6533b7d8fe1ef96bd126a473

RESEARCH PRODUCT

On the use of carrageenan matrices for the development of antiviral edible coatings of interest in berries

subject

description

Different film-forming dispersions (FFD) based on κ−, ι− and λ− carrageenans and green tea extract (GTE) have been developed as an innovative strategy to guarantee the food safety of blueberries and raspberries. First, the FFD were characterized (surface tension and viscosity) and the physicochemical properties (water vapour permeability-WVP-, water sorption, contact angle, mechanical properties) of the stand-alone films were evaluated. Then, the FFD were applied to refrigerated-stored raspberries and blueberries, and the antiviral activity against murine norovirus (MNV), a cultivable norovirus surrogate, and hepatitis A virus (HAV) of coated fruits was determined at refrigerated (10 °C) and ambient conditions (25 °C). The type of carrageenan used significantly affected the WVP and the mechanical properties of the stand-alone films, being k-carrageenan films more rigid and less permeable. The incorporation of GTE resulted in less ductile and deformable films and slightly more permeable than their counterparts prepared without the extract. All the coatings were effective in extending the shelf life of raspberries and blueberries under refrigeration, preserving their firmness to a greater extent and promoting better appearance. In general, FFD with similar viscosity (κ− and λ− carrageenans) showed higher antiviral activity as the gelling capacity of the carrageenan increased (κ− carrageenan) because of the formation of a more cohesive polymer matrix and the higher solid surface density (SSD) deposited onto the berry surfaces. Adding GTE enhanced the carrageenan antiviral activity at both refrigerated and ambient temperatures in blueberries and raspberries, being slightly more effective in the case of MNV.