Cellulose Acetate Butyrate Nanocomposites with Antimicrobial Properties for Food Packaging

The cellulose acetate butyrate/modified motmorillonite (Cloisite20A and Cloisite30B) nanocomposites were prepared by two different solvent casting methods. All antimicrobial nanofillers were characterized using X‐Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and antimicrobial components (carvacrol and cinnamaldehyde) included in the nanofillers were determined by gas and HPLC chromatography. These analyses confirmed the inclusion of antimicrobial agents in organoclay. The nanocomposite films were characterized by XRD, TGA, Differential Scanning Calorimetry (DSC), Oxygen and Water Vapor Permeability, mechanical properties and antimicrobial behavior against E coli, L.innocua, S. cerevisiae. All films presented a reduction of at least 2.0 log cfu/mL when applied film nanocomposites procedure in which antimicrobial components are included in the last stage of the process and they are not previously included in the organoclay. Copyright © 2012 John Wiley & Sons, Ltd.     

Modeling the release of antimicrobial agents (thymol and carvacrol) from two different encapsulation materials

Food Science and Biotechnology - The release of microencapsulated natural antimicrobial (AM) agents (thymol and carvacrol) from two encapsulating matrixes [maltodextrin (MD) and soy protein (SP)]...     

Development of an Active Packaging Film Based on a Methylcellulose Coating Containing Murta (<Emphasis Type="Italic">Ugni molinae</Emphasis> Turcz) Leaf Extract

A new active packaging film based on murta leaf extract was elaborated. The extract was incorporated into a methylcellulose layer which was coated on a low-density polyethylene (LDPE) film. Its antioxidant effectivity, antimicrobial activity, and physicochemical properties were evaluated. The active film was able to keep its antimicrobial and antioxidant properties for at least 60 days. During this time, the growth of Listeria (L.) innocua was reduced by 2 log cycles and free radical formation could be inhibited by about 90 % for films stored under light and dark conditions. The active coating on the LDPE film did not affect the thermal and water vapor transmission properties; however, slight changes in the mechanical, color, and optical properties were observed. Finally, a sensory analysis showed that active coating did not change the flavor and odor properties of a fatty food packed inside the active material. This suggests that this active packaging film could be used to extend the shelf-life of packaged food.     

Comparison between thermal and microwave treatment on the overall migration of plastic materials intended to be in contact with foods

The results are presented of overall migration testing of a wide range of plastic packaging, intended to come into direct contact with foodstuffs, after microwave cooking. The values for overall migration obtained for all the plastic materials tested are significantly below the limit required by Directive 90/128/EEC. Among the materials tested, it can be pointed out that PVC is the material whose overall migration increases most significantly after microwave cooking, and it is also affected by aqueous simulants in contact with it. Acetic acid promotes migration for PVC after microwave cooking. The results have been compared with overall migration of same samples at normal conditions (40°C for 10 days), and after thermal treatment at 80°C and 121°C for 30 minutes. Copyright © 1999 John Wiley & Sons, Ltd.     

Experimental and theoretical study of LDPE: Evaluation of different food simulants and temperatures

The mass transfer process of additives from plastic packaging to food is of great importance and interest because of the possible harmful effects on the human health. In this work the effect of different food simulants (EtOH 10–50%) and temperatures (28–60 °C) on the specific migration of Octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (I-1076) from LDPE films is experimentally and theoretically studied, considering also the antioxidant stability in the food simulants studied at different temperatures.On the other hand, a phenomenological model based on a resistances-in-series which was resolved through the Regula Falsi algorithm according to a routine that considers the income of the structural parameters of the system and experimental conditions in which migration testing was performed. Diffusion coefficients of I-1076 in LDPE were ranged between 8.0E10–14 and 1.2E10–12 (m² s^{− 1}) for temperatures of 28 to 60 °C, respectively. The coupled effect of mass transfer and thermodynamical aspects was analyzed through the parameter Bi/K_P/FS proposed in this work, estimated in order to identify the combined contribution of the transport rate and the availability of the migrant compound in the food phase.     

The antimicrobial activity of microencapsulated thymol and carvacrol

The aim of the present study was to determine the antimicrobial (AM) properties of plastic flexible films with a coating of microcapsules containing carvacrol and thymol as natural AM agents. Microencapsulation of these agents enables their controlled release and leads to the destruction (or growth inhibition) of a broad spectrum of microorganisms such as, Escherichia coli O157:H7, Staphylococcus aureus, Listeria innocua, Saccharomyces cerevisiae and Aspergillus niger. It was found that the studied AM agents are strong inhibitors to the growth of mycelium, but they were not effective against spore germination of mold. Thymol (T) and carvacrol (C) showed a significant AM activity against the studied microorganisms, with minimal inhibitory concentrations (MIC) of 125-250 ppm and 75-375 ppm for thymol and carvacrol respectively. The synergistic effect of combinations of thymol and carvacrol was also studied and it was found that the highest synergism was achieved at a concentration of 50% T and 50% C. The release of the AM agents was carried out at 4 °C during 28 days. The concentration of the microencapsulated AM agents showed a range of zones of inhibition of 4.3-11.3 mm for the microorganisms at 10% of thymol and 10% of carvacrol. At these concentrations the release of the AM agents (within 48 h) was greater than required for the most resistant microorganism (E .coli O157:H7), as reflected by the relatively large zone of inhibition. The results of the present study confirm the suitability of using microencapsulated thymol and carvacrol incorporated in polymer films for AM food packaging.