Fac-simile Scheda Linee di Ricerca - Federalimentare

medium was assessed on Pseudomonas spp by comparing results obtained from direct addiction of thymol tothat obtained from released thymol. Results show that differences are negligible.2. Conte A., Buonocore G.G., Sinigaglia M., Lopez L.C., Favia P. , d’Agostino R., Del NobileM.A. 2008. Antimicrobial Activity of Immobilized Lysozyme on Plasma Treated PolyethyleneFilms. Journal of Food Protection. 71(1), 119-125.In this paper we tested the antimicrobial activity of polyethylene films modified by means of plasma processesfollowed by the chemical immobilization of lysozyme, an antimicrobial enzyme. In order to chemically immobilizethe enzyme in its active form at the surface of polyethylene, substrates plasma-treated in different experimentalconditions were soaked in lysozyme solutions at different concentrations. The immobilization of the enzymewas checked and the antimicrobial activity of the films was investigated by observing the death rate of Micrococcuslysodeikticus cells suspended in phosphate buffer in contact with the films. The results clearly indicatethat plasma-treated films loaded with lysozyme are active against the selected microorganism. A modified versionof the Gompertz equation was used to quantitatively valuate the dependence of the antimicrobial activity ofthe films, on both plasma treatment conditions and lysozyme concentrations.3. Conte A., Buonocore G.G., Sinigaglia M., Del Nobile M.A. 2007. Development of ImmobilizedLysozyme based Active Film. Journal of Food Engineering. 78, 741-745.The aim of this work is to develop an active packaging material in which the active compound, lysozyme, iscompletely immobilized onto the polymeric material and acts directly from the film without being released intothe packed foodstuff. Crosslinked films of polyvinyl alcohol, differing in the amount of both antimicrobial andbinding agents, were prepared. In order to determine the amount of active substance completely bonded to thepolymer backbone, lysozyme release tests were run. The antimicrobial activity of the developed active films wasinvestigated in order to verify their effectiveness in controlling microbial spoilage. A modified version of Gompertzequation was used to quantitatively determine the antimicrobial activity of the films. Results indicate thedeveloped active films are effective in inhibiting the growth of selected microorganism, and that the antimicrobialactivity of the investigated films increases as the amount of enzyme incorporated increases.4. Conte A., Sinigaglia M., Del Nobile M.A. 2006. Antimicrobial Effectiveness of LysozymeImmobilized on Polyvinylalcohol-Based Film against Alicyclobacillus acidoterrestris.Journal of Food Protection. 69(4), 861-866.In this work the effectiveness of active polyvinylalcohol (PVOH) based film against Alicyclobacillus acidoterrestriswas assessed. The developed active film was obtained by immobilizing an active compound on the surfaceof the polymeric matrix and by putting the obtained film in contact with a medium inoculated with microbialcells. Microbiological tests were conducted with success both on a single strain and on culture cocktail of A. acidoterrestrisat 44°C. By monitoring the viable cell concentration at three different packaging conditions it waspossible to demonstrate that the active film, with a comparable efficacy for both single strain and culture cocktail,maintained its efficacy at different medium volumes. The same microbial tests were conducted also on viablespores of the investigated microorganism, inoculated both in laboratory medium and in apple juice. The resultsindicate that the developed active film successfully inhibits, more easily than cells, the viable spores in bothinvestigated media.5. Conte A., Buonocore G.G., Bevilacqua A., Sinigaglia M., Del Nobile M.A. 2006. Immobilizationof lysozyme on Polyvinylalcohol Films for Active Packaging Applications. Journal ofFood Protection. 69(4), 866-870.A new technique for the immobilization of lysozyme onto the surface of polyvinylalcohol films is presented. Theactive compound was sprayed along with a suitable bonding agent onto the surface of the crosslinked polymericmatrix. Active compound release tests determined the amount of lysozyme immobilized on the film surface. Byusing Micrococcus lysodeikticus the antimicrobial activity of the films was determined and the results correlatedwith the amount of immobilized lysozyme. This new technique was effective for immobilizing the enzyme andthe developed films were active against the test microorganism. Results were compared with those obtained witha different immobilizing technique, in which the active compound was bound into the bulk of the polymeric film.As expected, the surface immobilized lysozyme films have a higher antimicrobial activity than bulk bound films.SISTAL - SOCIETA’ ITALIANA DI SCIENZE E TECNOLOGIE ALIMENTARIDipartimento di Scienze e Tecnologie Agroalimentari, Università degli Studi della TusciaVia San Camillo de Lellis, 01100 ViterboTel.: 0761- 35 74 94/7 , Fax: 0761- 35 74 98, e-mail: mmoresi@unitus.it119