Phenolic content and antioxidant activity of tortillas produced from pigmented maize processed by conventional nixtamalization or extrusion cooking

The effects of traditional nixtamalization and extrusion cooking on total phenolics, ferulic acid, anthocyanins and Oxygen Radical Absorbance Capacity (ORAC) of Mexican pigmented (blue and red) and commercial (white and yellow) maize processed into tortillas were investigated. Tortillas prepared from extruded flours retained between 76.2–93.9% and 58–96.7% of total phenolics and total ferulic acid (TFA) respectively, compared to 50.5–75.7% and 19.6–55.8% assayed in traditional tortillas. Approximately 97–99% of TFA in raw kernels and their tortillas was in its bound form. The retention of TFA in traditional tortillas was significantly lower compared to tortillas from extruded flours. Traditional tortillas contained more free ferulic acid compared to tortillas produced from extruded flours indicating that the first process liberated bound ferulic acid with cell walls more efficiently. Blue maize lost more than 55% of the anthocyanins when processed into extruded or traditional tortillas. Approximately 68–92% of the ORAC associated with raw kernels or their tortillas was due to bound compounds. Traditional and extruded tortillas lost 16.4–52.4% and 6.8–24.8%, respectively, of the total ORAC associated with raw grains. Results clearly indicate that the proposed lime-cooking extrusion strategy was instrumental in retaining higher levels of phytochemicals, particularly ferulic acid, and antioxidants in all tortillas.     

Effect of high-pressure treatment on rheological,thermal and structural changes in Basmati rice flour slurry

Rheological, thermal and structural changes in high pressure (HP) treated Basmati rice flour dispersions were studied as function of pressure level (350–650 MPa), slurry concentration (with 1:5, 1:3 and 1:2 flour-to-water ratios) and holding time (7.5–15 min). Rice flour dispersions exhibited a gradual liquid–solid gel transformation as they gelatinized and/or denatured and behaved as viscoelastic fluid following HP treatment. Mechanical strength (G′) of pressurized gel increased with applied pressure and rice concentration. Differential scanning calorimeter (DSC) thermograms of rice slurry measured after pressure treatment indicated a reduction in peak enthalpy in proportion with the extent of gelatinization and/or denaturation of starch and proteins. Pressure-treated rice samples had a progressively lower gelatinization temperature. A 15 min pressure treatment at 550 MPa was found sufficient to complete gelatinization of protein free isolated rice starch while the slurry required 650 MPa. The presence of proteins might have been responsible for the slower starch gelatinization in the rice slurry during pressure treatment. The sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Fourier-transform infrared (FTIR) spectroscopy results indicated some minor changes in protein subunits and secondary structure of rice protein. This study has provided complementary information on pressure-induced changes in physical (thermal stability, overall structure) and molecular level (secondary structure) of rice protein.     

Asymmetric coevolutionary networks facilitate biodiversity maintenance

The mutualistic interactions between plants and their pollinators or seed dispersers have played a major role in the maintenance of Earth's biodiversity. To investigate how coevolutionary interactions are shaped within species-rich communities, we characterized the architecture of an array of quantitative, mutualistic networks spanning a broad geographic range. These coevolutionary networks are highly asymmetric, so that if a plant species depends strongly on an animal species, the animal depends weakly on the plant. By using a simple dynamical model, we showed that asymmetries inherent in coevolutionary networks may enhance long-term coexistence and facilitate biodiversity maintenance.     

<Emphasis Type="Italic">Lupinus albus</Emphasis> Conglutin Gamma Modifies the Gene Expressions of Enzymes Involved in Glucose Hepatic Production <Emphasis Type="Italic">In Vivo</Emphasis>

Lupinus albus seeds contain conglutin gamma (Cγ) protein, which exerts a hypoglycemic effect and positively modifies proteins involved in glucose homeostasis. Cγ could potentially be used to manage patients with impaired glucose metabolism, but there remains a need to evaluate its effects on hepatic glucose production. The present study aimed to analyze G6pc, Fbp1, and Pck1 gene expressions in two experimental animal models of impaired glucose metabolism. We also evaluated hepatic and renal tissue integrity following Cγ treatment. To generate an insulin resistance model, male Wistar rats were provided 30% sucrose solution ad libitum for 20 weeks. To generate a type 2 diabetes model (STZ), five-day-old rats were intraperitoneally injected with streptozotocin (150 mg/kg). Each animal model was randomized into three subgroups that received the following oral treatments daily for one week: 0.9% w/v NaCl (vehicle; IR-Ctrl and STZ-Ctrl); metformin 300 mg/kg (IR-Met and STZ-Met); and Cγ 150 mg/kg (IR-Cγ and STZ-Cγ). Biochemical parameters were assessed pre- and post-treatment using colorimetric or enzymatic methods. We also performed histological analysis of hepatic and renal tissue. G6pc, Fbp1, and Pck1 gene expressions were quantified using real-time PCR. No histological changes were observed in any group. Post-treatment G6pc gene expression was decreased in the IR-Cγ and STZ-Cγ groups. Post-treatment Fbp1 and Pck1 gene expressions were reduced in the IR-Cγ group but increased in STZ-Cγ animals. Overall, these findings suggest that Cγ is involved in reducing hepatic glucose production, mainly through G6pc inhibition in impaired glucose metabolism disorders.     

Enzyme Bioprospection of Marine-Derived Actinobacteria from the Chilean Coast and New Insight in the Mechanism of Keratin Degradation in Streptomyces sp. G11C

Marine actinobacteria are viewed as a promising source of enzymes with potential technological applications. They contribute to the turnover of complex biopolymers, such as pectin, lignocellulose, chitin, and keratin, being able to secrete a wide variety of extracellular enzymes. Among these, keratinases are a valuable alternative for recycling keratin-rich waste, which is generated in large quantities by the poultry industry. In this work, we explored the biocatalytic potential of 75 marine-derived actinobacterial strains, focusing mainly on the search for keratinases. A major part of the strains secreted industrially important enzymes, such as proteases, lipases, cellulases, amylases, and keratinases. Among these, we identified two streptomycete strains that presented great potential for recycling keratin wastes—Streptomyces sp. CHA1 and Streptomyces sp. G11C. Substrate concentration, incubation temperature, and, to a lesser extent, inoculum size were found to be important parameters that influenced the production of keratinolytic enzymes in both strains. In addition, proteomic analysis of culture broths from Streptomyces sp. G11C on turkey feathers showed a high abundance and diversity of peptidases, belonging mainly to the serine and metallo-superfamilies. Two proteases from families S08 and M06 were highly expressed. These results contributed to elucidate the mechanism of keratin degradation mediated by streptomycetes.     

Chemical Characterization and Release of Polyphenols from Pecan Nut Shell [<Emphasis Type="Italic">Carya illinoinensis</Emphasis> (Wangenh) C. Koch] in Zein Microparticles for Bioactive Applications

The pecan nut [Carya illinoinensis (Wangenh) C. Koch] is a natural source of polyphenols with antioxidant properties. In this study, the encapsulation of aqueous and hydroalcoholic extracts of pecan nut shell were evaluated for the release of bioactive compounds and antioxidant potential in order to explore food applications using zein as encapsulating agent. The extracts showed high contents of total phenolics, condensed tannins and high antioxidant activity. Concentrations of proanthocyanidins were 9-fold higher in hydroalcoholic extracts. The LC-DAD analysis showed that catechins were the major phenolic compounds in samples, with epigallocatechin levels up to 138.62 mg mL^?1. Zein microparticles loaded with aqueous extract released 2.3 times more phenolic compounds than the hydroalcoholic extracts and the DSC thermograms showed that extracts of pecan nut shell remained thermally stable up to 240 °C. The zein microcapsules obtained in this study were efficiently encapsulated and represent an interesting additive due its high antioxidant capacity, physicochemical characteristics and morphology. The use of zein microparticles combined with natural extracts constitute a step forward in the improvement of current technology for delivering phenolic compounds with applications in functional foods and nutraceuticals.     

The cell and molecular basis of mechanical, cold, and inflammatory pain

Peripheral pain pathways are activated by a range of stimuli. We used diphtheria toxin to kill all mouse postmitotic sensory neurons expressing the sodium channel Nav1.8. Mice showed normal motor activity and low-threshold mechanical and acute noxious heat responses but did not respond to noxious mechanical pressure or cold. They also showed a loss of enhanced pain responses and spontaneous pain behavior upon treatment with inflammatory insults. In contrast, nerve injury led to heightened pain sensitivity to thermal and mechanical stimuli indistinguishable from that seen with normal littermates. Pain behavior correlates well with central input from sensory neurons measured electrophysiologically in vivo. These data demonstrate that Na(v)1.8-expressing neurons are essential for mechanical, cold, and inflammatory pain but not for neuropathic pain or heat sensing.     

Effects of no‐take area size and age of marine protected areas on fisheries yields: a meta‐analytical approach

Marine protected areas (MPAs) are often promoted as tools for biodiversity conservation as well as for fisheries management. Despite increasing evidence of their usefulness, questions remain regarding the optimal design of MPAs, in particular concerning their function as fisheries management tools, for which empirical studies are still lacking. Using 28 data sets from seven MPAs in Southern Europe, we developed a meta‐analytical approach to investigate the effects of protection on adjacent fisheries and asking how these effects are influenced by MPA size and age. Southern European MPAs showed clear effects on the surrounding fisheries, on the ‘catch per unit effort’ (CPUE) of target species, but especially on the CPUE of the marketable catch. These effects depended on the time of protection and on the size of the no‐take area. CPUE of both target species and the marketable catch increased gradually by 2–4% per year over a long time period (at least 30 years). The influence of the size of the no‐take area appeared to be more complex. The catch rates of the entire fishery in and around the MPA were higher when the no‐take areas were smaller. Conversely, catch rates of selected fisheries that were expected to benefit most from protection increased when the no‐take area was larger. Our results emphasize the importance of MPA size on its export functions and suggest that an adequate, often extended, time frame be used for the management and the evaluation of effectiveness of MPAs.