Uptake of glucose analogues by rat brain cortex slices: Na+-independent membrane transport

Canine tracheal mucus was dissolved by a number of mucolytic agents, including disulfide bond reducing agents, hydrogen bond breaking agents, and chaotropic ions, and their effect on rheological properties was assessed. Sodium thiocyanate led to 85-100% dissolution with the maximum retention of elasticity. Thiocyanate exposure did not result in demonstrable alterations in the size or shape of the mucus glycoproteins. Sodium thiocyanate is therefore recommended as a suitable dispersing agent for physiochemical studies of glycoprotein secretions.     

Effects of a citrus based juice on biomarkers of oxidative stress in metabolic syndrome patients

Bioactive substances found in numerous foods can be successfully and safely used to modify various cellular functions and affect the oxidative stress. The aim of this study was to analyze the effect of a citrus-based juice (juice citrus (95%) with 5% of aronia extract (Aronia melanocarpa)) on biomarkers of oxidative stress in patients with metabolic syndrome compared with healthy individuals. The study comprised 20 healthy subjects and 33 patients with metabolic syndrome. Eighteen patients consumed daily 300 mL of a citrus-based juice during 6 months and 15 patients consumed 300 mL of a placebo beverage. The control group consumed a citrus-based juice (CJ). Before, and at sixth months after consuming of a citrus-based juice the following parameters were determined: 15-isoprostane F₂, 8-hydroxydeoxyguanosine (8-OHdG), reduced and oxidized glutathione (GSH/GSSH), carbonyl groups and oxidized LDL (ox-LDL). After consuming CJ during 6 months the values of 8-OHdG, carbonyl groups and LDL-ox decreased in both analyzed groups and the values of GSH/GSSH increased. Significant differences were observed in both groups. Thus consumption of citrus-based juice improved the biomarkers of oxidative stress in metabolic syndrome patients.     

Dispersive Liquid–Liquid Microextraction Followed by Capillary High-Performance Liquid Chromatography for the Determination of Six Sulfonylurea Herbicides in Fruit Juices

In this study a simple, rapid, and efficient method has been developed for the determination of six sulfonylurea herbicides (SUHs): triasulfuron, metsulfuron-methyl, chlorsulfuron, flazasulfuron, chlorimuron-ethyl, and primisulfuron-methyl in commercial grape and apple juice samples, using dispersive liquid–liquid microextraction coupled with capillary high-performance liquid chromatography with diode array detection. Various parameters that influence the extraction efficiency, such as the type and volume of extraction and disperser solvents, sample pH, and salt addition, were investigated and optimized. Under the optimum conditions, limits of detection and quantification of the method were in the ranges of 2–9 and 8–29 μg L^?1, respectively, lower than the maximum residue limits set by the European Union for the raw fruits, such as grape and apple. The intra- and inter-day relative standard deviations varied from 1.0 to 8.2 and 1.8 to 9.8 %, respectively, with recoveries between 72.0 and 109.5 % for commercial grape (both white and red) and apple juice samples, showing satisfactory accuracy for the determination of SUHs in fruit juices.     

Application of Fast Gas Chromatography–Mass Spectrometry in Combination with the QuEChERS Method for the Determination of Pesticide Residues in Fruits and Vegetables

A fast gas chromatography–mass spectrometry method has been developed for multiresidue determination of up to 56 pesticides in fruits and vegetables in a chromatographic run time of <10 min, using a single quadrupole mass spectrometer operating in selected ion monitoring mode. The well-known acetate-buffering version of the QuEChERS method has been used for sample preparation. Programmable temperature vaporizer injection of 3 μL allowed reaching limits of detection between 0.15 and 15 μg/kg for most compounds in the sample matrices tested. The applicability of the method has been evaluated in apple, orange, carrot, and tomato. Recoveries at three fortification levels (0.01, 0.1 and 0.5 mg/kg) ranged from 70 to 120 % for most compounds, with relative standard deviations below 20 % in all cases. The developed method has been applied to fruit and vegetable samples from different Spanish provinces.     

Investigations into acrylamide precursors in sterilized table olives: Evidence of a peptic fraction being responsible for acrylamide formation

Formation of acrylamide from commercial model peptides containing protein-bound aspartic acid, alanine and methionine, respectively, at 200 °C and different times in the absence of any carbonyl sources, was demonstrated by HPLC–MS/MS analyses. Further experiments using a more complex model system based on olive water, i.e., the aqueous fraction of olive pulp from untreated and lye-treated green olives, were performed. After partial fractionation of olive water by solid-phase extraction, only peptides/proteins containing fractions, being devoid of free asparagine, generated significant amounts of acrylamide during less harsh heat treatment (121 °C for 30 min). In contrast, acrylamide was not detected after heating the same fraction under identical thermal conditions when previously subjected to acid hydrolysis. Consistently, significant amounts of acrylamide were released after heating the albuminous precipitate resulting from acetone precipitation of olive water. These results strongly support the role of peptides/proteins as precursors of acrylamide formation in sterilized olives.     

Transcriptional and functional responses of Escherichia coli O157:H7 growing in the lettuce rhizoplane

Lettuce and spinach are increasingly implicated in foodborne illness outbreaks due to contamination by Escherichia coli O157:H7. While this bacterium has been shown to colonize and survive on lettuce leaf surfaces, little is known about its interaction with the roots of growing lettuce plants. In these studies, a microarray analyses, mutant construction and confocal microscopy were used to gain an understanding of structure and function of bacterial genes involved in the colonization and growth of E. coli O157:H7 on lettuce roots. After three days of interaction with lettuce roots, 94 and 109 E. coli O157:H7 genes were significantly up- and down-regulated at least 1.5 fold, respectively. While genes involved in biofilm modulation (ycfR and ybiM) were significantly up-regulated, 40 of 109 (37%) of genes involved in protein synthesis were significantly repressed. E. coli O157:H7 was 2 logs less efficient in lettuce root colonization than was E. coli K12. We also unambiguously showed that a ΔycfR mutant of E. coli O157:H7 was unable to attach to or colonize lettuce roots. Taken together these results indicate that bacterial genes involved in attachment and biofilm formation are likely important for contamination of lettuce plants with Shiga toxin-producing E. coli strains.     

Innovative Quality Improvement by Continuous Microwave Processing of a Faba Beans Pesto Sauce

Nowadays, consumers demand healthy, safe, and ready-to-eat horticultural products because of their lifestyle. In this regard, new legume-based food product development with eco-innovative technologies seems to be an interesting market. The effect on quality of an innovative pesto sauce, made of fresh faba bean seeds, of an alternative continuous microwave treatment pasteurization (MW, 11 kW; 30 s) regarding a conventional pasteurization (85 °C; 5 min) throughout 20 days at 5 °C was studied. Non-heated blended samples were used as control. The microbial quality was satisfactory in all treatments. MW treatment improved the sensorial quality of pesto sauce and decreased condensed tannins. Additionally, MW-treated samples showed the best texture, consistency, and color, preserving its chlorophyll and carotenoid content. On the other hand, thermal treatments showed a decrease in total phenolic compounds (TPC) and antioxidant capacity (TEAC) after heating, regarding control samples; however, TPC and TEAC remained quite constant throughout the storage.     

In vitro digestibility of phenolic compounds from edible fruits: could it be explained by chemometrics?

The health benefits of phenolic compounds depend on the ingested amount, molecular diversity and gastrointestinal digestibility. The phenolic profile of eight fruits (blackberry, blueberry, strawberry, raspberry, mulberry, pomegranate, green and red globe grapes) was chemometrically associated with their in vitro digestibility (oral, gastric, intestinal). Extractable phenols, flavonoids and anthocyanins strongly correlated with each other (r ≥ 0.84), proanthocyanidins with anthocyanins (r = 0.62) and hydrolysable phenols with both extractable phenols (r = 0.45) and proanthocyanidins (r = ?0.54). Two principal components explained 93% of the variance [61% (free‐phenols), 32% (bounded‐phenols)], and four clusters were confirmed by hierarchical analysis, based in their phenolic richness (CLT 1‐4: low to high) and molecular diversity. In vitro digestibility of extractable phenols and flavonoids was blackberry (CLT‐4)> raspberry (CLT‐2)> red grape (CLT‐1) related to their phenolic richness (r ≥ 0.96; P < 0.001), but anthocyanins’ digestibility was pH‐dependent. Chemometrics is useful to predict the in vitro digestibility of phenolic compounds in the assayed fruits.     

Enhancement effect on apparent viscosity of aqueous tragacanth gum dispersions promoted by sugars

Flow curves of aqueous dispersions of tragacanth gum (T) with sucrose and glucose at different temperatures were determined using a controlled‐stress rheometer. The effect of sodium chloride without or with sucrose (at the highest content) on the rheology of T dispersions was evaluated. The presence of sucrose and glucose promoted a noticeable enhancement impact on the apparent viscosity of aqueous T dispersions, which depended on sugar type/content, shear rate and temperature. In all cases, the glucose addition led to the largest enhanced viscosities at low shear rates (<10 s^?1) and temperature. The joint action of sugar and salt exhibited a notable effect on apparent viscosity at low shear rates, softening the strong shear‐thinning behaviour of T samples. Flow curves of T in the presence of sugars were satisfactorily described by the Cross‐Williamson model, being semi‐empirical correlations of the model parameters with ingredients content and temperature stablished.     

The Effect of Hybrid Carrageenan on the Thermo-rheological Properties of Gluten-Free Flour Doughs Using a Modified Kneading Protocol

Thermo-rheological behaviour of chestnut flour doughs supplemented with kappa/iota-hybrid carrageenan (HC) (up to 2.0%, flour basis (f.b.)) and sodium chloride (1.8%, f.b.) was determined at both target (C1) and final (C5) mixing peaks. For this purpose, small amplitude oscillatory shear (0.01 to 100 Hz), creep–recovery (loading of 50 Pa for 60 s, 30 °C), temperature sweeps (from 30 up to 180 °C) and heating/cooling cycles (between 30 and 60 °C) were conducted on a controlled stress rheometer. Previously, the thermal-mixing behaviour at proposed mixing temperature (50 °C) was conducted on Mixolab® apparatus. Results showed that the dough stability (from 2.2 to 5.8 min) in mixing stage and starch heat resistance to dough processing were significantly improved at proposed mixing temperature, even in the absence of HC. No statistical differences in rheological properties were observed for doughs evaluated in C1; however, those analysed in C5 were significantly modified in the presence of HC, mainly in terms of viscous behaviour (from 52.1 × 10⁶ to 39.1 × 10⁶ Pa s). Creep–recovery data sets, successfully fitted using Burgers model, revealed that the elasticity (J _r/J _max from 73.3 to 87.6%) of doughs analysed in C5 improved with HC addition. Thermal tests showed that the starch transitions were significantly promoted and stabilized with HC addition.