Modification of Pea Starch and Dextrin Polymers with Isocyanate Functional Groups

Pea starch and dextrin polymers were modified through the unequal reactivity of isocyanate groups in isophorone diisocyanate (IPDI) monomer. The presence of both urethane and isocyanate functionalities in starch and dextrin after modification were confirmed by Fourier transform infrared spectroscopy (FTIR) and C-13 nuclear magnetic resonance (C-13 NMR). The degree of substitution (DS) was calculated using elemental analysis data and showed higher DS values in modified dextrin than modified starch. The onsets of thermal degradation and temperatures at maximum mass losses were improved after modification of both starch and dextrin polymers compared to unmodified ones. Glass transition temperatures (T-g) of modified starch and dextrin were lower than unmodified control ones, and this was more pronounced in modified dextrin at a high molar ratio. Dynamic water vapor sorption of starch and dextrin polymers indicated a slight reduction in moisture sorption of modified starch, but considerably lower moisture sorption in modified dextrin as compared to that of unmodified ones.Reza Hosseinpourpia and Stergios Adamopoulos thank VINNOVA, Swedish Governmental Agency for Innovation Systems (VINNMER Marie Curie Incoming project, grant No. 2015-04825). Arantzazu Santamaria-Echart and Arantxa Eceiza wish to acknowledge the financial support from the Basque Government in the frame of Grupos Consolidados (IT-776-13) and SGIker from the University of the Basque Country for their Technical support

3D printing of customized all-starch tablets with combined release kinetics

[EN] Starch-based tablets with tailored releases were prepared by 3D printing using a hydrophobic drug. The importance of the origin of the excipient in the inks and tablets was analyzed. Besides, the effect of the geometry of the tablet on the drug release profile was also evaluated. The rheological properties of the inks was influenced by the botanic origin of the starch. Consequently, tablets presented different microporous structure and particular compression and swelling behaviors. Normal maize starch showed a non-well-defined porous morphology, not being able to form a stable structure whereas, waxy maize and potato starches exhibited a well-defined porous structure and were both able to maintain their integrity after long time immersion. Finally, tablets combining different starches and geometries were printed tailoring the drug release from 10 min to 6 h and designing two-steps profiles. The applicability of the developed 3D printed drug release systems in personalized therapies was demonstrated.Financial support from the University of the Basque Country (UPV/EHU) (GIU18/216 Research Group), from the Basque Government in the frame of Elkartek KK-2020/00053 and PIBA2020-1-0041 and from Spanish Ministry of Science and Innovation and Spanish State Research Agency (MCIN/AEI/10.13039/501100011033) in the frame of PID2019-105090RB-I00 project, are gratefully acknowledged. Moreover, we are grateful to the Macrobehavior-Mesostructure-Nanotechnology SGIker unit of the UPV/EHU. K. González thanks the University of the Basque Country for the grant “Contratación de doctores recientes hasta su integración en programas de formación postdoctoral en la UPV/EHU «DOKBERRI» 2020-I” (DOCREC20/07)

Superabsorbent bacterial cellulose spheres biosynthesized from winery by-products as natural carriers for fertilizers

[EN]Soil contamination, sustainable management of water resources and controlled release of agrochemicals are the main challenges of modern agriculture. In this work, the synthesis of sphere-like bacterial cellulose (BC) using agitated culture conditions and Komagateibacter medellinensis bacterial strain ID13488 was optimized and characterized from grape pomace (GP). First, a comparative study was carried out between agitated and static cultures using different nitrogen sources and applying alternative GP treatments. Agitation of the cultures resulted in higher BC production yield compared to static culture conditions. Additionally, Water holding capacity (WHC) assays evidenced the superabsorbent nature of the BC biopolymer, being positively influenced by the spherical shape as it was observed an increase of 60% in contrast to the results obtained for the BC membranes under static culture conditions. Moreover, it was found that sphere-like BCs were capable of retaining urea up to 375% of their dry weight, rapidly releasing the fertilizer in the presence of water. According to our findings, sphere-like BCs represent suitable systems with great potential for actual agricultural hazards and grape pomace valorisation.Financial support from the University of the Basque Country (UPV/EHU) (GIU18/216 Research Group), from the Basque Government in the frame of Elkartek KK-2020/00053 and PIBA2020-1-0041 and from Spanish Ministry of Science, Innovation and Universities and European Union (MICINN/EU/FEDER) in the frame of MAT2016-76294-R and PID2019-105090RB-I00 projects, are gratefully acknowledged. The authors also thank the technical support and personnel provided by the Servicio de Lipidómica y Metabolomica of the SGIKER (UPV/EHU,MICINN, GV/E.G., ESF) and the Phytotron Service of UPV/EHU. Moreover, are grateful to the Macrobehavior-Mesostructure-Nanotechnology SGIker unit of the UPV/EHU. Díaz-Ramírez J wishes to acknowledge the Department of Agriculture, Fisheries and Food policy of the Basque Government for the PhD grant (00020-PIT2019-22)

Superabsorbent bacterial cellulose spheres biosynthesized from winery by-products as natural carriers for fertilizers

[EN]Soil contamination, sustainable management of water resources and controlled release of agrochemicals are the main challenges of modern agriculture. In this work, the synthesis of sphere-like bacterial cellulose (BC) using agitated culture conditions and Komagateibacter medellinensis bacterial strain ID13488 was optimized and characterized from grape pomace (GP). First, a comparative study was carried out between agitated and static cultures using different nitrogen sources and applying alternative GP treatments. Agitation of the cultures resulted in higher BC production yield compared to static culture conditions. Additionally, Water holding capacity (WHC) assays evidenced the superabsorbent nature of the BC biopolymer, being positively influenced by the spherical shape as it was observed an increase of 60% in contrast to the results obtained for the BC membranes under static culture conditions. Moreover, it was found that sphere-like BCs were capable of retaining urea up to 375% of their dry weight, rapidly releasing the fertilizer in the presence of water. According to our findings, sphere-like BCs represent suitable systems with great potential for actual agricultural hazards and grape pomace valorisation.Financial support from the University of the Basque Country (UPV/EHU) (GIU18/216 Research Group), from the Basque Government in the frame of Elkartek KK-2020/00053 and PIBA2020-1-0041 and from Spanish Ministry of Science, Innovation and Universities and European Union (MICINN/EU/FEDER) in the frame of MAT2016-76294-R and PID2019-105090RB-I00 projects, are gratefully acknowledged. The authors also thank the technical support and personnel provided by the Servicio de Lipidómica y Metabolomica of the SGIKER (UPV/EHU,MICINN, GV/E.G., ESF) and the Phytotron Service of UPV/EHU. Moreover, are grateful to the Macrobehavior-Mesostructure-Nanotechnology SGIker unit of the UPV/EHU. Díaz-Ramírez J wishes to acknowledge the Department of Agriculture, Fisheries and Food policy of the Basque Government for the PhD grant (00020-PIT2019-22)

Design of a Waterborne Polyurethane-Urea Ink for Direct Ink Writing 3D Printing

In this work, polycaprolactone–polyethylene glycol (PCL–PEG) based waterborne polyurethane–urea (WBPUU) inks have been developed for an extrusion-based 3D printing technology. The WBPUU, synthesized from an optimized ratio of hydrophobic polycaprolactone diol and hydrophilic polyethylene glycol (0.2:0.8) in the soft segment, is able to form a physical gel at low solid contents. WBPUU inks with different solid contents have been synthesized. The rheology of the prepared systems was studied and the WBPUUs were subsequently used in the printing of different pieces to demonstrate the relationship between their rheological properties and their printing viability, establishing an optimal window of compositions for the developed WBPUU based inks. The results showed that the increase in solid content results in more structured inks, presenting a higher storage modulus as well as lower tan δ values, allowing for the improvement of the ink’s shape fidelity. However, an increase in solid content also leads to an increase in the yield point and viscosity, leading to printability limitations. From among all printable systems, the WBPUU with a solid content of 32 wt% is proposed to be the more suitable ink for a successful printing performance, presenting both adequate printability and good shape fidelity, which leads to the realization of a recognizable and accurate 3D construct and an understanding of its relationship with rheological parameters.Financial support from the University of the Basque Country (UPV/EHU) (GIU18-216), Spanish Ministry of Economy and Competitiveness (MINECO) (MAT2016-76294R and PID2019-105090RB-I00) and the Basque Government (KK-2019/00048) are gratefully acknowledged. Julen Vadillo wishes to acknowledge both the University of Pau and Pays de l’Adour and the UPV/EHU for his PhD grant

Integral Valorization of Grape Pomace for Antioxidant Pickering Emulsions

Full harnessing of grape pomace (GP) agricultural waste for the preparation of antioxidant Pickering emulsions is presented herein. Bacterial cellulose (BC) and polyphenolic extract (GPPE) were both prepared from GP. Rod-like BC nanocrystals up to 1.5 µm in length and 5–30 nm in width were obtained through enzymatic hydrolysis (EH). The GPPE obtained through ultrasound-assisted hydroalcoholic solvent extraction presented excellent antioxidant properties assessed using DPPH, ABTS and TPC assays. The BCNC-GPPE complex formation improved the colloidal stability of BCNC aqueous dispersions by decreasing the Z potential value up to −35 mV and prolonged the antioxidant half-life of GPPE up to 2.5 times. The antioxidant activity of the complex was demonstrated by the decrease in conjugate diene (CD) formation in olive oil-in-water emulsions, whereas the measured emulsification ratio (ER) and droplet mean size of hexadecane-in-water emulsions confirmed the physical stability improvement in all cases. The synergistic effect between nanocellulose and GPPE resulted in promising novel emulsions with prolonged physical and oxidative stability.Financial support from the Basque Government as part of the Grupos Consolidados (IT1690-22) and PIBA2020-1-0041 and from the Spanish Ministry of Science and Innovation and Spanish State Research Agency (MCIN/AEI/10.13039/501100011033) as part of the PID2019-105090RB-I00 project is gratefully acknowledged. Moreover, the authors also thank the technical support and personnel from the Macrobehavior-Mesostructure-Nanotechnology unit, Servicio de Lipidómica y Metabolomica and the Central Analysis Service of Bizkaia of SGIker (UPV/EHU, MICINN, GV/E.G., ESF). J. Díaz-Ramírez wishes to acknowledge the Department of Agriculture, Fisheries and Food policy of the Basque Government for his PhD grant (00020-PIT2019-22)

Influence of Process Parameters in Graphene Oxide Obtention on the Properties of Mechanically Strong Alginate Nanocomposites

Sodium alginate, a biopolymer extracted from brown algae, has shown great potential for many applications, mainly due to its remarkable biocompatibility and biodegradability. To broaden its fields of applications and improve material characteristics, the use of nanoreinforcements to prepare nanocomposites with enhanced properties, such as carbonaceous structures which could improve thermal and mechanical behavior and confer new functionalities, is being studied. In this work, graphene oxide was obtained from graphite by using modified Hummers’ method and exfoliation was assisted by sonication and centrifugation, and it was later used to prepare sodium alginate/graphene oxide nanocomposites. The effect that different variables, during preparation of graphene oxide, have on the final properties has been studied. Longer oxidation times showed higher degrees of oxidation and thus larger amount of oxygen-containing groups in the structure, whereas longer sonication times and higher centrifugation rates showed more exfoliated graphene sheets with lower sizes. The addition of graphene oxide to a biopolymeric matrix was also studied, considering the effect of processing and content of reinforcement on the material. Materials with reinforcement size-dependent properties were observed, showing nanocomposites with large flake sizes, better thermal stability, and more enhanced mechanical properties, reaching an improvement of 65.3% and 83.3% for tensile strength and Young’s modulus, respectively, for a composite containing 8 wt % of graphene oxide.This research was funded by Spanish Ministry of Science, Innovation and Universities in the frame of MAT2016-76294-R project, the Basque Government for PIBA 2019-44 project and the Gipuzkoa Council in the frame of Programa de Red Gipuzkoana de Ciencia, Tecnología e Innovación 2019