1,720,971 research outputs found
Active packaging based on coupled nylon/pe pouches filled with active nano-hybrid: Effect on the shelf life of fresh milk
No full textThe study reports on the preparation and characterization of an active packaging based on pouches composed of a coupled system nylon/polyethylene (PE). The PE layer was filled with and active nano-hybrid of layered double hydroxide (LDH) on which it was anchored salicylate, as antimicrobial molecule. The release of the salicylate anchored to the LDH was compared to the release of the molecule free dispersed into the PE and resulted much slower. It was evaluated the efficiency of the active packaging to inhibit Pseudomonas aeruginosa, Escherichia coli, Listeria monocytogenes, Salmonella typhimurium, and Campylobacter. Global migration tests on the PE active layer, using ethanol (50% v/v) as food simulant, demonstrated the possibility of such active nanocomposite to be used for food contact being the migration limits in compliance with those imposed from the EU regulation. Fresh milk was packed into the active pouches and pouches with unfilled PE layer, as control. The pH reduction as function of the time, due to the production of lactic acid, resulted much slower in the active packaging. Total bacterial count (TBC) was evaluated on the milk, either packed into the active packaging or the control, up to 50 days of storage at 4 °C. Shelf life of the milk was evaluated using the Gompertz model. It was demonstrated an increasing of the shelf life of milk packaged in active pouches from 6 days up to 10 days
A salicylate-functionalized PET packaging to counteract blue discoloration on mozzarella cheese under cold storage
No full textIn this work we tested a new technological solution to extend the shelf-life of Mozzarella cheese using a salicylate-functionalized PET packaging. To this aim, we inoculated ready-to-sell Mozzarella cheeses with Pseudomonas lactis ITEM 17298 strain, responsible for blue discoloration; mozzarella cheeses packed in treated or untreated trays were stored at 4 °C and monitored up to blue discoloration occurred. Results from microbiological analyses showed inhibitory effect against the pigmenting strain up to 8 days of cold storage in Mozzarella cheese packed in treated trays compared to the control samples. Likewise, CIELab values of b* and hue did not differ from those found on the uninoculated Mozzarella cheeses, delaying the appearance of bluish spots by approximately 2 days. Furthermore, the use of treated trays unpaired the formation of the biofilm by significantly reducing the amount deposited inside the treated trays compared to the control ones. For the first time, therefore, the use of an antimicrobial packaging with high technology readiness level has delayed the blue mozzarella occurrence specially contaminated samples. Further trials will have to be undertaken to optimize the salicylate concentration released in the tray in order to abate the risk of this fresh dairy product withdrawal from the market
Article a food-grade resin with ldh–salicylate to extend mozzarella cheese shelf life
No full textMozzarella cheese can be considered by far the world’s most popular Italian dairy product. Extending the shelf life of mozzarella cheese is an important issue in the dairy industry due to the high risk of contamination by several bacteria species, including spoilage pseudomonads. In this work, active packaging was prepared by coating traditional polyethylene terephthalate (PET) containers of “ovoline” mozzarella cheese with a food-grade resin mixed with a layered double hydroxide (LDH) in which salicylate anion was intercalatedby ionic exchange.. This antimicrobial molecule is listed in EC-Directive 10/2011/EC of 14 January 2011. Morphological arrangement of the molecule into the LDH layers was evaluated by X-ray diffraction (XRD) and controlled release followed by UV spectroscopy. Then, active trays were used to pack the mozzarella cheeses stored for 20 days at 4◦ C and under thermal abuse (15◦ C). Samples from both conditions showed coliform reduction (by ca. 2 log CFU/g) throughout the storage period. Depending on temperature, total mesophilic aerobic bacteria, Pseudomonas spp., yeasts, and mold loads were reduced in the first 3 days; at 4◦ C. Slower acidification and lower proteolysis were also found in treated samples in comparison to control ones. The fitting of the Gompertz function to coliforms and spoilage pseudomonads highlighted an increase in the shelf life of mozzarella cheese of ca. 2 days at 4◦ C. These results suggest that salicylate–LDH-coated PET may be applied to extend the shelf-life of mozzarella cheese and also counteract its spoilage if accidental interruptions to refrigeration occur
The Effect Of Additives And Complexing Agents On The Synthesis And Thermo-Oxidation Stability Of Poly(Butylene Terephthalate)
No full textPhysical and barrier properties of chemically modified pectin with polycaprolactone through an environmentally friendly process
No full textThe paper reports the preparation of a novel material composed of pectin chemically modified with polycaprolactone (PCL). PCL was firstly functionalized through radical grafting of maleic anhydride and glycidyl methacrylate in the molten state and then used as grafting agent onto pectins from apple, using a solvent free process. The obtained material was submitted to melt process on laboratory scale and films obtained. Structural, thermal, mechanical, and barrier properties to water vapor were evaluated and compared with pure pectin and modified PCL’s films. The used strategy allowed to overcome the processability problems of a natural polymer, like pectin, that undergoes degradation with the temperature and is not processable without additives and plasticizers. The proposed green process represents a good opportunity to manufacture waste materials from fruits to obtain flexible and fully biodegradable polymers for food packaging applications, as interesting alternative to not biodegradable traditional thermoplastics. [Figure not available: see fulltext.
Formulation of a bio-packaging based on pure cellulose coupled with cellulose acetate treated with active coating: Evaluation of shelf life of pasta ready to eat
No full textAn active packaging based on pure cellulose coupled with cellulose acetate coated with layered double hydroxide (LDH), hosting 4-hydroxybenzoate (listed in EC-Directive 10/2011) as an antimicrobial agent, was formulated and realized. The release of 4-hydroxybenzoate ionically bonded to the LDH layers was much slower than the molecule freely dispersed into the coating. The capability of the active packaging to inhibit Pseudomonas, Escherichia coli, Salmonella and Lactic Bacteria was evaluated, as well as the global migration with three different food simulant (i.e., acetic acid at 3% (v/v), ethanol at 50% (v/v) and vegetable oil) that demonstrated, in compliance with the migration limits of the EU regulation, the suitability of the prepared packaging to be employed as food contact material. Ready to east cooked tomato pasta was packaged into the active trays and in uncoated, as control, up to 30 days at 4 °C. Organoleptic characteristics, mold evolution, total mesophilic aerobic counts (TBC), Enterobacteriaceae, Lactic Bacteria and Pseudomonas, and in colony forming unit per gram (CFU/g), showed a significant activity of 4-hydroxybenzoate in increasing the shelf life of the pasta ready to eat
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Antimicrobial sorbate anchored to layered double hydroxide (LDH) nano-carrier employed as active coating on Polypropylene (PP) packaging: Application to bread stored at ambient temperature
No full textIn this paper it is reported the preparation of a food packaging based on isotactic polypropylene (PP) coated with layered double hydroxide (LDH) hosting sorbate as active molecule. The active nano-hybrid (LDH-sorbate) was dispersed into a food grade resin and used as coating. The release of the sorbate anchored to the LDH was compared to the release of the molecule free dispersed into the food grade resin and resulted much slower. It was evaluated the efficiency of the active packaging to inhibit Salmonella enterica subsp. arizonae, Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Campylobacter jejuni, and the global migration using two food simulant (i.e. poly (2,6-diphenyl-p-phenylene oxide) and vegetable oil). Experimental data, in compliance with the migration limits of the European Union regulation, demonstrated the suitability of the prepared material for food contact. White bread was packed into the active PP film and untreated PP, as control. Organoleptic characteristics, moisture analysis, peroxide evolution and mold count showed that the bread packaged in the active film retained its starting characteristics up to 12 days of storage at ambient temperature
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