. However, the full implementation of bioprinting strongly depends on the development of novel biomaterials exhibiting fast crosslinking schemes and appropriate printability, cell‐compatibility and biomechanical properties. Photocrosslinkable hydrogels are attractive materials for bioprinting as they provide fast polymerization under cell‐compatible conditions and exceptional spatiotemporal control over the gelation process. Photopolymerization can also be performed during the bioprinting to promote the instantaneous formation of hydrogel with high well‐defined architecture and structural stability. In this review paper, we summarize the most recent developments on bioprinting of photocrosslinkable biodegradable hydrogels for tissue engineering, focusing on the chemical modification strategies and the combination of photocrosslinking reactions with other gelation modalities.

ABSTRACT The retainers of water in the soil can favor nitrogen (N) use efficiency in oat yield. The aim of the study was to determine if the conditions of use of the biopolymer hydrogel increase the fertilizer-N use efficiency in oat yield in succession systems of high and low residual-N release. In each succession system (soybean/oat, corn/oat), two experiments were conducted in 2014 and 2015, one to quantify biomass yield and the other to estimate grain yield and lodging. The design was randomized blocks with four replicates in a 4 x 4 factorial scheme for hydrogel doses (0, 30, 60 and 120 kg ha-1), added in the furrow with the seed, and N fertilizer doses (0, 30, 60 and 120 kg ha-1) applied in the fourth-expanded-leaf stage. The use of hydrogel increases N use efficiency in oat yield, especially under the conditions of 30 to 60 kg ha-1 of biopolymer; however, this effect is dependent on the succession system and on weather conditions.

ABSTRACT Edible films are an alternative to synthetic materials used for packaging foods. The aim of this study was to develop and characterize films made from cassava starch, freeze-dried acai and glycerol. The films were characterized for thickness, water vapor permeability, water solubility, anthocyanins, antioxidant capacity and mechanical properties. The results indicated a rich edible film in anthocyanins with considerable antioxidant capacity (150.70 micromol Trolox), which can extend the commercial validity of the packaged food and meets the growing demand for biodegradable packaging that tends to reduce the environmental impact. The addition results in a significant effect on the polymer matrix reducing the water solubility and water activity. The elongation test at rupture reported to be 17.738%, indicating that addition of pulp increased film flexibility.

This work aims to (1) produce and characterize the flour obtained from two varieties of canihua, cupi and illpa-inia, and (2) evaluate the ability of these flours to form biofilms. The flours produced contain proteins, starches, lipids, organic substances containing phenol groups, and high percentages of unsaturated fatty acids. Films produced from the illpa variety presented lower water vapor permeability and larger Young’s modulus values than the films formed from the cupi variety. Both films were yellowish and displayed a high light blocking ability (as compared with polyethylene films), which can be attributed to the presence of phenolic compounds. Furthermore, they showed lesser solubility and water permeability than other polysaccharide films, which may be the result of the higher protein (12%–13.8%) and lipid (11%) contents in canihua flours, as well as the formation of a larger number of S–S bonds. On the other hand, these films presented a single vitreous transition temperature at low temperatures (< 0 °C), crystallization of the A and Vh types, and an additional diffraction peak at 2 = 7.5º, ascribed to the presence of essential fatty acids in canihua flour. Canihua flour can form films with adequate properties and shows promise for potential applications in food packaging, because it acts as a good barrier to incident ultraviolet light.

In this article, films were produced with six types of cassava's starch mixed with gelatin and plasticized with sorbitol. These films were used in covering of grapes 'Benitaka' (Vitis vinifera L.) as biodegradable packaging. The acetylated starch film showed the best results in solubility, thickness and homogeneity, besides the less water loss the fruit, resulting in better coverage, increasing the shelf life fruits in 12 days. These results demonstrate the great potential of using films in food conservation, adding value to agricultural activity and helping to reduce non-biodegradable plastics in the environment.

A series of biodegradable graft copolymers were synthesized by grafting ε-caprolactone over dextran of different molecular weights. The obtained copolymers were characterized by Fourier transform infrared spectroscopy FTIR, proton nuclear magnetic resonance ¹H NMR, thermogravimetry and elemental analysis. Stable monolayers at the air-water interface and spin coated thin films were prepared and characterized by the Langmuir technique and by contact angle measurements respectively. The compressibility and static surface elasticity of the monolayers and the surface energy of copolymer thin films show dependence with the ε-caprolactone content. From these results it can be concluded that the surface properties of grafted copolymers can be modulated by their composition. Additionally, according to the obtained results, ε-caprolactone grafted-dextrans show potential for being used in different applications where surface properties are important.

Abstract The objective of this study was to develop films with reduced hygroscopicity and improved mechanical properties from acetylated cassava starch. For that, an acetylation procedure using acetic anhydride as the esterification reagent was performed, resulting in starch acetates with degrees of substitution (DS) of 0.6 (S0.6) and 1.1 (S1.1). Twelve films formulations were studied: native cassava starch (S), starch acetate S0.6 and S1.1, with two glycerol concentrations (0.25 g.100 g-1 (25) and 0.30 g.100 g-1 (30)). The films were conditioned at the relative humidities (RH) of 58% and 75% for 96 h before characterization. Water vapor permeability, water solubility, water sorption isotherms, microstructural analyses, and mechanical properties in different relative humidity and different glycerol concentration were performed. Starch acetate films (S1.1) resulted in lower water vapor permeability (2.35 ± 0.26 × 10-7g/m.s.Pa) and water solubility (21.2 ± 0.16 g.100 g-1) than native starch films (3.79 ± 0.26 × 10-7 g/m.s.Pa and 25.46 ± 0.12 g.100 g-1). S0.6 films showed higher tensile strength (8.42 ± 0.84 MPa) than S1.1 films (6.93 ± 0.55 MPa). The results indicated that acetylated starch can be used to produce films with improved mechanical properties, with less water solubility and permeability to water vapor, especially when starch acetate with 0.6 DS and low glycerol concentration are used. Chemical compounds used in this article: Starch, acetate (PubChem CID: 24832118); Acetic acid (PubChem CID: 176); Acetic anhydride (PubChem CID: 7918); Sulfuric acid (PubChem CID: 1118); Glycerol (PubChem CID: 753).

Abstract Antistatic packaging is a very important sector since the electrostatic discharge of electronic devices can damage and/or disable these products. In addition, it is essential to dispose of this packaging correctly. In this work, the synergistic effect of the addition of lignin and carbon black on the development of antistatic and biodegradable packaging was verified. In this study, PLA was mixed with lignin and carbon black and the composites were prepared using a high-speed thermokinetic homogenizer where the melting of the PLA and the blend with fillers occurred by friction. The composites were characterized by Izod impact tests, scanning electron microscopy, thermal properties, electrical characterization and biodegradation tests in garden soil. The results show that lignin is a great option to accelerate the biodegradation of PLA in the garden soil and the carbon black acts as an antistatic agent reducing the electrical resistivity of the composites.

The toxicity of residues formed during water treatment is mainly a function of the chemicals used. The inorganic flocculants, when used, give rise to compounds harmful to humans and to the environment. An alternative solution is the use of tannins. However, despite the environmental benefits, when using tannin-based products in the treatment of industrial water, modifications may be imparted to the final product. In this work, tannin was evaluated as flocculating agent to treat the water used in the emulsion polymerization to produce SBR. The results show that good stability of the latex and acceptable color in the rubber can be achieved.