Use of High Hydrostatic Pressure to Increase the Content of Xanthohumol in Beer Wort

During beer production, xanthohumol (XN) extracted from hop through wort boiling is largely converted into its isomeric flavanone, isoxanthohumol (IXN), due to the thermal treatment. XN has a great biological interest as a functional compound (being anti-carciogenic, antioxidant, anti-inflammatory, and anti-infective) and its loss leads to beers with very small amounts of XN and reduced functional properties. In this work, we studied the use of high-pressure treatments (HP; 100, 200, 250, 300, 400 and 500 MPa for 5 min and 250 and 400 MPa for 15 min), applied to previously boiled worts with a second hop dosage, as an extractive procedure, to produce XN-enriched beer worts. The results indicated that beer worts processed by HP showed higher levels of XN. The best results were obtained for 250 MPa, 5 min, resulting in an increase of 4-fold in XN, compared with beer worts produced only by boiling, and 2-fold compared with a method mimicking a recently proposed methodology also intended to improve XN in wort (called XAN method). Combinations of lower pressures with short pressurisation periods proved to be more efficient to increase the amount of XN in the wort. Moreover, HP-processed worts showed lower levels of IXN compared with samples produced by the mimicked XAN method. Physical–chemical characteristics of worts (pH, colour, bitterness and original extract) produced by HP, were similar to those produced only by boiling. These results clearly indicate the potential of using HP treatments to increase the XN content in beer wort, together with less isomerisation to IXN, and open promising possibilities to produce beers with higher amounts of XN, with potentially enhanced functional properties and health promoting properties.     

A two-scale Weibull approach to the failure of porous ceramic structures made by robocasting: Possibilities and limits

This paper introduces our approach to modeling the mechanical behavior of cellular ceramics, through the example of calcium phosphate scaffolds made by robocasting for bone–tissue engineering. The Weibull theory is used to deal with the scaffolds’ constitutive rods statistical failure, and the Sanchez-Palencia theory of periodic homogenization is used to link the rod- and scaffold-scales. Uniaxial compression of scaffolds and three-point bending of rods were performed to calibrate and validate the model. If calibration based on rod-scale data leads to over-conservative predictions of scaffold's properties (as rods’ successive failures are not taken into account), we show that, for a given rod diameter, calibration based on scaffold-scale data leads to very satisfactory predictions for a wide range of rod spacing, i.e. of scaffold porosity, as well as for different loading conditions. This work establishes the proposed model as a reliable tool for understanding and optimizing cellular ceramics’ mechanical properties.     

Optimisation of analytical methods for the characterisation of oranges,clementines and citrus hybrids cultivated in Spain on the basis of their composition in ascorbic acid,citric acid and major sugars

Three HPLC methods were optimised for the determination of citric acid, succinic acid and ascorbic acid using a photodiode array detector and fructose, glucose and sucrose using a refractive index in twenty eight citrus juices. The analysis was completed in <16 min. Two different harvests were taken into account for this study. For the season 2011, ascorbic acid content was comprised between 19.4 and 59 mg vitamin C/100 mL; meanwhile for the season 2012, the content was slightly higher for most of the samples ranging from 33.5 to 85.3 mg vitamin C/100 mL. Moreover, the citric acid content in orange juices ranged between 9.7 and 15.1 g L^?1, while for clementines the content was clearly lower (i.e. from 3.5 to 8.4 g L^?1). However, clementines showed the highest sucrose content with values near to 6 g/100 mL. Finally, a cluster analysis was applied to establish a classification of the citrus species.     

Atmospheric plasma spraying coatings from alumina–titania feedstock comprising bimodal particle size distributions

In this work, Al₂O₃–13 wt% TiO₂ submicron-nanostructured powders were deposited using atmospheric plasma spraying. The feedstocks were obtained by spray drying two starting suspensions of different solids content, prepared by adding nanosized TiO₂ and submicron-sized Al₂O₃ powders to water. The spray-dried granules were heat-treated to reduce their porosity and the powders were fully characterised in both untreated and thermally treated state. Comparison with two commercial feedstocks was carried out. Characterisation allowed a temperature for the thermal treatment to be chosen on the basis of the sprayability of the feedstock and the preservation as much as possible of the submicron-sized structure of the unfired agglomerates.Optimisation of the deposition conditions enabled the reconstituted powders to be successfully deposited, yielding coatings that were well bonded to the substrate. The coating microstructure, characterised by SEM, was mostly formed by a matrix of fully molten particles where the presence of semi-molten feedstock agglomerates was also observed.Moreover, microhardness, toughness, adhesion and tribological behaviours were determined, and the impact of the granule characteristics on these properties was studied. It was found that changing the feedstock characteristics allows controlling the coating quality and properties. In general, good mechanical properties were obtained using a feedstock comprising a binary mixture of submicrometric Al₂O₃ and nanometric TiO₂ particles in the spray-dried powder.     

Terahertz Emission from GaAs Films on Si(100) and Si(111) Substrates Grown by Molecular Beam Epitaxy

We report on the terahertz emission from femtosecond-laser-irradiated GaAs layers grown on Si(100) and Si(111) substrates. The results show that the terahertz emission from GaAs on Si is stronger than that of a semi-insulating bulk GaAs crystal. This increase is attributed to the strain field at the GaAs/Si interface. In the GaAs of the Si(100) sample, the stronger terahertz emission is observed compared with GaAs on Si(111). Moreover, the effect of changing the doping type of the Si substrate from n-type to semi-insulating was also studied and it was found that the terahertz emission intensity of GaAs on semi-insulating Si(100) is stronger than that of GaAs on n-type Si(100). Finally, strong terahertz emission from GaAs on semi-insulating Si(100) was observed not only in the reflection geometry but also in the transmission geometry. These results hold promise for new applications of terahertz optoelectronics.     

Determination of Heat Transfer During Gear Blank Quenching

This article presents experimental and numerical results for the quench of a gear blank in agitated and stagnant oil. The time history of temperature is determined with a whole-domain optimizer technique inverse solution method. This article offers a procedure to calculate the surface heat transfer on the quenched part by utilizing a straightforward minimization of an appropriate norm. The article presents 10 variations in setting up this inverse problem. The results indicate that dividing the boundary of the gear blank into four zones and assigning a fixed heat transfer coefficient or heat flux to each zone yields an average error of 40 K. This error can be reduced by either increasing the number of zones or by allowing the heat transfer coefficient or heat flux to vary within the zones. Of these possibilities, variation of heat transfer within the zones results in a greater reduction of the average error for the required level of computational effort.     

Effects of Hot Water Treatments on Antioxidant Enzymatic System in Reducing Flesh Browning of Persimmon

The flesh browning that appears during commercialization period is the main postharvest disorder that is limiting the market of “Rojo Brillante” persimmon in the Mediterranean area. Previous studies have suggested that mechanical damage suffered by the fruit during packing line operations is the trigger of this alteration when fruit is previously subjected to the required deastringecy treatment. In the present work, the effect of hot water treatments (HWTs) on flesh browning incidence of Rojo Brillante persimmon has been investigated. For that, fruits submitted to the commercial deastringency treatment were hot water treated at 45 °C for 30 min or 50 °C for 20 min and then subjected to different intensity of mechanical damage in packing line. Fruit bathed at 25 °C for 25 min and fruit hand-packed acted as control treatments. Our results confirmed that mechanical damage during packing is a decisive factor in the incidence of flesh browning, and this alteration is found to increase the damage intensity. HWTs significantly alleviated flesh browning disorder by affecting the antioxidative system enzymes; the activity of catalase and ascorbate peroxidase was increased by HWTs while the activity of peroxidases was reduced. No changes were observed in polyphenol oxidase and phenylalanine ammonia lyase activity. Therefore, the application of HWTs may be a useful postharvest technology to reduce flesh browning of persimmon induced by packing line operations.     

A cross-cultural analysis of the effect of language on perceived risk online

This paper investigates whether perceived risk online is affected by the language in which a user browses a given website. In order to achieve this objective and test the proposed hypotheses, a 2 × 2 between-subjects experimental design was chosen, using two independent variables with two levels each, namely: culture (Spanish vs. British) and processing language (Spanish vs. English). The final sample comprised 491 individuals (264 Spanish and 227 British). Half the sample browsed in their mother tongue, and the other half in a second language. The results showed that Spanish users perceive less risk when browsing in English than in Spanish, while for the British there was no difference, in terms of perceived risk, between browsing in Spanish or English. Another interesting finding is the moderating effect of message involvement on the processing of information from the website, and thus its effect on the user’s perception of risk.     

Nonenzymatic browning of selected fruit juices affected by D-galacturonic acid

This work studies the effect of d ‐galacturonic acid (AGA) on the non‐enzymatic browning of three types of clarified concentrated fruit juices (apple, pear and peach). It was observed that the presence of AGA increases the browning of juices. This was evaluated by the evolution of the absorbance at 420 nm (A₄₂₀) with the treatment time that these juices show. The evolution at A₄₂₀ over time was fitted to first‐order kinetics and it was observed that the kinetic constant values increased with both the increase in the AGA content and the rise in the treatment. The effect of the temperature treatment on the non‐enzymatic browning of these juices was quantified by fitting the variation of the kinetic constants with the Arrehnius equation, thus obtaining the corresponding activation energies. In the case of apple juice, it was observed that for the increase in AGA content the activation energy increases considerably, while for the pear and peach juices, a slight increase of the activation energy was observed with the increase in AGA.