Trihalomethanes in the drinking water of Concepción and Talcahuano,Chile

Formation of trihalomethanes (THMs) during water disinfection has been related to several health problems, although the magnitude of these effects is under discussion. This paper quantifies the THMs in drinking water from the Bío‐Bío Region of central Chile, the first since the modification of the national reference value (Nch 409/05) to include maximal values for THMs. THMs were quantified using a solid phase micro‐extraction (SPME) method and GC‐MS. The concentration ranges were 9.7–111.6, 0.1–1.0 and 0.9–25.5 μg/L for chloroform (CHCl₃), and dibromochloromethane (CHClBr₂) and bromodichloromethane (CHCl₂Br), respectively. Bromoform was not detected in any sample. There were good correlations (R²=0.91–0.98, P<0.001) between the THMs and the residence time of the water, the distance from the treatment plant and an inverse correlation to free chlorine in the water. The Additive Toxicity Index Value (0.07–1.00) showed that all samples were within the Chilean reference value for THMs in drinking water. However, several values were close to exceeding the maximum permitted concentration (200, 100, 100 and 60 μg/L for CHCl₃, CHBr₃, CHClBr₂ and CHCl₂Br, respectively), which may occur when the water demand is low and thus residence times are longer.     

Survival of Lactobacillus casei (LC-1) adhered to prebiotic vegetal fibers

This study evaluated the survival of Lactobacillus casei (LC-1) when adhered to four different dehydrated prebiotic fibers. After vacuum drying in oat bran with 9% β-glucan and green banana flour, LC-1 viability was 79% and 76%, respectively. Scanning electron microscopy images revealed no morphological changes in the cells adhered to these fibers, and the addition of trehalose as a cell protectant had a positive and significant effect on the survival of LC-1. At different storage temperatures, oat bran had the highest stability as well as in simulated gastrointestinal conditions, where LC-1 that adhered to the oat bran had greater viability (7.1 log CFU g^? 1) than in the free form (2.4 log CFU g^? 1). In the sensory evaluation, the probiotic oat bran added to a dairy fruit beverage was well accepted by consumers.Industrial relevanceThe diversification of food products and the growing interest in health life requires from food industry innovations and new products for this. Probiotic cultures into non-dairy products is still an innovation and a challenge to the functional food segment. The development of an oat bran with LC-1 adhered is important for the functional food industries because the probiotic can be viable during dehydration and storage at room temperature. In addition the LC-1 is protected under simulated gastrointestinal conditions without compromising sensory acceptability.     

Extracts of Mexican Oregano (<Emphasis Type="Italic">Lippia berlandieri</Emphasis> Schauer) with Antioxidant and Antimicrobial Activity

Antimicrobial activity of fractions obtained from Mexican oregano (Lippia berlandieri Schauer) chloroform extract was tested by growth inhibition against Escherichia coli, Staphylococcus aureus and Bacillus cereus, and antioxidant capacity was tested by inhibition of linoleic acid oxidation. Fractions were obtained by differences in polarity or structure (phenolic and non-phenolic fraction). Gram-positive organisms were more susceptible to Mexican oregano extracts. Fraction 3 (by polarity) and phenolic fractions I, II, III, IV and V were the extracts with higher antimicrobial activity. The non-phenolic fraction had effect against B. cereus. Polarity fraction 5 and phenolic Fraction II had a high antioxidant capacity; a 0.08% concentration of fraction 5 had a similar effect as butylated hydroxytoluene at 0.01% concentration. Fractions of Mexican oregano with different polarity and functional groups had antioxidant and antimicrobial activity and can be used in a variety of applications.     

Non-digestible fraction of cooked bean (Phaseolus vulgaris L.) cultivar Bayo Madero suppresses colonic aberrant crypt foci in azoxymethane-induced rats

The non-digestible fraction (NDF) of common bean (Phaseolus vulgaris L.) cultivar Bayo Madero was evaluated for its chemopreventive effect on azoxymethane (AOM) induced aberrant crypt foci (ACF) in rats. Diets containing cooked beans (CB) or its non-digestible fraction (NDF) were fed to 72 male rats after 2 azoxymethane injections (15 mg kg(-1) of body weight once a week for 2 weeks). ACF number, short chain fatty acids (SCFA) and β-glucuronidase activity were measured in colon sections from rats sacrificed 7 weeks after the last AOM injection. Food intake and weight gain of rats were unaffected by CB and NDF. CB and NDF suppressed the AOM-induced formation of ACF (0.8 and 1.5 ACF/distal zone, respectively vs. 6.6 ACF/distal zone based on methylene blue stain) and lowered β-glucuronidase activity in cecal, colonic and fecal content compared to AOM group. SCFA production was not significantly different among fecal, cecal and colonic content. These results indicate that CB and NDF from Bayo Madero provide direct chemoprotection against early stage of azoxymethane (AOM)-induced colon cancer in rats.     

Cu/low-k dielectric TDDB reliability issues for advanced CMOS technologies

With the wide application of low-k and ultra-low-k dielectric materials at the 90 nm technology node and beyond, the long-term reliability of such materials is rapidly becoming a critical challenge for technology qualification. Low-k time-dependent dielectric breakdown (TDDB) is usually considered as one of the most important reliability issues during Cu/low-k technology development because low-k materials generally have weaker intrinsic breakdown strength than traditional SiO₂ dielectrics. This problem is further exacerbated by the aggressive shrinking of the interconnect pitch size due to continuous technology scaling. In this paper, three critical issues of low-k TDDB characteristics during low-k development and qualification will be reviewed. In the first part, a low-k TDDB field acceleration model and its determination will be discussed. In the second part, low-k dielectric time-to-breakdown (t_BD) statistical distribution and TDDB area scaling law for reliability projection will be examined. In the last part, as low-k TDDB has been found to be sensitive to all aspects of integration, the effects of process variations on low-k TDDB degradation will be demonstrated. Some key aspects which need to be carefully addressed to control overall low-k TDDB performance from process and integration side will be discussed.     

Production of Bioactive Peptides from Lactic Acid Bacteria: A Sustainable Approach for Healthier Foods

Traditional fermented foods where lactic acid bacteria (LAB) are present have been associated with beneficial effects on human health, and some of those benefits are related to protein‐derived products. Peptides produced by LAB have attracted the interest of food industries because of their diverse applications. These peptides include ribosomally produced (bacteriocins) and protein hydrolysates by‐products (bioactive peptides), which can participate as natural preservatives and nutraceuticals, respectively. It is essential to understand the biochemical pathways and the effect of growth conditions for the production of bioactive peptides and bacteriocins by LAB, in order to suggest strategies for optimization. LAB is an important food‐grade expression system that can be used in the simultaneous production of peptide‐based products for the food, animal, cosmetic, and pharmaceutical industries. This review describes the multifunctional proteinaceous compounds generated by LAB metabolism and discusses a strategy to use a single‐step production process, using an alternative protein‐based media. This strategy will provide economic advantages in fermentation processes and will also provide an environmental alternative to industrial waste valorization. New technologies that can be used to improve production and bioactivity of LAB‐derived peptides are also analyzed.     

Gallic Acid‐Loaded Zein Nanoparticles by Electrospraying Process

Currently, electrospraying is a novel process for obtaining the nanoparticles from biopolymers. Zein nanoparticles have been obtained by this method and used to protect both hydrophilic and hydrophobic antioxidant molecules from environmental factors. The objective of this work was to prepare and characterize gallic acid‐loaded zein nanoparticles obtained by the electrospraying process to provide protection to gallic acid from environmental factors. Thus, it was related to the concentration of gallic acid in physicochemical and rheological properties of the electrosprayed solution, and also to equipment parameters, such as voltage, flow rate, and distance of the collector in morphology, and particle size. The physicochemical properties showed a relationship in the formation of a Taylor cone, in which at a low concentration of gallic acid (1% w/v), low viscosity (0.00464 ± 0.00001 Pa·s), and density (0.886 ± 0.00002 g/cm³), as well as high electrical conductivity (369 ± 4.3 µs/cm), forms a stable cone‐jet mode. The rheological properties and the Power Law model of the gallic acid‐zein electrosprayed solution demonstrated Newtonian behavior (n = 1). The morphology and size of the particle were dependent on the concentration of gallic acid. Electrosprayed parameters with high voltage (15 kV), low flow rate (0.1 mL/hr), and short distance (10 cm) exhibited a smaller diameter and spherical morphology. FT–IR showed interaction in the gallic acid‐loaded zein nanoparticle by hydrogen bonds. Therefore, the electrospraying process is a feasible technique for obtaining gallic acid‐loaded zein nanoparticles and providing potential protection to gallic acid from environmental factors.     

Acetylation of hydroxytyrosol enhances its transport across differentiated Caco-2 cell monolayers

Hydroxytyrosol and hydroxytyrosyl acetate are two well-known phenolic compounds with antioxidant properties that are present in virgin olive oil. Since the in vivo biological activity of polyphenols is dependent on their intestinal absorption and metabolism, the absorption of hydroxytyrosol and hydroxytyrosyl acetate and the extent to which they are conjugated and metabolised during transfer across intestinal Caco-2/TC7 cell monolayers, was investigated. LC-DAD and LC-MS were used for the quantification and identification of metabolites. Further evidence was obtained by observing metabolite susceptibility to β-glucuronidase treatment and by comparison of products of in vitro conjugation reactions of authentic phenolics with those produced by the CaCo-2 cells. Homovanillyl alcohol was the only conjugate detected as a result of hydroxytyrosol metabolism, and accounted for 20% of the total metabolites detected in the basolateral compartment after 2 h of incubation. Hydroxytyrosyl acetate was largely converted into free hydroxytyrosol (38.4%) and subsequently metabolised into homovanillyl alcohol (6.7%). In addition, hydroxytyrosyl acetate glucuronide (17.4%) together with non-metabolised hydroxytyrosyl acetate (37.5%) were also detected. Both hydroxytyrosyl acetate and hydroxytyrosol were transferred across human Caco-2/TC7 cell monolayers, but the acetylated compound exhibited an apparent permeability (Papp_AP→BL/Papp _BL→AP) 2.1-fold higher than free hydroxytyrosol. For both compounds, all conjugates were preferentially transported to the basolateral side. These results show that the acetylation of hydroxytyrosol significantly increases its transport across the small intestinal epithelial cell barrier, and supports further research into hydroxytyrosyl acetate as a hydroxytyrosol prodrug offering enhanced bioavailability.     

Synthesis,characterization and rheological properties of multiblock associative copolymers by RAFT technique

Polymer Bulletin - Preparation of associating multiblock copolymer electrolytes mediated by radical addition–fragmentation chain transfer (RAFT) technique has been evaluated and reported in...