In the framework of the EU project QUAFETY – Comprehensive approach to Enhance Quality and Safety of Ready to Eat Fresh products, scientists coordinated by Dr Victor Rodov at Institute of Postharvest and Food Sciences, Agricultural Research Organization, The Volcani Center (Israel) have compared the performance of two different approaches, blending and layer-by-layer electrostatic deposition (LbL), to combine two biopolymers, gelatin and chitosan, in edible films or coatings. The performance of the blended and LbL composite films and single-component gelatin and chitosan films was compared in terms of mechanical, optical, and spectroscopic properties. Chitosan, gelatin, gelatin-chitosan (blended), and gelatin/chitosan (LbL) formulations were applied as edible coating on fresh-cut melons as a food model.
Influences of the coatings on physiological, textural, and microbiological parameters of fresh-cut melons were studied in comparison with non coated control.
Gelatin-chitosan is an unusual combination of two biopolymers that can be applied both as blenden and as LbL formulations.
The scientists found that films prepared by the LbL approach benefit better mechanical properties than the blended films.
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Moreover, films based on two components, especially LbL films, showed higher permeability than the single-component films.
Edible coatings based on two components formulations resulted more effective in microbial inhibition than single-component films.
The LbL formulation showed effective total microbial growth inhibition, while blended formulation showed a significant antifungal activity after 11 days of storage.
The LbL formulation resulted superior in preservation of fruit texture and reduced slightly fruit weight loss, while blended film did not improve these parameters. Both composite coatings did not obstruct gas exchange and did not cause accumulation of off-flavor volatiles.
Source: Poverenov E., Rutenberg R., Danino S., Horev B., Rodov V., "Gelatin-Chitosan Composite Films and Edible Coatings to Enhance the Quality of Food Products: Layer-by-Layer vs. Blended Formulations", May 2014, Food Bioprocess Technology, Vol. 7, pagg. 3319-3327.
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