170,163 research outputs found
Capabilities, sustainability, and innovation in mining value chains
No full textThe original research presented in this Special Section analyzes different aspects of the potential offered to mining firms in developing countries by new demands for solutions to face environmental, social and technological challenges. The evidence is drawn from extensive fieldworks and comparative econometric research on Latin America, and suggests that the existing opportunities will need to be pursued with firm-level efforts and active regulatory and innovation policies
Ohmic heating of basil-based sauces: Influence of the electric field strength on the electrical conductivity
No full textThe Moderate Electric Field (MEF) processing of foods consists in the application of an electric potential gradient (ΔV/L) ranging from 1 to 1000 V/cm on a food item (homogeneous or heterogeneous) placed between two electrodes, its main effect being the food heating due to the dissipation of a part of the electric energy into heat within the food item. The heating performances of such a system depend on several process and system parameters, including the applied ΔV/L, the food electrical conductivity, and its thermo-physical properties. In this study, the effects due to the salt composition and to the applied ΔV/L to a heterogeneous food (constituted by a basil-based sauce, mainly fibers dispersed in a slightly salted water-oil emulsion) treated in a custom MEF system on the food heating rate are investigated. The samples were prepared at different salinities (3.25, 1.63, 0.86 and 0.43% w/w respectively). In the explored range of compositions, the heating rate increased linearly with the square power of applied ΔV/L. A slight linearity deviation above 55°C was observed for the basil-based sauce at 1.63% and 5.20 V/cm, associated with bubble formation within the ohmic system and the electrolytic reactions occurring at the electrode-solution interface during the MEF heating process. The salt content as well as the ratio between water and oil in the sample formulation played a crucial role in determining the thermo-electrical behavior of the basil-based sauce samples. Samples with salinity of 1.63%, compared to samples at 3.25%, exhibited a higher electrical conductivity, being due to a minor concentration of the non-conductive phase (namely the oil phase as well as the dispersed vegetable fibers into the solution) that exerts a major degree of electrical insulation. As the salinity decreases from 1.63% to 0.43%, samples were characterized by lower electrical conductivities, being due to a reduced ionic mobility when the salt contained into the sample is drastically reduced
Monitoring of Ocrhatoxin A (OTA) adsorbing Saccharomyces cerevisiae strains during fermentation of must from botrytized grapes.
No full textEvaluation of different spray-drying conditions on the viability of wine yeast Saccharomyces cerevisiae LM52”
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Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Development of polyethylene films for food packaging activated with a foodgrade antilisterial bacteriocin
No full textFood packaging can be defined ‘‘functional packaging’’when a material and/or an accessory are used to improve the generic food protection of traditional food packaging. In the active packaging there is an interaction between package and food, implying a gas modification of headspace and/or a release of antimicrobial, antioxidant or other substances that improve food quality. Therefore, the final purposes of functional packaging are long time protection and safety of food as well as increase of appreciationand satisfaction of the consumers. Research on active packaging is already aiming the development of films capable to exercise an antimicrobial effect on food and drinks. In this study the antimicrobial effect of active polyethylene films was evaluated against Listeria monocytogenes. The film was made active by using the anti-listerial bacteriocin 32Y by Lactobacillus curvatus with three different procedures: soaking, coating and incorporation. While the soaking and coating treatments led to anti-listerial activity, no growth inhibition of the indicator strain Listeria monocytogenes OH was observed when the bacteriocin was incorporated in the polyethylene film. The antimicrobialactivity of the soaked and coated films was also tested in experiments of food packaging involving pork steak and ground beef contaminated by Listeria monocytogenes OH at roughly 103 cfu per cm2 and gram, respectively.The results of the challenge tests showed the highest antimicrobial activity after 24 hours at 4°C, with a decrease of about 1 Log of the Listeria monocytogenes population. Finally, experiments of migration of the coated bacteriocin in water were also performed resulting in a slow release of the antimicrobial substance
Studio delle popolazioni microbiche della �Soppressata del Vallo di Diano�, un insaccato carneo fermentato della Campania
No full textSebbene molti insaccati fermentati siano ormai prodotti a livello industriale, in Italia esistono ancora delle regioni in cui questi alimenti sono preparati seguendo metodiche tradizionali, che non prevedono l’utilizzo di colture starter. In particolare, la Campania è una delle regioni in cui è possibile trovare ancora delle piccole aziende produttrici di un tipo di insaccato tradizionale denominato “soppressata”, molto apprezzato sul mercato locale per le sue peculiari caratteristiche organolettiche. Lo studio dell’ecologia microbica di un prodotto fermentato è fondamentale per comprendere le specie realmente coinvolte nel processo fermentativo e per selezionare, nell’ambito di esse, gli specifici ceppi idonei alla formulazione di appropriate colture starter. Il primo scopo del presente lavoro, pertanto, è stato quello di identificare le principali popolazioni microbiche presenti al termine del processo fermentativo in campioni di soppressata del Vallo di Diano, mediante l’applicazione della tecnica PCR-DGGE in associazione con metodiche classiche di conteggio microbico. In tutti i campioni è stata osservata una netta dominanza di batteri lattici, compresi tra 1,4x106 e 3,2x109 UFC/g, e di stafilococchi, compresi tra 2,4x104 e 3,4x107 UFC/g. L’analisi PCRDGGE è stata condotta attraverso estrazione diretta del DNA da ciascun campione alimentare e da bulk cellulari ottenuti raccogliendo l’intero contenuto delle piastre contabili impiegate per il conteggio delle differenti popolazioni microbiche. In seguito al sequenziamento dei frammenti DGGE, le specie rinvenute maggiormente sono state Lactobacillus (L.) sakei e L. curvatus, Staphylococcus (S.) xylosus e S. saprophyticus, Enterococcus (E.) faecium e E. faecalis. Debaryomyces hansenii e Candida zeylanoides sono stati identificati nell’ambito della popolazione dei lieviti. La strategia scelta ha favorito il riconoscimento delle principali specie microbiche ricorrenti al termine della maturazione delle soppressate che possono eventualmente essere isolate e selezionate come colture starter autoctone. Pertanto, il secondo scopo è stato quello di caratterizzare e selezione i diversi ceppi di Staphylococcus xylosus e Lactobacillus spp. isolati, sulla base delle più importanti caratteristiche tecnologiche, al fine di valutarne le performances tecnologiche come colture starter nella produzione delle soppressate del Vallo di Diano. Le attività tecnologiche degli isolati (attività proteolitica a carico delle proteine sarcoplasmatiche e miofibrillari, lipolitica e nitrato reduttasica) sono state valutate in presenza della microflora endogena, inoculando i singoli ceppi in studio direttamente in un impasto carneo per soppressata che veniva successivamente insaccato e stagionato per 15 giorni. I risultati ottenuti hanno evidenziato non solo, la capacità di alcuni ceppi di prendere il sopravvento sulla microflora autoctona ma soprattutto di esibire interessanti caratteristiche tecnologiche tali da renderli elegibili per la formulazione di colture starter autoctone
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