Use of molecular methods to characterize the bacterial community and to monitor different native starter cultures throughout the ripening of Galician chorizo

The development of Lactobacillus and Staphylococcus strains used as starter cultures throughout the ripening of Galician chorizo, a traditional dry fermented sausage from the north-west of Spain, was monitored combining different molecular-based techniques. The bacterial diversity occurring in the inoculated sausages at the beginning and the end of the ripening was also studied and compared to the indigenous population in an uninoculated control batch.     

Monitoring of virgin olive oil volatile compounds evolution during olive malaxation by an array of metal oxide sensors

In addition to the sanitary aspects of production and the genetic and/or geographic origin of the drupes olive malaxation is a critical control point of virgin olive oil (VOO) production from a qualitative point of view. In particular the sensory peculiarities of malaxation are determined by the presence of C₆ and C₅ aldehydes and alcohols in the VOO head space due to lipoxygenase activity. On-line monitoring of the evolution of these substances during VOO processing could be very useful for defining the operative conditions of malaxation (i.e. time and temperature) in order to improve the VOO sensory quality according to product type.     

Using mild heat treatment to improve the bioactive related compounds on fresh-cut green bell peppers

Bioactive related compounds of fresh-cut green bell peppers ( Capsicum annuum, L.) exposed to water immersion at 55 °C and 60 °C per 180 s were evaluated during storage. Their sensorial and microbial quality, acidity, sugar and chlorophyll content were also determined. Beneficial effects on sensorial attributes were observed in treated peppers with longer shelf life than in non-treated ones (5 days at 4 °C, 2 days at 10 °C). At the end of storage at 4 °C, phenols increased to 11% and quercetin and antioxidant capacity were retained, but in control peppers ascorbic acid dropped 16%. At 10 °C, there was no change in phenols; quercetin, ascorbic acid and antioxidant activity decreased (15%, 13% and 10% respectively) in treated peppers. Changes were more noticeable in non-treated products (phenols increased 21%, ascorbic acid decreased 28% and antioxidant activity 20%). Mild heat treatments applied to fresh-cut peppers seemed to preserve some of their bioactive compounds during storage.     

Insights into the physicochemical properties of coffee oil

The lipid fraction of roasted coffee is an interesting ingredient that could be used in a large number of food formulations. Coffee oil has peculiar flavouring as well as nutraceutical characteristics. The feasibility of the use of coffee oil as ingredient greatly depends not only on its chemical characteristics but also on its physical properties. The crystallisation and melting properties of the coffee oil extracted from Arabica roasted coffee powder were determined by using synchrotron X‐ray diffraction coupled with differential scanning calorimetry. The fatty acid composition and the flavour profile were also assessed by using GC and GC‐MS analyses, respectively. The main fatty acids found in coffee oil are linoleic and palmitic acid. Significant amounts of stearic and oleic acid are also present. These chemical characteristics are linked to the phase transition behaviour. The crystallisation of coffee oil occurs at 6.5 ± 0.3 °C, independently of the cooling rate applied (from 0.5 to 10 °C/min). A unique crystalline structure was identified: a double chain length (2L) β' structure (55.29 Å). The sole formation of the β' form indicates that this metastable crystal is the only one that one should expect in foods containing coffee oil stored below 7 °C.     

Accurately Measuring Denial of Service in Simulation and Testbed Experiments

Researchers in the denial-of-service (DoS) field lack accurate, quantitative, and versatile metrics to measure service denial in simulation and testbed experiments. Without such metrics, it is impossible to measure severity of various attacks, quantify success of proposed defenses, and compare their performance. Existing DoS metrics equate service denial with slow communication, low throughput, high resource utilization, and high loss rate. These metrics are not versatile because they fail to monitor all traffic parameters that signal service degradation. They are not quantitative because they fail to specify exact ranges of parameter values that correspond to good or poor service quality. Finally, they are not accurate since they were not proven to correspond to human perception of service denial. We propose several DoS impact metrics that measure the quality of service experienced by users during an attack. Our metrics are quantitative: they map QoS requirements for several applications into measurable traffic parameters with acceptable, scientifically determined thresholds. They are versatile: they apply to a wide range of attack scenarios, which we demonstrate via testbed experiments and simulations. We also prove metrics' accuracy through testing with human users.     

Effects of priming with multi-walled carbon nanotubes on seed physiological characteristics of Hopbush (Dodonaeaviscosa L.) under drought stress

This paper reports the effects of different dosages of multi-walled carbon nanotubes (MWCNTs) on seed germination of hopbush, a medicinal multipurpose plant. After nano-priming and drying under room temperature, the seeds were placed in a germinator under 20 °C constant temperature and 65% relative humidity with a photoperiodic regime of 16 h light/8 h dark at 1000 lux fluorescent light. The results show that MWCNTs can dramatically improve seed germination percentage, mean germination time (MGT), root and stem lengths, as well as fresh and dry weights of root and stem. When no drought stress was applied, germination percentage of 10 and 200 mg/l nano carbon treatments was found to be 100%, and MGT in all the studied treatments had a marked decrease as compared to that of the control counterparts. The best results were gained at zero osmotic pressure, in which the effect of CNTs treatment on the mentioned traits was maximal at 30 mg/l. Increasing the level of drought stress revealed that 50 and 100 mg/l dosages of MWCNTs could more favourably affect both the hopbush growth parameters and seed germination. Therefore, nano-priming with carbon tubes can be recommended for enhancing seed germination and plant growth in work on afforestation with hopbush, an evergreen shrub suitable for desert conditions.     

Hedonic ratings and consumption of school lunch among preschool children

Hedonic ratings of lunch items belonging to 20 school meals were collected from 71 children, 4 to 5 years old, over 2 months. During the subsequent lunch, the leftovers of each individual and menu item were recorded. The most preferred dishes were second courses (mainly based on meat or fish) and the least preferred dishes were vegetables. For all dishes, hedonic ratings predicted the amount uneaten (r = −0.96). Ratings of parents who completed a questionnaire on their children’s preferences also predicted successfully the amount uneaten (r = −.91). The more frequently a lunch item was served at home, the less were the leftovers, but the predictive equation for vegetables vs. other items were clearly different. A composite hedonic response index (HRI), based on ratings of all lunch items predicted low waste index (WI). In conclusion, hedonic ratings of 4–5-year-old children were a valid and highly predictive measure of consumption. Low and variable ratings of vegetable dishes raise the question on how vegetables should be served to encourage their consumption in young children.     

Mechanical properties of functionalized SEBS based inorganic hybrid materials

Summary Functional triblock copolymer [polystyrene-b-poly(ethylene-ran-butylene)-b-polystyrene] or SEBS elastomer was used to synthesize flexible organic-inorganic hybrid materials. Modification of elastomer was first achieved via nitration to produce nitrofunctionalized copolymer and its subsequent reduction forming aminofunctionalized copolymer. IR, ¹H NMR and ¹³C NMR spectroscopic analyses provided an evidence of their modified structures. Modified SEBS based hybrid materials were then prepared through solution intercalation technique using layered silicates and in-situ polymerization of metal alkoxides via sol-gel process. In the first attempt, hybrids were prepared by the reinforcement of aminofunctionalized SEBS with organophilic montmorillonite to establish compatibility between organic matrix and inorganic phase. Reinforcement of the modified copolymer was secondly achieved by hydrolytic condensation of tetraethoxysilane using 3-glycidyloxypropyl trimethoxysilane (as a coupling agent) yielding hybrid materials. The chemical interactions between the organic polymer chains and the inorganic networks produced in-situ led to better properties of modified elastomer. Mechanical properties of thin transparent films of these hybrids were measured. Tensile strength of hybrids shows a considerable improvement over pure SEBS as well as aminofunctionalized copolymer in all the systems, which shows an increased interfacial interaction between organic and inorganic phases.     

Growth kinetics of Rhizopus formosa MUCL 28422 on raw cassava flour in solid state fermentation

Solid state fermentations were carried out using a strain of Rhizopus formosa MUCL 28422 for its ability to grow on raw cassava. Optimal substrate composition, as estimated by surface response design experiments, was 10% each of cassava bagasse and soybean flour and 80% cassava flour. Optimal fermentation conditions were: temperature 32 °C, initial pH and moisture of the substrate 6.5 and 64%, respectively, and inoculum size 10⁶‐spores g⁻¹ dry matter. These conditions were employed for studying the kinetics of the biotransformation of cassava flour using Oxygen Uptake Rate (OUR) and Carbon dioxide Evolution Rate (CER) during the process. The respiratory quotient was ∼1, corresponding to an aerobic process in the first 24–26 h. Sporulation started after 26 h of fermentation when the respiratory quotient showed a trend to increase up to ∼6. Biomass estimation, based on oxygen consumption (Y_x/o) gave a value of 0.531 g biomass g⁻¹ O₂ consumed and the maintenance coefficient (m) was of the order of 0.068 g O₂ consumed g⁻¹ biomass h⁻¹. The corresponding value for the specific growth rate (µ) was 0.16 h⁻¹. © 1999 Society of Chemical Industry     

The Role of the pH in the Impregnation of Spherical Mesoporous Silica Particles with L-Arginine Aqueous Solutions

In the context of the development of carriers for amino acids delivery, Spherical Mesoporous Silica Particles (SMSP), characterized by particles size ranging from 0.15 µm to 0.80 µm and average pore diameter of 2.4 nm, were synthesised and loaded with L-arginine (ARG), a basic amino acid involved in several physiological processes. The loading was performed using water as a solvent through the wet impregnation method (with a final arginine content of 9.1% w/w). The material was characterized before and after impregnation by means of X-Ray Diffraction (XRD), nitrogen sorption analysis, Field Emission Scanning Electron Microscopy (FESEM) and Fourier Transform Infrared (FT-IR) spectroscopy. SMSP are shown to suffer degradation upon impregnation, which dramatically affects their porosity. To elucidate the role of the pH of the ARG impregnating solution (originally set at pH ≈ 11) on SMSP degradation, the loading was performed under different pH conditions (5 and 9) keeping constant the ARG concentration. The impregnation performed with acidic solution did not modify the carrier. All samples displayed ARG in amorphous form: zwitterionic species were present in SMSP impregnated at basic pH whereas positive protonated species in that impregnated at acidic pH.