Percorrer por autor "Ruiz-Matute, Ana I."
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- Improving Properties of a Novel β-Galactosidase from Lactobacillus plantarum by Covalent ImmobilizationPublication . Benavente, Rocio; Pessela, Benevides C.; Curiel, Jose Antonio; de las Rivas, Blanca; Muñoz, Rosario; Guisán, Jose Manuel; Mancheño, Jose M.; Cardelle-Cobas, Alejandra; Ruiz-Matute, Ana I.; Corzo, NievesA novel -galactosidase from Lactobacillus plantarum (LPG) was over-expressed in E. coli and purified via a single chromatographic step by using lowly activated IMAC (immobilized metal for affinity chromatography) supports. The pure enzyme exhibited a high hydrolytic activity of 491 IU/mL towards o-nitrophenyl -d-galactopyranoside. This value was conserved in the presence of different divalent cations and was quite resistant to the inhibition effects of different carbohydrates. The pure multimeric enzyme was stabilized by multipoint and multisubunit covalent attachment on glyoxyl-agarose. The glyoxyl-LPG immobilized preparation was over 20-fold more stable than the soluble enzyme or the one-point CNBr-LPG immobilized preparation at 50 degrees C. This -galactosidase was successfully used in the hydrolysis of lactose and lactulose and formation of different oligosaccharides was detected. High production of galacto-oligosaccharides (35%) and oligosaccharides derived from lactulose (30%) was found and, for the first time, a new oligosaccharide derived from lactulose, tentatively identified as 3'-galactosyl lactulose, has been described.
- Study of Functional properties of chitosan-lactose derivatives obtained by Maillard reactionPublication . Ruiz-Matute, Ana I.; García-Bermejo, Ana B.; Cardelle-Cobas, Alejandra; Olano, Agusín; Corzo, Nieves
- Synthesis, optimization and structural characterization of a chitosan-glucose derivative obtained by the Maillard reactionPublication . Gullón, Beatriz; Montenegro, María I.; Ruiz-Matute, Ana I.; Cardelle-Cobas, Alejandra; Corzo, Nieves; Pintado, Manuela E.Chitosan (Chit) was submitted to the Maillard reaction (MR) by co-heating a solution with glucose (Glc). Different reaction conditions as temperature (40, 60 and 80 °C), Glc concentration (0.5%, 1%, and 2%, w/v), and reaction time (72, 52 and 24h) were evaluated. Assessment of the reaction extent was monitored by measuring changes in UV absorbance, browning and fluorescence. Under the best conditions, 2% (w/v) of Chit, 2% (w/v) of Glc at 60°C and 32 h of reaction time, a chitosan-glucose (Chit-Glc) derivative was purified and submitted to structural characterization to confirm its formation. Analysis of its molecular weight (MW) and the degree of substitution (DS) was carried out by HPLC-Size Exclusion Chromatography (SEC) and a colloid titration method, respectively. FT-IR and (1)H NMR were also used to analyze the functional groups and evaluate the introduction of Glc into the Chit molecule. According to our objectives, the results obtained in this work allowed to better understand the key parameters influencing the MR with Chit as well as to confirm the successful introduction of Glc into the Chit molecule obtaining a Chit-Glc derivative with a DS of 64.76 ± 4.40% and a MW of 210.37 kDa.