Beer Clarification by Novel Ceramic Hollow‐Fiber Membranes: Effect of Pore Size on Product Quality

In this work, the crossflow microfiltration performance of rough beer samples was assessed using ceramic hollow‐fiber (HF) membrane modules with a nominal pore size ranging from 0.2 to 1.4 μm. Under constant operating conditions (that is, transmembrane pressure difference, TMP = 2.35 bar; feed superficial velocity, v_S = 2.5 m/s; temperature, T = 10 °C), quite small steady‐state permeation fluxes (J^*) of 32 or 37 L/m²/h were achieved using the 0.2‐ or 0.5‐μm symmetric membrane modules. Both permeates exhibited turbidity <1 EBC unit, but a significant reduction in density, viscosity, color, extract, and foam half‐life with respect to their corresponding retentates. The 0.8‐μm asymmetric membrane module might be selected, its corresponding permeate having quite a good turbidity and medium reduction in the aforementioned beer quality parameters. Moreover, it exhibited J^* values of the same order of magnitude of those claimed for the polyethersulfone HF membrane modules currently commercialized. The 1.4‐μm asymmetric membrane module yielded quite a high steady‐state permeation flux (196 ± 38 L/m²/h), and a minimum decline in permeate quality parameters, except for the high levels of turbidity at room temperature and chill haze. In the circumstances, such a membrane module might be regarded as a real valid alternative to conventional powder filters on condition that the resulting permeate were submitted to a final finishing step using 0.45‐ or 0.65‐μm microbially rated membrane cartridges prior to aseptic bottling. A novel combined beer clarification process was thus outlined.     

Shape-Resonant Superconductivity in Nanofilms: from Weak to Strong Coupling

Ultrathin superconductors of different materials are becoming a powerful platform to find mechanisms for enhancement of superconductivity, exploiting shape resonances in different superconducting properties. Here, we evaluate the superconducting gap and its spatial profile, the multiple gap components, and the chemical potential, of generic superconducting nanofilms, considering the pairing attraction and its energy scale as tunable parameters, from weak to strong coupling, at fixed electron density. Superconducting properties are evaluated at mean field level as a function of the thickness of the nanofilm, in order to characterize the shape resonances in the superconducting gap. We find that the most pronounced shape resonances are generated for weakly coupled superconductors, while approaching the strong coupling regime the shape resonances are rounded by a mixing of the subbands due to the large energy gaps extending over large energy scales. Finally, we find that the spatial profile, transverse to the nanofilm, of the superconducting gap acquires a flat behavior in the shape resonance region, indicating that a robust and uniform multigap superconducting state can arise at resonance.     

A spatial decomposition of the shift-share components of labour productivity inequality in Italy

This paper explores the components of aggregate labour productivity inequality between Italian regions from 2000 to 2013. The Gini index of inequality in aggregate labour productivity is decomposed, showing the extent to which sector productivity differentials and differences in industry-mix contribute to regional productivity inequality. In addition, the contribution of the interaction between differences in industry-mix and sector productivity differentials is revealed by the decomposition. Each of these contributions to inequality is measured by considering the spatial dimension of regional inequality, since the contributions of inequality between non-neighbouring regions and inequality between neighbouring regions are separated.     

Eumelanin for nature‐inspired UV‐absorption enhancement of plastics

In the human body, the black‐brown biopigment eumelanin blocks harmful ultraviolet (UV) radiation. In the plastics industry, additives are often added to polymers to increase their UV‐absorption properties. We herein report an assessment of the biopigment eumelanin as a nature‐inspired additive for plastics to enhance their UV absorption. Since eumelanin is produced by natural sources and is nontoxic, it is an interesting candidate in the field of sustainable plastic additives. In this work, the eumelanin‐containing films of commercial ethylene–vinyl acetate copolymer, a plastic used for packaging applications, were obtained by melt compounding and compression molding. The biopigment dispersion in the films was improved by means of the melanin free acid treatment. It was observed that eumelanin amounts as low as 0.8 wt% caused an increase of the UV absorption, up to one order of magnitude in the UVA range. We also evaluated the effect of eumelanin on the thermal stability and photostability of the films: the biopigment proved to be double‐edged, working both as UV‐absorption enhancer and photo‐prooxidant, as thermogravimetric analysis and infrared spectroscopy revealed. © 2019 Society of Chemical Industry     

Hyperbaric storage at and above room temperature of a highly perishable food

Hyperbaric storage at naturally variable room temperature (RT) conditions (18–21 °C) and above (30 °C) was evaluated as a possible new food preservation method, regardless of temperature. Preservation of watermelon juice (used as a case study of a highly perishable food) at RT and 5 °C at atmospheric pressure was compared to preservation under 100 MPa at RT. After 8 h of hyperbaric storage at 100 MPa, the initial microbial loads of the watermelon juice were reduced by 1 log unit for total aerobic mesophiles, and 1–2 log units for Enterobacteriaceae and yeasts and moulds, to levels of about 3 log units for the former and below the detection limit for the latter, and remained thereafter unchanged up to 60 h. Similar results were obtained at 30 °C at 100 MPa after 8 h. At atmospheric pressure at RT (24 h) and 30 °C (8 h), microbial levels were already above quantification limits and unacceptable for consumption. Furthermore, pressure attenuated the increase in titratable acidity verified at atmospheric pressure, but caused higher colour changes, especially a higher lightness and a lower browning degree. Post-hyperbaric storage at 5 °C revealed an extended shelf life, as an additional benefit of hyperbaric storage. These results show that hyperbaric storage is a very promising food preservation methodology.     

Multifunctional TiO2 coatings for Cultural Heritage

Environmental pollution arising from industrial implants and urban factors is constantly increasing, causing aesthetical and durability concerns to urban structures exposed to the atmosphere.     

Nuclear DNA barcodes for cod identification in mildly-treated and processed food products

Gadoids are a group of fish with historical importance in the fishing industry. The high demand for cod is one of the reasons why cod products are often mislabelled, and numerous observations have been made on the replacement of Atlantic cod (Gadus morhua) by cheaper species or its illegal capture in contravention of fish quotas. Fish species identification is traditionally based on morphological features, but this may be difficult in case of heat-treated or processed products, or where the species look similar, as in the Gadoid group. DNA-based approaches (using either nuclear or mitochondrial DNA) are most commonly used in this case, due to their high specificity and to the high resilience of the target molecules to food processing techniques. In this article, we identified, using an automated screening approach, novel barcode regions and their associated primers in the nuclear genome, to be used for the efficient identification of Gadoids. The barcode regions were tested on official and commercial samples, raw or mildly treated products, like frozen, or salted, as well as pre-cooked complex mixtures and processed samples, using next-generation sequencing (NGS) technique. The method proposed could complement existing fish identification strategies in establishing an efficient framework to detect and prevent frauds along the food chain.     

Primary particle movement and change of property of cast iron by centrifugal effect in semi-solid processing

The particle distribution in semi-solid slurry under centrifugal field was simulated and the main factors such as fraction of solid, rotation speed, and holding time effecting the particle distributions are discussed. The simulation results showed that primary particles rich zone is produced in radially outer area and these results are in good agreement with the experiment. The centrifugal effect produces the primary particles distribution along the radial direction. Denser particles are concentrated in outside than inner side. For high fraction of solid samples, ‘wall’ appear in the middle of samples because of high viscosity region making particle difficult to move. Longer holding time gives denser primary particles concentrated more in outside than inner side. Higher rotation speed gives increased gradient of hardness in the radial direction. It is due to that number of primary austenite at inner side at higher rotation speed is less than that at lower rotation one. At higher rotation speed, ledeburite forms more at inner side of specimen than at the other one. It is also shown that semi-solid processing at lower fraction of solid gives higher hardness because smaller number of primary austenite, namely more ledeburite forms in microstructure. The present study gives useful information on producing material with locally changing property by semi-solid processing.