Evaluation of the flour and starch from white and purple varieties of mapuey (Dioscorea trifida)

Mapuey (Dioscorea trifida), is a tropical America tuber, which is appreciated for its taste and fine texture. It has not been fully cultivated in Venezuela, even though products like its flour and starch could replace conventional used products. In this work physical and chemical characteristic of flours from mapuey (varieties white and purple), were assessed, as well as some of their micronutrients. Physical, physicochemical and rheological properties, and chemical composition of isolated starches were also evaluated. Flours were obtained by a drying process and starches by aqueous extraction. Chemical analysis was performed following standard methodologies. The flour yield of purple mapuey was the highest, as was its protein content. The minerals content, showed significant differences between both varieties, presenting purple variety a higher content. Isolated starches showed high purity, this was corroborated by the scanning electron microscopy which showed irregular shaped granules (oval and elongated), with truncated end and smooth surfaces. Purple mapuey granules were smaller. Both varieties exhibited a B type diffraction pattern. The greater swelling power and water absorption capacity was presented by white mapuey, while the highest solubility was shown by the purple one. The white mapuey had maximum viscosity, as well as the highest value of breakdown, suggesting more fragile granules. Setback was lower in the white mapuey, suggesting lower tendency to retrogradation. The purple mapuey although, it showed a higher amylose content, presented lower consistency, even though the difference was not relevant.     

Milk thickeners do not influence anthropometric indices in childhood

BACKGROUND: Pediatric obesity is an important risk factor for chronic diseases in adulthood. Some infant feeding practices may contribute to childhood obesity. OBJECTIVE: To investigate whether the introduction of milk thickeners to bottle-fed infants between 3 and 6 months of age was associated with higher anthropometric measurements and indices at 1 and 4 years of age. METHODS: A population-based birth cohort study was conducted in 1993 in the urban area of Pelotas, Brazil. Information was obtained at birth, at 1, 3, 6, and 12 months, and at 4 years. Data were analyzed from the 596 children for whom information was available from all follow-up visits. The exposure of interest was the use of milk thickener (flour added to cow's milk) between the third and sixth months of life. The outcomes investigated were weight and length/height and the anthropometric indices weight-for-age, length/height-for-age, and weight-for-length/height z-scores at 1 and 4 years. RESULTS: The prevalence of use of milk thickener at any time between the third and sixth months was 44.6%. In the adjusted analysis, children who received milk thickener were, on average, 160 g heavier and 0.5 cm longer at I year than those who did not receive it. Weight-for-age and length-for-age z-scores were positively associated with use of milk thickener. No association was observed between this feeding practice and weight-for-length z-score. In the adjusted analysis, no effect of use of milk thickener on any of the anthropometric outcomes studied was observed at 4 years. CONCLUSIONS: No association was found between the use of milk thickeners and weight-for-length/height z-scores in the first and fourth years of life. Future studies in other contexts would be helpful to further test this hypothesis.     

A summary of national reports of foodborne outbreaks of Salmonella Heidelberg infections in the United States: clues for disease prevention

We analyzed national foodborne outbreak data from 1973 through 2001 to determine the proportion of Salmonella Heidelberg outbreaks caused by specific foods. Among 6633 outbreaks with known etiology, 184 (3%) were caused by Salmonella Heidelberg. A vehicle was identified in 101 outbreaks; at least 53 were poultry or egg-related. Three outbreaks were attributed to egg consumption, 17 to consumption of egg-containing foods, 25 to poultry, and 8 to foods containing poultry and eggs. Efforts to reduce illness due to Salmonella Heidelberg shouldensure that poultry and eggs are handled appropriately to minimize contamination and cross contamination.     

Cell death induced by serum deprivation in luteal cells involves the intrinsic pathway of apoptosis

The corpus luteum is a transient endocrine gland specializing in the production of progesterone. The regression of the corpus luteum involves an abrupt decline in its capacity for producing progesterone followed by its structural involution, which is associated with apoptosis of the luteal cells. An in vitro experimental approach is needed to study the molecular mechanisms underlying hormonal regulation of luteal cell death under defined experimental conditions. In this study, we investigated simian virus-40-transformed luteal cells to determine whether they can be driven to apoptosis and, if so, to define the intracellular pathway involved. Luteal cells were cultured in the presence or absence of fetal bovine serum for 24 or 48 h. Under serum starvation conditions, the luteal cells underwent growth arrest accompanied by cell death as evaluated by dye exclusion, and confirmed by two-color fluorescence cell viability/cytotoxicity assay. We next studied whether serum starvation-induced death of luteal cells occurred by apoptosis. Morphologic features of apoptosis were observed in cells stained with hematoxylin after being subjected to serum starvation for 48 h. The apoptotic nature was further confirmed by in situ 3'-end labeling and fragmentation of genomic DNA. Apoptosis of serum-deprived luteal cells was dependent upon caspase activation. Serum starvation induced cleavage of poly (ADP-ribose) polymerase (PARP), suggesting that caspase-3 had been activated under the stress of withdrawal of growth factors. This was confirmed by cleavage of full-length procaspase-3. Finally, the fact that serum starvation promoted the cleavage of full-length procaspase-9 and the decrease in the expression of endogenous Bid, a BH-3-only proapoptotic protein of the Bcl-2 family, indicates that the intrinsic (i.e., mitochondrial) pathway of apoptosis was activated. In summary, we have characterized an in vitro experimental model of luteal cell death that can be utilized to evaluate the role of hormones in apoptosis of luteal cells under defined culture conditions, and to study the mechanism of luteal regression.     

Combined atomic force microscopy and optical microscopy measurements as a method to investigate particle uptake by cells

We propose a combination of atomic force microscopy (AFM) and optical microscopy for the investigation of particle uptake by cells. Positively and negatively charged polymer microcapsules were chosen as model particles, because their interaction with cells had already been investigated in detail. AFM measurements allowed the recording of adhesion forces on a single-molecule level. Due to the micrometer size of the capsules, the number of ingested capsules could be counted by optical microscopy. The combination of both methods allowed combined measurement of the adhesion forces and the uptake rate for the same model particle. As a demonstration of this system, the correlation between the adhesion of positively or negatively charged polymer microcapsules onto cell surfaces and the uptake of these microcapsules by cells has been investigated for several cell lines. As is to be expected, we find a correlation between both processes, which is in agreement with adsorption-dependent uptake of the polymer microcapsules by cells.     

Increase over time in the prevalence of multiple antibiotic resistance among isolates of Listeria monocytogenes from poultry in Spain

The aim of this study was to determine and compare the antibiotic resistance profiles of Listeria monocytogenes isolates obtained from poultry in North-Western Spain in 1993 and 2006. The prevalence of Listeria spp. and L. monocytogenes was also investigated. A total of 202 samples were analysed (100 in 1993 and 102 in 2006). Samples taken in 1993 and 2006 showed a similar (P > 0.05) prevalence for both Listeria spp. (95.0% and 92.1%, respectively) and L. monocytogenes (32.0% and 24.5%). In both 1993 and 2006 the species most frequently detected was Listeria innocua, followed by L. monocytogenes. Other species isolated were Listeria welshimeri, Listeria grayi and Listeria ivanovii. L. monocytogenes isolates (68) were tested by disc diffusion assay for their resistance to 15 drugs currently used in veterinary and human therapy. All isolates displayed resistance to at least one antibiotic. Excluding nalidixic acid, to which most strains are intrinsically resistant, 37.2% of strains in 1993 and 96.0% in 2006 showed resistance to at least one antibiotic. Multi-resistance (resistance to two or more antibiotics) was less common in 1993 than in 2006 (18.6% and 84.0%, respectively; P < 0.001). The average number of antibiotics to which the strains were resistant was lower (P < 0.001) in 1993 (1.6) than in 2006 (4.2). An increase (P < 0.05) in the percentage of resistant strains was observed between 1993 and 2006 for six different drugs: gentamicin, streptomycin, neomycin, enrofloxacin, ciprofloxacin and furazolidone. In this research, the prevalence and the antibiotic susceptibility of L. monocytogenes in poultry samples from the same origin in North-Western Spain in the 1990s and the 2000s were compared for the first time. The increase in antibiotic resistance from 1993 to 2006 constitutes a matter for concern and confirms a general worldwide pattern among many groups of bacteria. The high prevalence of L. monocytogenes in poultry suggests the crucial role of food handlers in preventing listeriosis in consumers. Reducing the prevalence of L. monocytogenes in poultry and preventing the emergence or selection of antibiotic-resistant strains are also highlighted.     

Detection of Salmonella in Shellfish Using SYBR Green™ I-Based Real-Time Multiplexed PCR Assay Targeting invA and spvB

A SYBR Green? I-based real-time multiplexed PCR assay was developed targeting invA and spvB for the detection of Salmonella strains in shellfish after both hns and invA genes were identified in all Salmonella strains. Simultaneously, the 16S rRNA gene was used as a PCR internal amplification control (IAC). All 89 Salmonella strains tested in this study exhibited amplification of invA, whereas only 21 (23.6 %) were PCR positive for spvB. The sensitivity of detection of all three targeted genes was 1 ng, which is equivalent to approximately 10⁵ colony-forming unit (CFU) of Salmonella enterica. The analysis showed specific PCR products that were identified by reproducible melt temperature profiles (invA, 84.27?±?1.7 °C; spvB, 88.76?±?1.0 °C; and 16S rRNA gene, 87.16?±?0.8 °C).The sensitivity of detection was 10 pg purified DNA (invA) or 10⁵?CFU in 1 mL pure culture of S. enterica ATCC 14028. The above molecular detection method for Salmonella strains was successfully applied to the oyster homogenates (food matrix). An initial inoculum of 10⁶ and 10²?CFU Salmonella in 1 ml seeded oyster tissue homogenate was detected by multiplexed PCR for all three genes after 5 and 24 h of enrichment, respectively. Natural oysters isolated from Gulf of Mexico during the winter months exhibited negative PCR amplification results suggesting the absence of Salmonella. In contrast to conventional PCR, real-time multiplex PCR assay developed in this study is rapid and sensitive and will help Interstate Shellfish Sanitation Conference undertake appropriate measures to monitor Salmonella in oysters, thereby preventing disease outbreaks and consequently protecting consumer health.     

Study of the retention and release of n-hexanal incorporated into soy protein isolate–lipid composite films

This work deals with the study of the kinetic of aroma release, which had been previously incorporated into soy protein isolate (SPI)–lipid composite films. The aim was to determine the influence of type and amount of lipidic material on aroma (n-hexanal) release and retention, as well as the apparent diffusion coefficients. To carry out this study it have been employed SPI-based films containing two SPI:LIPID ratios (1:0.25 and 1:0.5), and two types of lipids, oleic acid (OA) and beeswax (BW), in OA:BW ratios 100:0, 70:30, 50:50, 30:70 and 0:100. The measurements were performed by a gas chromatography technique. The films that showed more retention were SPI:LIPID 1:0.5 100% BW and control film. Concerning release rate, films containing BW as unique lipid material gave the lowest aroma release rate. Apparent diffusion coefficients (D_app) of all films are in the same order of magnitude (10⁻¹⁵ m² s⁻¹). D_app decreases when BW increases in the film matrix and when oleic acid amount decreases. In conclusion, for encapsulating n-hexanal, SPI-BW films demonstrated the best performances, followed by control film (without lipids).     

Emulsifying and foaming capacity and emulsion and foam stability of sesame protein concentrates

This study examined the effects of oil concentration and pH on the emulsifying and foaming characteristics of sesame protein concentrate (SESPC). SESPC was obtained through a simplified process, and its properties were compared with those of a commercial soybean concentrate (SOYPC). The simplified process did not affect the functional characteristics of SESPC, which were often similar or superior to those of the SOYPC. The maximum emulsifying capacity of SESPC was 38% at an acidic and alkaline pH, while the maximum emulsifying capacity of SOYPC was 44% at the same pH. Emulsifying capacity increased significantly as oil concentration increased; in SESPC, this capacity increased from 7.8 to 60.0%, while in SOYPC it increased from 7.6 to 68.2%. The emulsion stability of SESPC was greater at an acidic pH (51%) than at an alkaline pH (45%); it was also higher than the emulsion stability of SOYPC. The maximum emulsion stability of SESPC (96%) was obtained at a sample concentration greater than 55 g L^− 1 and oil concentration lees than 550 g L^− 1 oil. Minimum (118.3%) and maximum (240%) levels of SESPC foaming capacity were higher than those obtained for SOYPC (92% as maximum). These findings show that SESPC may have potential use as raw matter in the food industry. At an extreme pH, SESPC continued to have important functional characteristics like emulsion stability, oil absorption and foaming capacity.     

Tissue-engineered fibrin scaffolds containing neural progenitors enhance functional recovery in a subacute model of SCI

Two recurring problems with stem/neural progenitor cell (NPC) transplantation therapies for spinal cord injury (SCI) are poor cell survival and uncontrolled cell differentiation. The current study evaluated the viability and differentiation of embryonic stem cell-derived neural progenitor cells (ESNPCs) transplanted within fibrin scaffolds containing growth factors (GFs) and a heparin-binding delivery system (HBDS) to enhance cell survival and direct differentiation into neurons. Mouse ESNPCs were generated from mouse embryonic stem cells (ESCs) using a 4-/4+ retinoic acid (RA) induction protocol that resulted in a population of cells that was 70% nestin positive NPCs. The ESNPCs were transplanted directly into a rat subacute dorsal hemisection lesion SCI model. ESNPCs were either encapsulated in a fibrin scaffold; encapsulated in fibrin containing the HBDS, neurotrophin-3 (NT-3) and platelet derived growth factor (PDGF-AA); or encapsulated in fibrin scaffolds with NT-3 and PDGF-AA without the HBDS. We report that the combination of GFs and fibrin scaffold (without HBDS) enhanced the total number of ESNPCs present in the treated spinal cords and increased the number of ESNPC-derived NeuN positive neurons 8 weeks after transplantation. All experimental groups treated with ESNPCs exhibited an increase in behavioral function 4 weeks after transplantation. In a subset of animals, the ESNPCs over-proliferated as evidenced by SSEA-1 positive/Ki67 positive ESCs found at 4 and 8 weeks. These results demonstrate the potential of tissue-engineered fibrin scaffolds to enhance the survival of NPCs and highlight the need to purify cell populations used in therapies for SCI.