Curcumin antifungal and antioxidant activities are increased in the presence of ascorbic acid

The objective of this study was to evaluate the antifungal and antioxidant activities of curcumin, ascorbic acid and the mixture of these two compounds. For the antifungal assay, the minimum inhibitory concentrations (MIC) were determined using Candida strains (ATCC and clinical isolates). Curcumin alone inhibited growth of Candida albicans yeast cells, whereas ascorbic acid did not present effects. However, when the mixture of ascorbic acid and curcumin was assayed to determine the association of the two compounds, the curcumin MIC decreased 5- to 10-fold. In the antioxidant assays, the sum of the alone activities of curcumin and ascorbic acid were lower than the activity of the two-compound mixture. This study highlights the importance of the association between two common antioxidants in foods, to improve the antifungal and antioxidant activities of curcumin (in vitro), and can be applied to Candida spp. infection and diseases associated with oxidative stress.     

A state space approach to the tangential interpolation problem with bounded real matrices

This paper presents a global solution of the tangential interpolation problem via state space concepts. the solution is obtained in two steps. the first step consists of factorization of the Nevanlinna-Pick matrix and calculating the state space vectors of a passive n-port network N. In the second step, using the state space vectors and the interpolation data, a passive minimal state space realization of N is derived from which the desired interpolating bounded real matrix is obtained. the presented approach involves only standard algebraic matrix procedures and provides the constructive algorithm for the interpolating matrix.     

Inulinase Production by Agro-Industrial Residues: Optimization of Pretreatment of Substrates and Production Medium

In this work, production of inulinase was studied. Media formulation was optimized by experimental design and response surface techniques, as well as the pretreatment of the agro-industry residues used in the formulation of fermentation medium. Two agro-industry residues were investigated: sugarcane molasses (SCM) and corn steep liquor (CSL). Pretreatment with sulfuric acid was the most effective for clarification of SCM (pH 5.0, 24 h of resting time and final pH 4.0). Clarification of CSL was accomplished with phosphoric acid (pH 3.0, 24 h of resting time and final pH 5.5). A color reduction of approximately 70% was achieved for both substrates. The highest production of inulinase was obtained in a medium containing 100 g l⁻¹ of pretreated SCM, 100 g l⁻¹ of pretreated CSL and 6 g l⁻¹ of Prodex Lac (yeast hydrolysate), yielding 1,139 U ml⁻¹.     

Thermal hystersis and quadrupole interactions in ferroelectric transitions.

It is shown that a selfconsistent calculation of the maximum amount of thermal hystersis accompanying discountinous ferroelectric transtion can be made if one takes into account the quadrupolar contribution to the effective ferroelectric field. Comparison of calculated and observed thermal hystersis in sereral ferroelectrics belonging to different families shows fair agreement.     

Magnitude of electrogyration effect in crystals

Electrogyration Miller's delta Δ_g is checked for more than 50 crystals. The corelation between Δ_g and other quantites is discussed, similar relation for quadratic electrogyration is introduced.     

Enzymatic synthesis of fructooligosaccharides by inulinases from Aspergillus niger and Kluyveromyces marxianus NRRL Y-7571 in aqueous–organic medium

This work is focused on the synthesis of the fructooligosaccharides (FOS) from sucrose and inulin, using free, immobilized and pre-treated immobilized inulinase from Kluyveromyces marxianus NRRL Y 7571 and Aspergillus niger in an aqueous–organic system. Initially, the influence of pre-treatment using four different gases, propane, n-butane, CO₂ and liquefied petroleum gas (LPG), was investigated towards FOS production and best results were found when both enzymes were previously treated with LPG. The best reaction yields were obtained when the immobilized enzymes were treated with LPG. Considering FOS synthesis using the enzyme from A. niger, yields of 26.62% of GF2 (kestose), 30.62% of GF3 (nystose) and 8.47% of GF4 (fructosyl nystose) were achieved using sucrose as substrate. Using inulinases from K. marxianus NRRL Y 7571, 11.89% of GF2 and 20.83% of GF3 were obtained, using inulin as substrate. However, promising results were achieved using the free form of inulinase from A. niger (77.19% of GF2; 14.03% of GF3 and 0.07% of GF4) using inulin as substrate.     

Fructooligosacharides production in aqueous medium with inulinase from Aspergillus niger and Kluyveromyces marxianus NRRL Y-7571 immobilized and treated in pressurized CO2

This work investigated the influence of compressed CO₂ treatment on the enzymatic activity of immobilized inulinases, and the production of fructooligosacharides in aqueous medium using these enzymes. The effects of system pressure, exposure time and depressurization rate on the enzymatic activity were evaluated through central composite designs (CCD) 2³. Inulinase from Kluyveromyces marxianus NRRL Y-7571 presented an increase of 104% in the residual activity using CO₂ at 275 bar submitted to 6 h treatment, at a depressurization rate of 10 kg m^?3 min^?1. For Aspergillus niger commercial inulinase, a decrease in enzyme activity was observed (residual activity of 39%) using CO₂ treatment at 75 bar for 6 h exposure at the highest depressurization rate (200 kg m^?3 min^?1). Enzymatic activities changed significantly depending on the enzyme source and the experimental treatment conditions investigated. The values of FOS obtained using inulinases from A. niger were 30.64% of GF2; 13.90% of GF3 and 2.88% of GF4 in the medium containing inulin as substrate. Results demonstrate that the use of compressed CO₂ might be of technological importance as a preceding, preparation step, to improve enzyme activity, hence helping the development of new biotransformation processes.     

Evaluation of enzymatic activity of commercial inulinase from Aspergillus niger immobilized in polyurethane foam

The objective of this work was to evaluate the stability of the activity of commercial inulinase from Aspergillus niger immobilized in polyurethane foam. The activity of the enzyme was measured in the hydrolysis reaction of both sucrose and inulin at 50 °C and pH 5.5. The enzyme reuse was evaluated during 59 days and 29 reuse cycles. The inulinase immobilized in polyurethane kept 49.7% and 49.4% of its initial activity during 1008 h and 24 reuse cycles for sucrose and inulin, respectively. In this work, enzyme immobilization was accomplished together with the formation of the polyurethane foam, which is an interesting characteristic, differing from several works found in the literature. Taking into account the promising results obtained, the low cost of the immobilization support employed and the whole technique developed, this work may comprise an innovative contribution.     

Liquefied petroleum gas as solvent medium for the treatment of immobilized inulinases

BACKGROUND: The main goal of this work is to assess the influence of pressurized liquefied petroleum gas (LPG) treatment on the enzymatic activity of immobilized inulinases. The effects of process variables were evaluated through 2³ experimental design. RESULTS: Inulinase from Klyveromyces marxianus NRRL Y‐7571 presented an increase of 163% in residual activity using LPG at 30 bar during 1 h exposure using a depressurization rate of 20 bar min^?1. For Aspergillus niger commercial inulinase, an increment of 129% in residual activity was observed at 30 bar for 1 h treatment at the highest depressurization rate (20 bar min^?1). Enzymatic activities changed significantly depending on the enzyme source and the experimental treatment conditions investigated, such as exposure time, depressurization rate and pressure. CONCLUSION: Hence, compressed LPG appears to be a promising technique with practical relevance as a preparation step to improve enzyme activity, thus helping the development of new biotransformation processes. © 2012 Society of Chemical Industry