Phenolic compounds profile and antioxidant capacity of 'Ataulfo' mango pulp processed by ohmic heating at moderate electric field strength.

Heat treatment during pasteurization of mango (Mangifera indica L.) pulp reduces the phenolic content and its potential health benefits. The bioactive content, phenolics profile, and antioxidant capacity of 'Ataulfo' mango pulp after ohmic heating (OH) treatment (15.0-20.0 V/cm), and conventional heating (CT, 72 °C) were evaluated. No significant differences were observed in the gallic acid and mangiferin content and its antioxidant capacity (ABTS). Mass spectrometry analysis (LC/MS-TOF) showed that all treatments produced the same profile of phenolic compounds, including 6 phenolic acids, 2 gallotannins, 1 benzophenone, 2 xanthones, and 3 flavonoids. PCA analysis confirmed that mangiferin and gallic acid were the main contributors to the ABTS antioxidant capacity. These results demonstrate that OH treatments can preserve the compositions of phenolic compounds mango pulp, thus maintaining its potential health benefits.

Adsorption kinetics and Box-Behnken design optimization for organic dyes on tungsten oxide.

Transition metal oxides have been applied to degrade organic dyes found in water bodies via photocatalysis. To do it, however, is essential that the dye molecules adsorb onto the metal oxide surface. Thus, optimizing the adsorption capacity of the adsorbent increases the probability of reaction between oxidation radicals and organic dye molecules and maximizes the effectiveness per gram of photocatalyst. With this in mind, we studied the adsorption behavior of Methylene Blue (MB) and Acid Orange 7 (AO7), two commonly found pollutants, as a function of dilution's pH, WO3 load, and initial dye concentration. We found out that WO3 adsorbs up to 80% of MB at pH = 6, and 13% of AO7 at pH = 2, although it is unable to adsorb AO7 at the natural pH of the dye dilution. Assuming a pseudo-second order kinetics model for the analysis of the MB adsorption amount, we determined a rate constant k2 = 6 × 10-2(g · mg-1)/min for the adsorption process. We put forward a molecular model for adsorption, driven by concentration gradients and electrostatic interactions. Finally, from a statistical analysis, we determined that pH is the most significant factor for the adsorption of MB and AO7 on WO3, reinforcing the notion that electrostatic interactions are the main mechanism driving the adsorption process. The Box-Behnken design optimization also evinces the key playing role of WO3 load in the adsorption percentage of AO7 and let us establish the optimal load required to maximize adsorption.

Dietary supplementation of lutein reduces colon carcinogenesis in DMH-treated rats by modulating K-ras, PKB, and ß-catenin proteins.

In colon cancer, disturbances have been detected in genes coding for proteins involved in cellular proliferation, such as K-ras, ß-catenin, extracellular signal-regulated kinases (ERKs), and the protein kinase B (PKB). Although carotenoids such as lutein have an important role to prevent and treat some types of cancer, there are very few studies about the effect of lutein against colon cancer and its activity at the molecular level. Therefore, the aim of this study was to evaluate the chemoprotective activity of lutein against colon cancer induced by dimethylhydrazine (DMH). The results showed a significant increase in protein expression for K-ras and ß-catenin in tumors of DMH-treated rats. Simultaneously, we detected changes in the phosphorylation state of ERK1/2 and PKB in DMH-treated animals. Lutein given in the diet (0.002%), before (prevention) and after (treatment) DMH administration, diminished the number of tumors by 55% and 32%, respectively. Moreover, lutein significantly decreased in tumors the expression of K-ras (25%) and ß-catenin (28%) and the amount of pPKB (32%), during the prevention, and 39%, 26%, and 26% during the treatment stage, respectively. This study demonstrates the chemoprotective effect of lutein against colon cancer by modulating the proliferative activity of K-ras, PKB, and ß-catenin proteins.

Effect of light and sweeteners on color in an amaretto-type liqueur.

Studies on the color loss in an amaretto-type liqueur under controlled light conditions showed a clear dependence of the decoloration rate on the light intensity, and complete color stability in the absence of light. The principal sweetener used in the preparation of the liqueur strongly affected the rate of color loss under irradiation, color stability being much greater for the formulations containing sucrose or no added sweetener instead of fructose 42. These differences were more pronounced in experiments conducted with chemically well-defined mixtures that contained either of the 2 azo dyes used in the coloration of the amaretto, tartrazine, and Allura Red, and various alternative sweeteners, in 28% (v/v) ethanol solution: D-fructose and, to a lesser extent, D-glucose, at concentrations of 14% (w/v), were effective in bringing about photodecoloration, while no color loss was detected in the presence of sucrose, or in the absence of any added sugar. The results are interpreted in terms of a redox reaction of reducing sugars with the diarylazo compounds, the function of the light being the conversion of the azo compound from the predominant trans configuration to the cis configuration, which on geometric grounds lends itself better to a concerted, cyclical redox reaction with the reducing sugar.