Conjugados funcionales proteína-quitosano: influencia de las características del quitosano

Trabajo presentado al V Simposio Iberoámericano de Quitina celebrado en Santiago (Chile) del 6 al 9 de junio de 2010 y organizado por la Sociedad Iberoámericano de Quitina.Ministerio de Innovación y Ciencia (Proyecto MAT2004-03982) y Beca FPU concedida a la doctoranda M. Mengíbar).Peer reviewe

Films of chitosan and chitosan-oligosaccharide neutralized and thermally treated: Effects on its antibacterial and other activities

The present study focuses on the effects of heat and neutralization treatments on solubility, water vapour permeability and antimicrobial activity of chitosan (Ch) and chitosan/chitooligosaccharide (ChO)-based films. ChO films showed stronger antimicrobial activity against Escherichia coli, Bacillus cereus, Staphylococcus aureus, Serratia liquefaciens and Lactobacillus plantarum than Ch films, indicating that this effect is attributed to the presence of chitooligosaccharides (COS) in the films. Heat and neutralization treatments decreased significantly the solubility of chitosan films and gave rise to a sharp loss in their antimicrobial activity. The incorporation of COS in chitosan films increased the inhibitory effect against the studied microorganisms without affecting significantly the water vapour permeability of the films. Thus, it is possible to get a more insoluble chitosan film with high antimicrobial activity by means of incorporation of COS combined with heat or neutralization treatments.MINECO, project (MAT2010-21621-C02-01

Use of soluble chitosans in Maillard reaction products with β-lactoglobulin. Emulsifying and antioxidant properties

The reaction of commercially available soluble chitosans of equal acetylation degree (11–12%) and differing in their molecular weight (56–1.3 kDa) and β-lactoglobulin by Maillard reaction has been conducted in order to evaluate the resulting products and their functional properties. The characterization of the reaction products was performed by measurement of z-potential interactions, solubility, size exclusion chromatography, electrophoretic pattern, and absorbance and fluorescence spectroscopic compounds formation. Higher molecular weight chitosans (39 and 56 kDa) showed a slow progression and a gelled insoluble material appeared. In filtered products, emulsifying properties of the conjugates were improved with regard to those of the unreacted protein. Conjugates formed with the enzymatically depolymerized chitosan (1.3 kDa) displayed a sharp formation of advanced and final products of Maillard reaction. Products with all three chitosans gave rise to antioxidant activity superior to the protein after 2 days of reaction (2 and 3 times in ferric reducing power for 39 and 56 kDa chitosans, and 7 times for the 1.3 kDa chitosan, respectively), and the values correlated well with the spectroscopic and fluorescent compounds from the Maillard reaction. The results are useful with a view to selecting chitosans for development of new ingredients with tailored functional properties.This work was partially funded through Project MAT2010-21621-C02-01 and MAT2013-46692-C2-1-R of the Spanish Ministry of Science. M. Mengíbar wants to thank the Ministry of Science (Spain) for a FPU grant.Peer Reviewe

Chito-oligosaccharides (COS) functionality: Antimicrobial activity and antioxidant capacity in vitro

Trabajo presentado al 10th International Conference of the European Chitin Society celebrado en San Petersburgo (Rusia) del 20 al 24 de mayo de 2011.M. Mengíbar wants to thank her FPU grant from Ministry of Innovation and Science (Spain). This research was supported by the Projects MAT2009-058791, MAT2010-21621-C02-01 from Ministry of Innovation and Science (Spain) and S2009/ENE-1660 (Fondos Feder) de la Comunidad Autónoma de Madrid (Spain).Peer Reviewe

Poly-(styrene sulphonic acid): An acid catalyst from polystyrene waste for reactions of interest in biomass valorization

This article reports on the use of poly-(styrene sulphonic acid) (PSSA) prepared by sulphonation of polystryrene waste as catalyst in reactions demanding acid sites. Two different waste derived catalysts (waste to catalyst, WTC) were studied: soluble PSSA (WTC-PSSA) and solid SiO2-PSSA nanocomposite (WTC-SiO2-PSSA). The catalytic properties of these waste derived acid catalysts have been explored in three different reactions of interest in biomass valorization: biodiesel synthesis, xylose dehydration to furfural and furfural oxidation to maleic and succinic acids. The results show that both soluble and nanocomposite WTC catalysts present promising catalytic properties. The WTC-PSSA requires ultrafiltration for reutilization whereas the WTC-SiO2-PSSA can be separated from the reaction mixtures by more usual techniques (centrifugation or conventional filtration). Further research is required for improving the hydrothermal stability of WTC-SiO2-PSSA in order to substantially reduce the leaching of polymer that takes place during the catalytic runs.This work was funded by the Spanish Ministry of Economy and Competitiveness (Project CTQ2012-38204-C03-01, CARBIOCAT) and the Autonomous Government of Madrid (S2009/ENE-1660, CARDENER-CM partly funded by FSE funds).Peer Reviewe

Enzymatic production of fully deacetylated chitooligosaccharides and their neuroprotective and anti-inflammatory properties

Published online: 03 Mar 2017.Among several commercial enzymes screened for chitosanolytic activity, Neutrase 0.8L (a protease from Bacillus amyloliquefaciens) was selected in order to obtain a product enriched in deacetylated chitooligosaccharides (COS). The hydrolysis of different chitosans with this enzyme was followed by size exclusion chromatography (SEC-ELSD), mass spectrometry (ESI-Q-TOF), and high-performance anion-exchange chromatography with pulsed amperometric detection (HPAEC-PAD). Neutrase 0.8L converted 10 g/L of various chitosans into mostly deacetylated oligosaccharides, yielding approximately 2.5 g/L of chitobiose, 4.5 g/L of chitotriose, and 3 g/L of chitotetraose. We found out that the neutral protease was not responsible for the chitosanolytic activity in the extract, while it could participate in the deacetylating process. The synthesized COS were tested in vitro for their neuroprotective (toward human SH-S5Y5 neurons) and anti-inflammatory (in RAW macrophages) activities, and compared with other functional ingredients, namely fructooligosaccharides.This work was supported by grants from the Spanish Ministry of Economy and Competitiveness (BIO2013-48779- C4-1/-4 and BIO2016-76601-C3-1-R/2-R) and Junta de Andalucía (FQM-7316), by an institutional grant from the Fundación Ramón Areces to the Centro de Biología Molecular Severo Ochoa, and by the European Union’s Horizon 2020 Research and Innovation Program [Blue Growth: Unlocking the potential of Seas and Oceans] under grant agreement no. 634486 (INMARE). P. S-M. thanks the Spanish Ministry of Education for FPU Grant.Peer reviewe