Interaction of peptides obtained from the enzymatic hydrolysis of soybean meal with cyclodextrins: an evaluation of bitterness reduction

Enzymatic hydrolysis improves the functional and nutritional characteristics of soybean meal proteins. However, the presence of hydrophobic peptides can cause an intense bitterness to the hydrolysate, which is deleterious in terms of final product taste. In this paper we evaluate the interaction of peptides employed for the enzymatic hydrolysis of soybean meal with α-, β- and γ-cyclodextrins, aiming to reduce the bitter taste. Each cyclodextrin was added in mass fractions of 1.5, 2.0 and 2.5% in a hydrolysate of soybean meal prepared with enzyme Alcalase^® 2.4 L at 1% concentration (protein/protein). In order to identify possible interactions between the components, several instrumental techniques were employed. NMR H¹ spectra evidenced strong interactivities between the peptides’ aromatic and aliphatic regions and the cyclodextrins’ internal cavities. Analysis by an electronic tongue system showed that the addition of α- and β-cyclodextrins to the hydrolysate, at concentrations 1.5 and 2.0% (w/w), respectively, induced the greatest difference with regard to control hydrolysate. The difference was also sensory perceptible to untrained tasters in a bitterness ranking test, and reveal that the treatment was efficient in reducing bitterness compared to the control samples, indicating this method as a suitable approach for masking bitterness in soybean hydrolysates.     

A minimization algorithm for equilibrium problems with polyhedral constraints

Our aim in this paper is to study an infeasible interior proximal method for solving equilibrium problems with polyhedral constrains in a quasiconvex setting. Under mild assumptions, we show that the sequence generated by our algorithm is well defined and it converges to a solution of the problem when regularization parameters converge to zero.     

Nonautonomous and non periodic Schrödinger equation with indefinite linear part

The existence of solution of the nonlinear Schrödinger equation

$$\begin{aligned} \begin{array}{lc} -\Delta u + V(x) u = f(x,u),&\end{array} \end{aligned}$$

is stablished in \(\mathbb {R}^N\), where V changes sign and f is an asymptotically linear function at infinity, with V and f non periodic in x. Spectral theory, a classical linking theorem and interaction between translated solutions of the problem at infinity are employed.

     

Mechanical,thermal and barrier properties of pectin/cellulose nanocrystal nanocomposite films and their effect on the storability of strawberries (Fragaria ananassa)

In this work, two formulations of pectin/cellulose nanocrystals/glycerol nanocomposites were employed as packaging to extend storage life of strawberries. The effects of incorporating cellulose nanocrystals extracted from bleached Kraft wood pulp on the mechanical, thermal, and barrier properties of pectin‐based nanocomposites were evaluated. Nanocomposite films with different filler levels of cellulose nanocrystals (1, 2, 4 and 8% w/w) were prepared by casting. Compared with the neat film of pectin, improvements in the mechanical properties of the nanocomposites were observed, but these films became fragile. To improve the film flexibility, glycerol was added as a plasticizer and then new variations in the mechanical, thermal, and barrier properties of these nanocomposites were evaluated. The effects of nanocomposite films on storability of strawberries were compared with Poly vinyl chloride packaging films. The Poly vinyl chloride film and the nanocomposites showed similar behavior regarding weight loss by the strawberries, especially in the initial days of storage. The results show that pectin/cellulose nanocrystals/glycerol nanocomposites could be considered as a viable packaging alternative for replaced the Poly vinyl cloride film. Copyright © 2015 John Wiley & Sons, Ltd.     

Analysis of rheological properties of fiber suspensions in a Newtonian fluid by direct fiber simulation. Part 3: Behavior in uniaxial extensional flows

The present work presents a predictive direct fiber simulation of fiber suspensions under uniaxial extensional flows by Stokesian dynamics, considering both near- and farfield hydrodynamic intrafiber interactions and lubrication approximation for interfibers. Initially, code validation is performed and simulation predictions compared with experimental data. Afterwards, the orientation tensor under flow is discussed as a function of volume fraction, aspect ratio and flexibility. Based on the results, a general constitutive equation with a proposed parameter is proposed and verified by comparing experimental data of high volume fraction and high aspect ratio systems.     

Lyotropic mixture made of potassium laurate/1-undecanol/K2SO4/water presenting high birefringences and large biaxial nematic phase domain: a laser conoscopy study

We present a numerical study of the shape taken by a spherical elastic surface when the volume it encloses is decreased. For the range of 2D parameters where such a surface may model a thin shell of an isotropic elastic material, the mode of deformation that develops a single depression is investigated in detail. It occurs via buckling from sphere toward an axisymmetric dimple, followed by a second buckling where the depression loses its axisymmetry through folding along portions of meridians. For the thinnest shells, a direct transition from the spherical conformation to the folded one can be observed. We could exhibit unifying master curves for the relative volume variation at which first and second buckling occur, and clarify the role of Poisson??s ratio. In the folded conformation, the number of folds and inner pressure are investigated, allowing us to infer shell features from mere observation and/or knowledge of external constraints.     

Structural Design,Synthesis and Antioxidant,Antileishmania, Anti-Inflammatory and Anticancer Activities of a Novel Quercetin Acetylated Derivative

Quercetin (Q) is a bioflavonoid with biological potential; however, poor solubility in water, extensive enzymatic metabolism and a reduced bioavailability limit its biopharmacological use. The aim of this study was to perform structural modification in Q by acetylation, thus, obtaining the quercetin pentaacetate (Q5) analogue, in order to investigate the biological potentials (antioxidant, antileishmania, anti-inflammatory and cytotoxicity activities) in cell cultures. Q5 was characterized by FTIR, ¹H and ¹³C NMR spectra. The antioxidant potential was evaluated against the radical ABTS^•+. The anti-inflammatory potential was evaluated by measuring the pro-inflammatory cytokine tumor necrosis factor (TNF) and the production of nitric oxide (NO) in peritoneal macrophages from BALB/c mice. Cytotoxicity tests were performed using the AlamarBlue method in cancer cells HepG2 (human hepatocarcinoma), HL-60 (promyelocytic leukemia) and MCR-5 (healthy human lung fibroblasts) as well as the MTT method for C6 cell cultures (rat glioma). Q and Q5 showed antioxidant activity of 29% and 18%, respectively, which is justified by the replacement of hydroxyls by acetyl groups. Q and Q5 showed concentration-dependent reductions in NO and TNF production (p < 0.05); Q and Q5 showed higher activity at concentrations > 40µM when compared to dexamethasone (20 µM). For the HL-60 lineage, Q5 demonstrated selectivity, inducing death in cancer cells, when compared to the healthy cell line MRC-5 (IC₅₀ > 80 µM). Finally, the cytotoxic superiority of Q5 was verified (IC₅₀ = 11 µM), which, at 50 µM for 24 h, induced changes in the morphology of C6 glioma cells characterized by a round body shape (not yet reported in the literature). The analogue Q5 had potential biological effects and may be promising for further investigations against other cell cultures, particularly neural ones.