Innovative packaging strategies to reduce losses of fresh food products
Disorders characterized by the development of necrotic areas, rot, or other damage on fresh fruits and vegetables are usually caused by microorganisms (bacteria and fungi) saprophytes but also often plant pathogens, that is coming from the production fields.
These aspects are the basis of a partnership between the Italian research teams at Dep. DICA University of Perugia (Terni) and at Dep. DAFNE University of Tuscia (Viterbo), which have developed innovative and environmentally friendly materials (films to be used in the food industry), by using biodegradable polymers reinforced with active natural additives with antimicrobial activity.
Among the various studies the two research groups have investigated the properties of ternary polymeric films based on poly(lactic acid) (PLA), containing cellulose nanocrystals (CNC) and lignin nanoparticles (LNP) at different contents.
In this sense, some results were recently published in international journals (European Polymer Journal (2016) 79 1-12. "Synergic effect of cellulose and lignin nanostructures PLA based systems for antibacterial food packaging", and International Journal of Biological Macromolecules (2016) , www.ncbi.nlm.nih.gov/pubmed/27126170, "Effect of cellulose and lignin on disintegration, antimicrobial and antioxidant properties of active PLA films", Authors: W Yang, E Fortunati, Dominici F, G Giovanale, A. Mazzaglia, GM Balestra, JM Kenny, D Puglia), gaining considerable interest for industrial developments.
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Specifically, they have been designed and highlighted the thermal, optical, mechanical and morphological properties, of PLA based nanocomposites reinforced with nanocellulose and nanolignin. The results of the optical characterization have confirmed a synergistic effect of the two nanostructures in terms of optical transparency and contemporary barrier to UV light. Furthermore, the combination of the two lignocellulosic nano-reinforcements, has been shown to be effective in terms of increasing the crystallinity of multifunctional nanocomposite systems that have shown also enhanced mechanical strength. The combination of lignin nanoparticles and cellulose nanocrystals in PLA polymer matrix have produced a remarkable antimicrobial activity, reducing the multiplication of different phytopathogenic bacteria in nature such as, Pseudomonas syringae pv. tomato (Pst), Xanthomonas axonopodis pv. vesicatoria (Xav) and Xanthomonas arboricola pv. pruni (Xap), causal agents of tomato bacterial spot and bacterial speck, and bacterial canker of stonefruits, respectively, able to cause considerable damages and economic losses during post-harvest and marketing phases for final productions (tomato, plums, apricots, peaches).
The results obtained for the proposed multifunctional PLA based films containing lignin nanoparticles and nanocellulose highlighted important opportunities to develop innovative and environmentally friendly packaging strategies, useful for the entire food industry, able to reduce damages and alteration of fresh food caused by bacteria and, to limit, as consequence, economic losses.
Different studies that take into account different biodegradable materials, numerous active principles or additives with antimicrobial and/or antioxidant activity, and different microorganisms involved in these alterations, in order to develop innovative "active packaging" systems, able to reduce, by means of "green" and sustainable strategies, the current economic losses in different food chains.
For more information:
Prof. Giorgio M. Balestra
Dipartimento di Scienze per l'Agricoltura e le Foreste (DAFNE)
Università degli Studi della Tuscia
Via S. Camillo de Lellis
01100 Viterbo - Italy
Email: balestra@unitus.it