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Active packaging


Oxygen scavenging. Effectiveness study of two oxygen absorber sachets based on iron powder.

The main objective of this experimental work was to evaluate the effectiveness of two different oxygen absorbing sachets based on iron powder in respect of their capacity in removing oxygen from a package’s head space in different conditions of temperature and oxygen partial pressure. Although the reliability of such active solutions is already stated by their diffusion in the market, an effectiveness investigation was carried out, focusing the attention on the absorption capacity, the absorption reaction’s kinetic and the oxygen absorption rate in different conditions of temperature and oxygen partial pressure. The absorption phenomenon was largely dependent on the temperature and in all the conditions tested, for both the devices a complete absorption of oxygen was reached in less than 24 hours, indicating a very good performance of the absorbing sachets in modifying the inner atmosphere of the packages.

Limbo, S. Posata, A., Piergiovanni, L. 2001. Oxygen scavenging. Effectiveness study of two oxygen absorber sachets based on iron powder. In: Ricerche e Innovazioni nell’industria alimentare. Vol. V. p.158. Porretta, S. (Ed.). Chiriotti Editori, Pinerolo, Italia.


The combined effects of carbon dioxide and ethanol vapours on the preservation of sliced bread stored at low oxygen partial pressure.

The experimental design proposed in this work aims at statistically estimating the simultaneous effects of carbon dioxide and ethanol vapours on storage of sliced bread. In our experiments, the bread is inoculated with a spore suspension of Aspergillus niger and pouched with different combinations of carbon dioxide and ethanol vapours released by an ethanol emitter. Results show that Aspergillus niger grows with high levels of carbon dioxide, even if oxygen was present at low concentration; moreover, the ethanol alone was not sufficient to inhibit mould growth. Microbial, sensory and textural protection requirement of sliced bread can be guaranteed when two or more preservative factors are involved.

Limbo, S., Mascheroni, E., Piergiovanni., L. 2007. The combined effects of carbon dioxide and ethanol vapours on the preservation of sliced bread stored at low oxygen partial pressure. Italian Food and Beverage Technology. XLIX (2007) October


Influence of temperature and sakacin A concentration on survival of Listeria innocua cultures.

The antimicrobial activity of sakacin A, a bacteriocin produced by Lactobacillus sakei, was investigated at 30, 10 and 4 °C against Listeria innocua in stationary and lag phases of growth. When sakacin was added to Listeria innocua cells in stationary phase, two death kinetics were observed. Populations of Listeria innocua were reduced up to three log cycles when sakacin A was increased from 0 (control) to 1600 AU ml-1. When sakacin A was added to Listeria innocua cells in lag phase, lag time, inhibition time and rate were proportionally extended, and maximum population decreased when employing higher bacteriocin levels. Sakacin A was found to influence Listeria innocua growth, a microorganism able to grow at 4 °C. At refrigerated temperatures, the addition of sakacin A was found to inhibit Listeria innocua cell growth. Sakacin A may be considered a promising molecule to be used as antimicrobial agent to preserve the shelf life of refrigerated foods.


Trinetta, V., Rollini, M., Limbo, S., Manzoni, M. 2008. Influence of temperature and sakacin A concentration on survival of Listeria innocua cultures. Annals of Microb. 58:633-640


Diffusion kinetic of propolis compounds in Poly-lactic acid polymer for the development of active food packaging films

Promising active packaging systems are based on the incorporation of substances, in particular natural antimicrobial and antioxidant agents, in food biopackaging materials. Antimicrobials in active packaging systems could be distinguished in two types according to their volatility, i.e. (i) volatile compounds prevent anti-microbial growth by direct or indirect contact between the packaging and the food; whereas (ii) non volatile compounds require direct contact between the food and the packaging to be efficient.
An active release system for food packaging application was realized by incorporation of propolis into Polylactic acid (PLA) film. In order to achieve the release of propolis polyphenols, the composition of the films was modified by adding polyethylene glycol (PEG) and calcium bentonite (CB) to the initial PLA casting solution. The diffusion kinetics was measured in food simulating liquid. Experimental polyphenols release kinetics were analyzed using distinct Fickian models with specific assumptions. The analytical solution of Fick’s second law taking into account the selling out of the food simulating liquid proved to be more precise to identify the diffusivity value of polyphenols in PLA matrix.


Lysozyme immobilization on cellulose-based materials as a tool for food protection

Antimicrobial substances like proteins may be introduced into food packaging materials to control growth of pathogens and spoilage microorganisms, and to generally enhance product shelf-life. Some proteins, like invertase and lysozyme have already been classified as food additives by the European Directive 95/2/EC, and several strategies aiming at the integration of these bioactive compounds in conventional or renewable packaging materials have been developed in literature, showing good perspectives also for the controlled release of these antimicrobials.
In this project, innovative antimicrobial cellulose-based packaging materials are prepared by binding proteins like lysozyme and lactoferrin to paper modified with anionic polyelectrolytes; these modifications might enhance the paper binding capacity to positively charged proteins.
Results show that Paper charge density is increased by incorporating carboxy-methylcellulose and polygalacturonic acid, resulting in a significant increase of the amount of bound proteins. These studies also allowed to assess the nature of the interactions between the proteins and the various types of paper and the activity of proteins loaded papers.