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Bio-composites are easy to manufacture and environmentally friendly, could reduce the overall cost and provide lightweight due to the low density of the natural fibers. In a bid to compete with the synthetic fiber reinforced composites, a single natural fiber composite may not be a good choice to obtain optimal properties. Hence, hybrid composites are produced by adding two or more natural fibers together to obtain improved properties, such as mechanical, physical, thermal, water absorption, acoustic and dynamic, among others. Regarding thermal stability, the composites showed a significant change by varying the individual fiber compositions, fiber surface treatments, addition of fillers and coupling agents. The glass transition temperature and melting point obtained from the thermomechanical analysis and differential scanning calorimetry are not the same values for several hybrid composites, since the volume variation was not always parallel with the enthalpy change. However, the difference between the temperature calculated from the thermomechanical analysis and differential scanning calorimetry was lower. Significantly, this critical reviewed study has a potential of guiding all composite designers, manufacturers and users on right selection of composite materials for thermal applications, such as engine components (covers), heat shields and brake ducts, among others.

The selected thermal and rheological properties of pumpkin starches were compared with values evaluated for corn and potato starch. The pumpkin starches had lower pasting temperatures (by near 3°C and 24°C than potato or corn starch respectively), the peak viscosity (nearly 2300mPas lower than potato starch) and higher final viscosities (by 80-120mPas than those for potato starch and by 1700mPas in relation to corn starch). The thermal profile of pumpkin starches examined by the DSC method were quite similar to those of potato starch but lower than those of corn. The retrogradation degree of pumpkin starch was lower by 5-26% than that for corn or potato starches. The thermal treatment of starches led to the formation of radicals. Pumpkin starches were less susceptible to the formation of radicals than potato starch and had less about 0.3-1.3×1015radicals/g than potato starch.

Made available in DSpace on 2020-12-12T01:48:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-04-15 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Native sweet potato starch was gelatinized at temperatures between 57 and 69 °C and then spray dried, to verify the changes caused by this process. The spray dried starch granules initially swelled with the increase in preheating temperature, displaying a larger diameter, but shrank upon colling. There was an increase in the gelatinization temperature and a decrease in the enthalpy change of the spray dried starches relative to those of native starch. Spray dried starch preheating at 69 °C showed highly reduced enthalpy change (80%) and relative crystallinity. Based on the parameters studied, the best preheating temperature was 67 °C. Under this condition, the starch can be applied in more viscous products that require a greater thickness, and with great process yield (65%). This study showed the feasibility of the application of this process to produce sweet potato starches with specific properties for different purposes in the food and non-food industries. Center for Tropical Roots and Starches (CERAT) College of Agronomic Science (FCA) São Paulo State University (UNESP) Department of Food Engineering and Technology Institute of Biosciences Language and Physical Sciences São Paulo State University (UNESP) Center for Tropical Roots and Starches (CERAT) São Paulo State University (UNESP) Center for Tropical Roots and Starches (CERAT) College of Agronomic Science (FCA) São Paulo State University (UNESP) Department of Food Engineering and Technology Institute of Biosciences Language and Physical Sciences São Paulo State University (UNESP) Center for Tropical Roots and Starches (CERAT) São Paulo State University (UNESP) CNPq: 302827/2017-0 CAPES: BEX 9551/14-0

Made available in DSpace on 2022-04-28T19:40:59Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-08-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Thermoplastic starch (TPS) is a widely studied biopolymer as an alternative to the use of conventional polymers. In this sense, the incorporation of fillers or reinforcements coming preferably from other substances of natural origin, can be an alternative to try to improve some mechanical and thermal properties of starch polymers. Thus, Kraft Lignin (KL), can be an excellent filler to be incorporated, since it presents mechanical and thermal properties and reduces the cost and weight of the final compounds. TPS films were prepared by casting using dimethyl sulfoxide (DMSO) as solvent and additives with 2, 4 and 8% KL. Characterization of TPS films and compositions with KL were carried out by Fourier-Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscope (SEM), Thermogravimetric Analysis (TGA), Dynamic Thermomechanical Analysis (DMTA), tensile testing and contact angle. Samples were also analyzed for biodegradation and for the ability to remove contaminants in water, Metil Orange (MO), by Ultraviolet-Visible Spectroscopy (UV–Vis). The FT-IR spectra of the films showed bands typical of functional groups derived from starch and lignin, with the intensity of these bands varying among the samples studied. Micrographs revealed slightly different morphologies among the films, but all showed irregular shapes with structures that appeared as plots. Increasing the percentage of KL led to an increase in contact angle values, showing a more hydrophobic behavior. In the TGA analysis, it was possible to observe a change in the main degradation event of the films for lower temperatures, especially of TPS – 4 and 8% KL compared to the TPS film. Films with KL had the peak of maximum degradation shifted to temperatures below the starch film, where the decrease in intensity of the main peak in the TPS - 4% KL and TPS - 8% KL samples demonstrates that there was less mass loss in the event. There was also in the percentage of residue as the addition of KL was increased The DMTA analyses allowed for the conclusion that presence of KL in TPS film allowed for an increase in its energy storage property, and that the loss modulus followed a decreasing order of storage modulus values to TPS - 8% KL from TPS. For the tensile strength property only TPS - 4% KL has significant improvement, and the elongation at break showed an increase for TPS – 4 and 8% KL compared to TPS. Samples showed a continuous and progressive biodegradation process, being completely biodegraded within 10 days. The monitoring of the ability to remove contaminants from water by UV–Vis, also showed promising results of compounds for this application. The best results were obtained, in most tests, for the TPS- 4% KL films. Polymers and Biopolymers Technology Laboratory (TecPBio) Institute of Science and Technology (ICT) Federal University of São Paulo (UNIFESP) Lignocellulosic Materials Laboratory Science and Technology Center for Sustainability (CCTS) Federal University of São Carlos (UFSCar), João Leme dos Santos, km 110 Science and Technology Institute of Sorocaba (ICTS) São Paulo State University (UNESP), Av. Três de Março, 511 Science and Technology Institute of Sorocaba (ICTS) São Paulo State University (UNESP), Av. Três de Março, 511 CAPES: 001 FAPESP: 2019/15976-0 FAPESP: 2019/19401-1 CNPq: 313989/2018-4

In this work, chitosan/caffeic acid mixtures in the weight ratios of 80/20 and 50/50 were used to obtain thin films enriched with poly(ethylene glycol). It was hypothesized that the presence of caffeic acid indicates the antibacterial properties of the materials (i) and that poly(ethylene glycol) acts as a films modifier (ii). The results showed that by poly(ethylene glycol) addition, the surface free energy as well as mechanical and thermal properties were improved. Moreover, water vapor permeability was observed. All the tested materials showed antioxidant properties in the range of approximately 90%. They also showed antibacterial effectiveness against both Gram-positive and Gram-negative bacteria. The most appropriate material for the application as packaging was composed of chitosan and caffeic acid mixed in a 50/50 weight ratio with 20% PEG addition.

Chitosan microspheres (CMS) by the emulsion-chemical cross-linking method with and without lysozyme immobilization were synthesized and characterized. The technique conditions were adjusted, and spherical particles with approximate diameters of 3.74 ± 1.08 μm and 0. 29 ± 0.029 μm to CMS and chitosan-lysozyme microspheres (C-LMS), respectively, were obtained. The microspheres were characterized by scanning electron microscopy (FESEM), Spectroscopy Fourier Transform Spectroscopy (ATR-FTIR), X-ray diffraction (XRD), and zeta potential. Particle size was identified by laser light scattering (DLS) and the thermal properties by Differential Scanning Calorimetry (DSC) and Thermogravimetry (TGA) were determined. By the lysis of Micrococcus lysodeikticus, the activity of the microspheres was determined, and the results correlated with the amount of lysozyme used in the immobilization process and the enzyme loading efficiency was 67%. Finally, release tests pointed out the amount of enzyme immobilized on the microsphere surface. These results showed that chitosan microspheres could be used as material for lysozyme immobilization by cross-linking technique. The antimicrobial activity was tested by inhibition percent determination, and it evidenced both chitosan microspheres (CMS) and chitosan-lysozyme microspheres (C-LMS) positive antimicrobial activity to Staphylococcus aureus, Enterococcus faecalis and Pseudomonas aeruginosa.

Red grape pomace was used as a source for poly(3-hydroxybutyrate) (PHB) production, which was then subject to a range of purification processes. The different PHB biopolymers were characterized for chemical structure, crystallinity, thermal properties, colour, release of compounds into different food simulants and antioxidant inhibition, and comparisons were made with a commercially available PHB. An increase in purification steps did not have a significant effect on the high thermal stability of the extracted biopolymer, but it decreased the degree of crystallinity and the presence of amino acids and aromatic compounds. With additional purification, the PHB powders also whitened and the number of components released from the biopolymer into food simulants decreased. The released compounds presented antioxidant inhibition, which has not been previously reported in the literature or with commercially available polyhydroxyalkanoates. This is of great interest for food packaging and biomedical industries where the addition of antioxidant additives to improve PHB functional properties may not be necessary and could be avoided. The authors would like to thank the Ministry of Business, Innovation and Employment of New Zealand (MBIE, Biocide Toolbox programme), the Basque Government (KK-2021/00131 and IT1658-22) and PID2021-124294OB-C22 project funded by MCIN/AEI/10.13039/501100011033/FEDER, UE. A.E. thanks the State Research Agency of Spain within the Juan de la Cierva - Incorporation action (IJC2019-039697I).

Made available in DSpace on 2020-12-12T02:46:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-11-15 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) This study evaluated the effect of amylases on the formation, and characteristics of retrograded starches using sweet potato (SPS), cassava (CAS) and high amylose maize (HAS) starches. The starches were gelatinized, hydrolyzed with fungal or maltogenic α-amylase, de-branched and retrograded. The modified starches were then analyzed for digestibility, chain size distribution, relative crystallinity and crystallite size, thermal properties and the proportion of double helices. CAS was the most susceptible and HAS the most resistant to the action of both enzymes. Amylolysis was efficient in forming resistant starch type 3 (RS3) and high levels (> 60%) were found for all starches. RS3 content was highly correlated with the proportion of chains with degrees of polymerization between 13 and 30 for all starches, especially for the root starches, while for HAS, the high amylose content and reduction in the size of amylose chains and very long amylopectin chains also deeply contributed for the RS3 formation. These sizes (DP 13–30) are best suited for the formation of a more crystalline, more perfect, and more strongly bonded structure, composed of larger crystallites, and with a higher concentration of double helices. High correlation coefficients were found between RS3, relative crystallinity, crystallites size, and enthalpy change. UNESP –– São Paulo State University Department of Food Engineering and Technology, Rua Cristovao Colombo, 2265 USP –– University of Sao Paulo Sao Carlos Institute of Chemistry, Avenida Trabalhador São-carlense 400, CEP 13560-590, 780 Embrapa Instrumentation –– Brazilian Agricultural Research Corporation, Rua XV de Novembro 1452, CEP 13560-970, 741 UNESP –– São Paulo State University Department of Chemistry and Environment Science, Rua Cristovao Colombo, 2265 UNESP –– São Paulo State University Department of Food Engineering and Technology, Rua Cristovao Colombo, 2265 UNESP –– São Paulo State University Department of Chemistry and Environment Science, Rua Cristovao Colombo, 2265 FAPESP: 2016/20970-2 FAPESP: 2017/19521-1 CNPq: 307942/2015-5

International audience; The present study was undertaken to establish a distinct relationship between blue crab chitosan (Cs) acetylation degree (AD) and molecular weight (Mw) and its structural features, thermal properties and bioactivity. Therefore, chitosans with different AD were prepared and Cellulase was used to produce Cs derivatives with decreasing Mw. Results clearly display a decrease of the ordered structure of Cs, with the increase of AD and the decrease of Mw. Thermal stability/degradation screening disclose a greater thermal resistance for Cs with lower AD and higher Mw. The anti-adhesive potential of Cs was, additionally, studied, as function of AD and Mw. The effectiveness of Cs in preventing biofilm adhesion was strongly influenced by its AD and Mw, with the lowest inhibition values for higher AD and lower Mw. Interestingly, the effectiveness of Cs in disrupting pre-formed biofilms increased with decreasing Mw. Moreover, Cs derivatives were found to be advantageously efficient in prolonging human blood clotting times, based on data of activated partial thromboplastin time, Quick time and thrombin time assays, typically for the intrinsic coagulation pathway. Accordingly, depending on the predicted application of Cs, either in food, biomedical and pharmaceutical industries, AD and Mw are critical traits to be inevitably reflected on.

Anchote (Coccinia abyssinica) starch films were prepared by a solution casting method with glycerol, 1-ethyl-3-methylimidazolium acetate, sorbitol or triethylene glycol as plasticizers. The effect of these plasticizers and their concentration on film microstructure, thermal, and mechanical properties was investigated. Scanning electron microscopy revealed that regardless of plasticizer type, films possessing higher plasticizer content had more homogeneous morphologies than those with lower plasticizer content. The FTIR spectra of films plasticized with 1-ethyl-3-methylimidazolium acetate had higher intensity peaks at 3150, 1400 and 1000 cm−1 when compared to other film peaks. These data show that 1-ethyl-3-methylimidazolium acetate plasticized films have decreased molecular order which results in less hydrogen bonding. For this reason, films developed from 1-ethyl-3-methylimidazolium acetate were more flexible than the others. The effect of plasticizers on the thermal properties of the anchote starch films was investigated using thermogravimetric analysis (TGA). Films made from 30% (w/w) plasticizer concentration exhibited higher thermal stability for all types of plasticizer. Mechanical testing showed that sorbitol films had the highest tensile strength, approximately 2 times that of the triethylene glycol plasticized film and 3 times that of the film made from 1-ethyl-3-methylimidazolium acetate.

Photocatalytic properties of titanium dioxide (TiO2) have been widely studied. However, its tendency to aggregation in biopolymer-based nanocomposites limits its application for food packaging and has been few studied. The aim of this work was to study the dispersion of TiO2 (0–2 wt%) incorporated in the hydroxypropyl methylcellulose (HPMC-TiO2) and gelatin (gelatin-TiO2) film forming solutions. Particle size and zeta potential of TiO2 nanoparticles were investigated. Nanocomposite films were characterized as to the thickness, moisture content, solubility, color, absorption to the light, relative opacity, morphology, chemical composition, crystallinity, thermal and mechanical properties and water vapor permeability (WVP). TiO2 nanoparticles showed better dispersion in acid medium than water. Moisture content, water solubility and WVP of the gelatin-TiO2 films were influenced by the incorporation of TiO2, while HPMC-TiO2 films were not. The increase of relative opacity of the films as TiO2 was more attenuated for the gelatin-TiO2 films due to lower TiO2 aggregation in gelatin. Morphology, chemical composition, crystallinity and thermal properties of the films evidenced that TiO2 was better dispersed in both matrices at 1 wt%. It was also concluded that TiO2 aggregation generated more biphasic regions in HPMC than generated in gelatin, which caused a microstructural reorganization in the matrices.

The present work aimed at investigating an extraction protocol based on consecutive steps of isoelectric point (pH ~ 4.25) mediated gum swelling and deproteinisation as an alternative method to produce flaxseed gum extracts of enhanced techno-functional characteristics. The osidic and proximate composition, structure conformation, flow behaviour, dynamic rheological and thermal properties of gums isolated from brown and golden flaxseeds were assessed. Gum extraction under near-to-isoelectric point conditions did not impair the extraction yield, residual protein and ash content, whilst it resulted in minor changes in the sugar composition of the flaxseed gum extracts. The deconvolution of the GPC/SEC chromatographs revealed the presence of four major polysaccharidic populations corresponding to arabinoxylans, rhamnogalacturonan–I and two AX-RG-I composite fractions. The latter appeared to minimise the intra- and interchain polymer non-covalent interactions (hydrogen bonding) leading to a better solvation affinity in water and lyotropic solvents. Golden flaxseed gums exerted higher molecular weight (Mw = 1.34–1.15 × 106 Da) and intrinsic viscosities (6.63–5.13 dL g−1) as well as better thickening and viscoelastic performance than the brown flaxseed gum exemplars. Golden flaxseed gums exhibited a better thermal stability compared to the brown flaxseed counterparts and therefore, are suitable for product applications involving severe heat treatments.

Made available in DSpace on 2021-06-25T10:59:44Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-07-31 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The diversification of raw materials in the starch industries is a current strategy. However, the production of native starches does not meet market demand, and it is essential to expand the knowledge about chemical modifications in the same production line for different sources of starch. Phosphate starches are one of the most abundantly produced and widely used chemically modified starches. However, the effects of this modification may vary with the starch source and the reaction conditions. In this study, arrowroot, cassava and sweet potato starches were modified with sodium trimetaphosphate (STMP)/sodium tripolyphosphate (STPP) mixture under same conditions. The reaction time ranged from 7.5 to 120 min. Unmodified and modified starches were analyzed for phosphorus, amylose, morphology, X-ray diffraction pattern, crystallinity, swelling power, solubility, pasting and thermal properties. Phosphorus content linked to the starches increased with the reaction time, which affected the physicochemical properties of the three starches. The changes were more significant in all reaction times for cassava starch, followed by arrowroot. Due to its intrinsic characteristics, longer reaction times were necessary for more significant changes in sweet potato starch. Regardless of the starch source, as the reaction time increased, the average starch granule diameter, swelling power, solubility and peak viscosity increased. There was a decrease in setback in the longer reaction times for cassava and arrowroot starches. The changes in the reaction times allowed obtaining phosphate tuberous starches with different properties which can meet the demands of the food and non-food industries. Center for Tropical Roots and Starches (CERAT) São Paulo State University (UNESP) Department of Food Engineering and Technology São Paulo State University (UNESP) Center for Tropical Roots and Starches (CERAT) São Paulo State University (UNESP) Department of Food Engineering and Technology São Paulo State University (UNESP) FAPESP: 2016/25791-9 CNPq: 302827/2017-0

The ultrafine fibers were produced using a polymeric blend of soy protein isolate (SPI), polyethylene oxide (PEO), and zein at a ratio of 1:1:1 (v/v/v) by electrospinning. The ginger essential oil (GEO) was encapsulated in the ultrafine fibers and the morphology, Fourier-Transform Infrared Spectroscopy (FTIR) analysis, thermal properties and relative crystallinity were evaluated. The antimicrobial activity of ginger essential oil was evaluated against five bacteria (Listeria monocytogenes, Staphylococcus aureus, Escherichia coli 0157:H7, Salmonella typhimurium, and Pseudomonas aeruginosa). Based on the preliminary tests, the concentration of GEO selected to add in the polymer solution was 12% (v/v; GEO/polymer solution). The fiber produced with 12% (v/v) GEO was used for antimicrobial analysis and in situ application (in fresh Minas cheese) against L. monocytogenes by micro-atmosphere. The ultrafine fibers produced, regardless the concentration of the essential oil, presented homogeneous morphology with cylindrical shape without the presence of beads. The application of the active fibers containing 12% GEO showed high potential to be applied in food packaging to reduce microbial contamination.

WOS: 000442057700082 PubMed: 29859279 The objective of this study was to characterize on the chemical, mechanical, electrical and thermal properties of nanofibrillated cellulose based polyvinyl alcohol (PCNF) and silica (SiCNF) films obtained from Pulpzyme HC 2500 and Celluclast 1.5 L enzyme treated kraft-NaBH4 pulps. Morphological alterations were monitored with SEM. Thermal stability, chemical characterization and crystallization were determined using TGA and FT-IR. Young's and storage moduli of the films were determined via a universal testing machine and DTMA. Dielectric properties were evaluated using an impedance analyzer. In the PCNF films, new vibrations and chemical shifts were observed. The crystallinity values of the SiCNF films calculated from the FT-IR were in agreement with the TGA results, revealing that the lowest crystallinity value was in the SiCNF. The higher Young modulus and elongation at break value were obtained in the neat the CNF films while the lowest values were observed in the neat SiCNF films. However, the SiCNF films revealed higher thermo-mechanical property. The PCNF and SiCNF films exhibit more visible dielectric behavior than that of the neat CNF films. Higher thermal stability, thermo-mechanical and mechanical properties were determined in the Pulpzyme HC 2500 enzyme treated films. Hence, this study evidenced that the properties of CNF films having different matrix are influenced by both the enzymes employed. (C) 2018 Elsevier B.V. All rights reserved. TUBITAKTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [COST 1140022]; Istanbul University Research FundIstanbul University [4806, 19515] The authors thank TUBITAK (Project Number: COST 1140022) for support in this research. The authors also thank Istanbul University Research Fund for its financial support in this study (Project Number: 4806 and Project Number: 19515).

The objective of this study was to generate and characterize physically cross-linked aerogels by using germinated and non-germinated wheat starch, with and without the addition of poly (ethylene oxide) (PEO). Aerogels were produced by gelatinization of starch (10% w/v, in distilled water) at 90 °C, followed by multiple freeze/thaw cycles. For the aerogel produced using starch and PEO, a solution of 6% PEO (0.6 g of PEO/10 mL of distilled water) was added to the dispersion. The thermal properties, infrared spectra, relative crystallinity, morphology, water absorption properties, and texture profile of the aerogels were evaluated. After immersion in water for 24 h, the aerogels exhibited high degradation temperature, water absorption capacity, and physical integrity. Aerogels produced using the germinated wheat starch were much more integrated structurally compared to the aerogels produced using the non-germinated wheat starch. Wheat germination did not have any impact on the textural parameters of the aerogels. However, addition of PEO increased the water absorption capacity and reduced the hardness and cohesion of the resulting aerogels. Due to the high water absorption potential, the aerogel produced in this study can serve as an absorbent matrix in food packaging.

Made available in DSpace on 2018-12-11T17:18:04Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-06-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) The unripe banana has been studied as a potential source of starch for use in various applications. Considering the importance of phosphorus in the biosynthesis of the starch and also the interference of this mineral in starch properties, in this study it was evaluated the effect of rates of phosphate fertilizer applied in the cultivation of ‘Maçã’ banana on the characteristics of the starch. Starches extracted from fruits from different treatments were analyzed for morphological characteristics, X-ray diffraction pattern, relative crystallinity, granule size, amylose, resistant starch and phosphorus levels, as well as, for pasting and thermal properties. Results showed that the phosphate fertilization has interference on the characteristics of the banana starch led to increase of phosphorus content and size of the granules, reduction of crystallinity and resistant starch content, decrease of viscosity peak, breakdown, final viscosity, setback, transitions temperatures and enthalpy. These changes caused by phosphate fertilizer conditions can be increase the applications of the ‘Maçã’ banana starch. Center for Tropical Roots and Starches (CERAT) São Paulo State University (UNESP) Department of Horticulture College of Agricultural Sciences (FCA) UNESP Department of Food Engineering and Technology Institute of Biosciences Language and Physical Sciences (IBILCE) UNESP Center for Tropical Roots and Starches (CERAT) São Paulo State University (UNESP) Department of Horticulture College of Agricultural Sciences (FCA) UNESP Department of Food Engineering and Technology Institute of Biosciences Language and Physical Sciences (IBILCE) UNESP CNPq: 303373/2014-8 CNPq: 304571/2013-0

Thermoplastic cassava starch (TPCS) is a promising alternative material to replace the non-biodegradable petroleum based polymer due to its good environmental-friendly aspect i.e. abundant, sustainable, recyclable and biodegradable in nature. However, TPCS have some limitation such as poor mechanical properties. Therefore, in the present study, cogon grass fibre (CGF) were incorporated into TPCS using compression molding. Then the fundamental properties of CFG/TPCS biopolymer composites were carried out in order to evaluate their potential as a biodegradable reinforcement. From the study it was found that, the incorporation of CFG has improved the tensile and flexural properties of the TPCS composites, while the impact strength and elongation were reduced. The thermal properties of the biocomposite were reduced as the cogon grass fibres increase from 0 to 5%. In term of morphological, SEM shows good fibre adhesion between CGF and TPCS. Soil burial test shows that incorporation of CGF into TPCS has slow down the biodegradation process of the composites. Thus, CGF/TPCS biopolymer composites can be classified as composites with great potential as environmental-friendly material that biodegradable and renewable.

The aim of this study was to produce ultrafine fibers from zein incorporated with a complex of eucalyptus essential oil (EEO) and β-cyclodextrin (β-CD) with antimicrobial properties by electrospinning technique. The EEO was characterized by chemical composition and antimicrobial tests against three Gram positive and four Gram negative bacteria. The inclusion complex (IC) was prepared with β-CD and EEO by co-precipitation technique and added at different concentrations in zein polymer solution using aqueous ethanol as solvent. The morphology, thermal properties, functional groups, and antimicrobial activity against L. monocytogenes and S. aureus of the ultrafine fibers were evaluated. The composite membranes containing 24% IC exhibited a greater reduction of growth as compared to the fibers without addition of IC. For L. monocytogenes the growth reduction was 28.5% and for S. aureus it was 24.3%. The electrospun IC-β-CD/EEO composite membranes are promising for use in antimicrobial applications, such as food packaging.

In this study, microcrystalline cellulose (MCC) was extracted from roselle fiber through acid hydrolysis treatment and its properties were compared with those of commercially available MCC. The physicochemical and morphological characteristics, elemental composition, size distribution, crystallinity and thermal properties of the obtained MCC were analyzed in this work. Fourier transform infrared spectroscopy (FTIR) analysis provided clear evidence that the characteristic peak of lignin was absent in the spectrum of the MCC prepared from roselle fiber. Rough surface and slight aggregation of MCC were observed by scanning electron microscopy (SEM). Energy dispersive X-ray (EDX) analysis showed that pure MCC with small quantities of residues and impurities was obtained, with a similar elemental composition to that of commercial MCC. A mean diameter of approximately 44.28μm was measured for MCC by using a particle size analyzer (PSA). X-ray diffraction (XRD) showed the crystallinity increased from 63% in roselle pulp to 78% in roselle MCC, the latter having a slightly higher crystallinity than that of commercial MCC (74%). TGA and DSC results indicated that the roselle MCC had better thermal stability than the roselle pulp, whereas it had poorer thermal stability in comparison with commercial MCC. Thus, the isolated MCC from roselle fibers will be going to use as reinforcing element in green composites and may be a precursor for future roselle derived nanocellulose, and thus a promising subject in nanocomposite research.

A hybrid composite was prepared from cassava bagasse (CB) and sugar palm fiber (SPF) using casting technique with cassava starch (CS) as matrix and fructose as a plasticizer. Different loadings of SPF (2, 4, 6 and 8% w/w of dry starch) were added to the CS/CB composite film containing 6% CB. The addition of SPF significantly influenced the physical properties. It increased the thickness while decreasing the density, water content, water solubility and water absorption. However, no significant effect was noticed on the thermal properties of the hybrid composite film. The incorporation of SPF increased the relative crystallinity up to 47%, compared to 32% of the CS film. SEM micrographs indicated that the filler was incorporated in the matrix. The film with a higher concentration of SPF (CS-CB/SPF8) showed a more heterogeneous surface. It could be concluded that the incorporation of SPF led to changes in cassava starch film properties, potentially affecting the film performances.

Galactomannan extracted from Cassia grandis seeds was used for the production of films containing different concentrations of the bioactive compounds lactoferrin (LF), bioactive peptides (BAPs), and phytosterols. SEM, FTIR, mechanical and thermal properties, colour, moisture content (MC), solubility, water vapour permeability (WVP), and contact angle (CA) were performed evaluating the effect of increasing concentrations of bioactive compounds on the films physicochemical properties. The immobilization of bioactive compounds leads to films with roughness on their surface, as observed by SEM. The thermal events demonstrated that bioactive compounds avoided the establishment of more hydrogen bonds when compared to galactomannan control film; this behaviour was also confirmed by FTIR. All the studied films had a strong whiteness tendency as well as a yellowish appearance. The addition of Lf reduced MC and solubility values and leads to an increase of WVP and CA values, while the addition of BAPs and phytosterols did not changed the film solubility. The mechanical properties were affected by the addition of bioactive compounds, which improved the stiffness of the films. Galactomannan-based films from C. grandis showed to be a promising structure for the immobilization of biomolecules, pointing at a significant number of possible applications in food and pharmaceutical industries., This study was supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) and the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI-01-0145-FEDER-006684) and under the scope of the Project RECI/BBB-EBI/0179/2012 (FCOMP- 01-0124-FEDER-027462). Priscilla B.S. Albuquerque is recipient of a scholarship from CAPES. Maria G. Carneiro-da-Cunha express her gratitude to the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for research grants and fellowship. The authors acknowledge the University of Minho and Dmitri Petrovykh from International Iberian Nanotechnology Laboratory for analytical support and CNPq and CAPES for financial support.

In the present study, poly(vinyl alcohol) (PVA) - Acacia lignin (PL) nanofiber mats loaded with silver nanoparticles were prepared and characterized. In-situ synthesis of silver nanoparticles was accomplished using alkali lignin extracted from Acacia wood as a reducing agent. Ultrafine nanofiber mats of PL incorporated with silver nanoparticles were fabricated using the electrospinning technique. The fiber morphology of the resultant nanofiber was characterized using scanning electron microscopy. The average diameter of the nanofiber was in the range of 100 to 300 nm. The existence of silver nanoparticles was confirmed by X-ray diffraction analysis. The influence of silver nanoparticles on the polymer structure was investigated by mechanical and thermal properties analysis. The antimicrobial activity of the PL nanofibers containing silver nanoparticles was tested against Bacillus circulans (MTCC 7906) and Escherichia coli (MTCC 739) and showed significant results against both microorganisms. The results revealed that PL nanofiber containing silver nanoparticles may have potential applications as membrane filtration, antimicrobial fabrics and wound dressing material.

Lignin-based nanofibers were produced via centrifugal spinning from lignin-thermoplastic polyurethane polymer blends. The most suitable process parameters were chosen by optimization of the rotational speed, nozzle diameter and spinneret-to-collector distance using different blend ratios of the two polymers at different total polymer concentrations. The basic characteristics of polymer solutions were enlightened by their viscosity and surface tension. The morphology of the fibers produced was characterized by SEM, while their thermal properties by DSC and TG analysis. Multiply regression was used to determine the parameters that have higher impact on the fiber diameter. It was possible to obtain thermally stable lignin/polyurethane nanofibers with diameters below 500 nm. From the aspect of spinnability, 1:1 lignin/TPU contents were shown to be more feasible. On the other side, the most suitable processing parameters were found to be angular velocity of 8500 rpm for nozzles of 0.5 mm diameter and working distance of 30 cm. (C) 2018 Elsevier B.V. All rights reserved.

Surgical adhesives have been used for several applications, including haemostasis, sealing air leakages and tissue adhesion. The aim of this work was to develop a biodegradable urethane-based bioadhesive containing free isocyanate groups. This material presents the advantage of being biodegradable, biocompatible and having the capacity of reacting with amino groups present in the biological molecules. A urethane based on castor oil (CO) was synthesized by reaction of the molecule with isophorone diisocyanate (IPD). The characterization of the material was accomplished by different techniques: ATR-FT-IR (attenuated transmittance reflection-Fourier transform infrared), swelling capacity determination, evaluation of the moisture curing kinetics, reaction with aminated substrates and determination of surface energy by contact angle measurement. The study of the urethane thermal properties was performed by DMTA (dynamical mechanical thermal analysis) and TGA (thermogravimetric analysis). The haemocompatibility of the urethane was also evaluated by thrombosis and haemolysis tests.

11 p.-7 fig.-4 tab., Polymeric hydrogels from bacterial cellulose (BC) have been widely used for the development of wound dressings due to its water holding capacity, its high tensile strength and flexibility, its permeability to gases and liquids, but lacks antibacterial activity. In this work, we have developed novel antimicrobial hydrogels composed of BC and the antimicrobial poly(3-hydroxy-acetylthioalkanoate-co-3-hydroxyalkanoate) (PHACOS). Hydrogels based on different PHACOS contents (20 and 50 wt%) were generated and analysed through different techniques (IR, DSC, TGA, rheology, SEM and EDX) and their bactericidal activity was studied against Staphylococcus aureus. PHACOS20 (BC 80%-PHACOS 20%) hydrogel shows mechanical and thermal properties in the range of human skin and anti-staphylococcal activity (kills 1.8 logs) demonstrating a huge potential for wound healing applications. Furthermore, the cytotoxicity assay using fibroblast cells showed that it keeps cell viability over 85% in all the cases after seven days., Authors thank financial support to thank the Spanish Ministry of Science,Innovation and Universities [MAT2017-84277-R and Bio2017-8344-8-R], the European Union’s Horizon 2020 Research and Innovation Programme [grant agreement no 870294 (Mix-Up)] and the Community of Madrid [P2018/NMT4389] for the financial support of this project.