Effect of ingestion of dark chocolates with similar lipid composition and different cocoa content on antioxidant and lipid status in healthy humans

The association between in vitro antioxidant capacity of dark chocolates with different cocoa percentage and the in vivo response on antioxidant status was investigated. In a randomized crossover design, 15 healthy volunteer consumed 100 g of high antioxidants dark chocolate (HADC) or dark chocolate (DC). In vitro, HADC displayed a higher Total Antioxidant Capacity (TAC) than DC. In vivo, plasma TAC significantly peaked 2 h after ingestion of both chocolates. TAC levels went back to zero 5 h after DC ingestion whilst levels remained significantly higher for HADC. HADC induced a significantly higher urinary TAC in the 5-12 h interval time than DC. No change was detected in urinary excretion of F2-isoprostanes. Plasma thiols and triacylglycerol (TG) levels significantly increased for both chocolate with a peak at 2 h remaining significantly higher for DC after 5 h respect to HADC. Results provide evidence of a direct association between antioxidant content of chocolate and the extent of in vivo response on plasma antioxidant capacity.     

Experimental approaches for the estimation of uncertainty in analysis of trace inorganic contaminants in foodstuffs by ICP-MS

Total Diet Studies to estimate dietary exposure to food contaminants need to evaluate laboratory measurements data variance. In this process it is critical that data from analytical methods are reliable to correctly scrutinize and compare values over time and between countries. In Europe it is widely recognized that the evaluation of measurement uncertainty is an important parameter when assessing the sources of analytical data variability. Two approaches are considered to estimate uncertainty in analytical measurement. Arsenic, Lead, Chromium and Cadmium, content in several food matrix determined by Inductively Coupled Mass Spectrometry (ICP-MS) microwave digestion assisted, are used as examples. The aim of the present research work is to compare both approaches accepted by Eurolab and GUM: Mathematical modeling to assess uncertainty components based on a classical model (bottom up) and an empirical method (top down), based on either experimental data obtained from a single laboratory validation data or inter-laboratory data from Proficiency Testing schemes. Relative expanded uncertainty calculated by both approaches agree when U (%) <20%. These values are concordant with RSD_R reported in collaborative studies of EN 15763 (2009), which were assumed as target uncertainty. The top down approach described is simple and easy to use when compared with the mathematical modeling approach providing considerable benefits to those who assess data produced by several laboratories.     

Multistage treatment system for raw leachate from sanitary landfill combining biological nitrification–denitrification/solar photo-Fenton/biological processes,at a scale close to industrial – Biodegradability enhancement and evolution profile of trace pollutants

A multistage treatment system, at a scale close to the industrial, was designed for the treatment of a mature raw landfill leachate, including: a) an activated sludge biological oxidation (ASBO), under aerobic and anoxic conditions; b) a solar photo-Fenton process, enhancing the bio-treated leachate biodegradability, with and without sludge removal after acidification; and c) a final polishing step, with further ASBO.     

Whey fractionation through the membrane separation process

The aim of this work is to improve the utilisation of fractions of whey through membrane separation processes. From a solution of whey treated by ultrafiltration (UF) associated with diafiltration (DF), two streams were obtained: a concentrate and a permeate. In this process, a purified protein concentrate with about 70% of protein was obtained. Permeate was treated by electrodialysis (ED) to obtain a fraction rich in lactose (90%). The final effluent was treated by reverse osmosis (RO) in order to recover water free of salts. RO made it possible to recover 50% water and retain 85% of the salts.     

SEM and AFM characterization of surface of two RMGICs for degradation before and after modification with bioactive glass ceramic

Objectives: The aim of this study was to evaluate the effect of bioactive glass–ceramic particles (Biosilicate®) addition on surface nanoroughness and topography of Resin-modified glass ionomer cements (RMGICs).

Methods: Experimental materials were made by incorporating 2 wt% of Biosilicate® into Fuji II LC® (FL) and Vitremer® (VT) powders. Disks of RMGICs (with and without Biosilicate®) measuring 0.5 cm (diameter) × 0.5 mm (thickness) were fabricated and polished. Samples were stored at 37 °C in dry or immersed in distilled water for 30 days. Digital images (20 × 20 μm) from the surfaces were obtained by means of an atomic force microscopy. Three images were acquired for each sample, and four nanoroughness measurements were performed in each image. Nanoroughness (Ra, nm) was assessed by Nanoscope Software V7. Data were analyzed with ANOVA and Student–Newman–Keuls multiple comparisons (p < 0.05). SEM images were obtained for surface topography analysis.

Results: FL was significantly rougher than VT (p < 0.05) in wet and dry conditions. The addition of Biosilicate® increased the surface roughness in VT and decreased in FL, regardless of the storage media (p ≤ 0.05). No differences existed between materials and storage conditions after Biosilicate® addition. Significance: The Biosilicate® particles addition produced changes on the surface nanoroughness of the RMGICs. These changes depended on the particles size of the original cements in dry conditions. In water storage, dissolution of the Biosilicate® particles, a silica-rich gel formation, and a hydroxyl carbonate apatite precipitation on the surface of the materials changed the nanoroughness surface. FL was the roughest in both conditions.

Significance: The Biosilicate® particles addition produced changes on the surface nanoroughness of the RMGICs. These changes depended on the particles size of the original cements in dry conditions. In water storage, dissolution of the Biosilicate® particles, a silica-rich gel formation, and a hydroxyl carbonate apatite precipitation on the surface of the materials changed the nanoroughness surface. FL was the roughest in both conditions.     

Thermo‐responsive polyurethane hydrogels based on poly(ethylene glycol) and poly(caprolactone): Physico‐chemical and mechanical properties

In this work, we present the synthesis and characterization of chemically crosslinked polyurethanes (PU) composed of poly(ethylene glycol) (PEG) and poly(caprolactone) diol (PCL‐diol), as hydrophilic and hydrophobic segments respectively, poly(caprolactone) triol (PCL‐triol), to induce hydrolysable crosslinks, and hexamethylene diisocyanate (HDI). The syntheses were performed at 45 °C, resulting in polyurethanes with different PEG/PCL‐diol/PCL‐triol mass fractions. All the PUs are able to crystallize and their thermal properties depend on the global composition. The water uptake capacities of the PU increase as the PEG amount increases. The water into hydrogels is present in different environments, as bounded, bulk and free water. The PU hydrogels are thermo‐responsive, presenting a negative dependence of the water uptake with the temperature for PEG rich networks, which gradually changes to a positive behavior as the amount of poly(caprolactone) (PCL) segments increases. However, the water uptake capacity changes continuously without an abrupt transition. Scanning electron microscopy (SEM) analyses of the hydrogel morphology after lyophilization revealed a porous structure. Mechanical compression tests revealed that the hydrogels present good resilience and low recovery hysteresis when they are subject to cycles of compression–decompression. In addition, the mechanical properties of the hydrogels varies with the composition and crosslinking density, and therefore with the water uptake capacity. The PU properties can be tuned to fit for different applications, such as biomedical applications. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43573.     

Characterization of Crude and Partially Purified Lipase from Geotrichum candidum Obtained with Different Nitrogen Sources

Lipases from Geotrichum candidum were produced in two different medium: A = 12 % (w/v) clarified corn steep liquor (CCSL) + 0.6 % (w/v) soybean oil (SO) and B = 3.5 % (w/v) yeast hydrolysate (YH) + 0.7 % (w/v) SO. Lipases were partially purified from both media by hydrophobic interaction chromatography using 3.0 mol L^?1 of NaCl as mobile phase, and they were characterized in the crude and partially purified forms. The recovery of lipase activity from CCSL and YH via HIC were 96 and 94.3 %, and the purification factors were 44.3 and 86.7‐fold, respectively. All evaluated lipases had similar optimum pH (7.0–7.7), but, for the CCSL crude lipase, optimum temperature (47 °C) was 10 °C higher than others lipases evaluated. CCSL crude lipase possessed a higher thermo stability than YH crude lipase, e.g., at 37 °C (pH 7.0) the half‐life of CCSL crude lipase was 19.25 h and at pH 8.0 (30 °C) the half‐life was 48 h, which are five and ten times higher than with YH crude lipase, respectively. On the other hand, the YH crude lipase possessed a higher catalytic constant (k_cat = 2.3 min^?1) but with almost the same catalytic efficiency (K_m/k_cat = 32.12 mg mL min^?1) in relation to CCSL crude lipase. The lipases differ in biocatalytic properties between substrates, suggesting that the two lipases can be employed for different applications.