From Cheese Whey Permeate To An Anti-Listeria Food Packaging Device: Bacterial Cellulose Nanocrystals/Sakacin-A Conjugates (Nanosak)
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Data di Pubblicazione:
2019
Citazione:
From Cheese Whey Permeate To An Anti-Listeria Food Packaging Device: Bacterial Cellulose Nanocrystals/Sakacin-A Conjugates (Nanosak) / A. Barbiroli, D. Bussini, S. De Benedetti, V. De Vitis, S. Farris, R. Gavara, P. Hernandez Munoz, L. Higueras, C. Mapelli, P. Motta, A. Musatti, D. Romano, C. Rovera, M. Rollini. ((Intervento presentato al 9. convegno SLIM Shelf Life International Meeting : June, 17th - 20th tenutosi a Napoli nel 2019.
Abstract:
In the present project cheese whey permeate (CWP), the residual by-product obtained by extraction of whey proteins from cheese whey, was used as substrate for the growth of bacterial species that produce two appealing molecules: the anti-listerial bacteriocin sakacin-A and bacterial cellulose (BC). BC is then turned into nanocrystals (BCNCs) that are finally conjugated with sakacin-A to obtain an innovative antimicrobial device for food which could support Listeria monocytogenes growth.
Sakacin-A was produced by Lactobacillus sakei DSMZ 6333 in liquid cultures. The highest bacteriocin production (around 300 AU/mL) was achieved after 9 h at 26°C; a food-grade, salt-free enriched sakacin-A extract was obtained by using a gravity reverse phase chromatography. BC was produced by Komagataeibacter xylinus DSMZ 2325 by static fermentation of CWP in presence of 0.5 U/mL of β-galactosidase at 30°C; after 7 days, BC yield was around 7 g/L. BCNCs were then obtained by acid hydrolysis mediated by sulfuric acid, with the goal of removing the amorphous regions of BC and introduce a net negative charge by esterification on the hydroxyl group on C6.
BCNCs/sakacin-A conjugates were prepared by exploiting their opposite charge: enriched sakacin-A extract was mixed with BCNCs and, after incubation, conjugates collected by centrifugation have a specific activity of 100 AU/mg BCNCs. Among all peptides present in the enriched sample, sakacin-A appears to preferentially absorb onto BCNCs, thus allowing its further purification.
Sakacin-A as well its BCNCs conjugates were then included in a hydroxypropil-cellulose coating spread onto paper sheets at a concentration of 5 and 25 AU/cm2. The addition of the coating did not bring any significant change in the oxygen barrier properties of the cellulosic substrate. In a similar way, the static contact angle of both uncoated and coated substrate was of approximately 130°. However, the presence of BCNCs seemed to increase the swelling phenomenon of the coating.
Sakacin A was also included in whey, caseine and cellulose derived matrices to prepare films and coatings with diverse results. The kinetics of Sakacin-A released from active films to aqueous food was analyzed by immersion of samples in water (as simulant) and measuring the anti-Listeria activity of the simulant after increasing times of exposure.
In vitro and in vivo antimicrobial trials were carried out on real food products demonstrated their anti-listerial effectiveness, proving that the developed devices can contribute to increase shelf life, quality and safety of perishable foods.
Tipologia IRIS:
14 - Intervento a convegno non pubblicato
Keywords:
sakacin-A; bacterial cellulose; cellulose nanocrystals; active packaging; Listeria
Elenco autori:
A. Barbiroli, D. Bussini, S. De Benedetti, V. De Vitis, S. Farris, R. Gavara, P. Hernandez Munoz, L. Higueras, C. Mapelli, P. Motta, A. Musatti, D. Romano, C. Rovera, M. Rollini
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