Current scientific research is focused on edible coatings that are efficient and safe techniques for controlling quality deterioration and extending shelf - life of food products.Scientists of the Volcani Center (Bet Dagan, Israel), partner in Quafety European Project (2011-2014) on safety and quality of fresh-cut vegetables, have implemented a Layer-by-Layer (LbL) electrostatic deposition of oppositely charged natural polysaccharides, a polyanion alginate and a polycation chitosan, for coating a model food. For the study, the scientists investigated fresh-cut melon.
The performance of the alginate - chitosan coating was compared with single - layer coatings and with non - coated control. Combining the good adhesion to melon matrix of the inner alginate layer with antimicrobial activity of the outer chitosan layer reduced the bacteria, yeast and fungal counts by 1 - 2 log.
The bilayer coating slowed down the tissue texture degradation, after 14 days of storage only LbL samples maintained an appreciable firmness. Furthermore, the LbL coating prevented the increase in headspace CO2, ethanol and acetaldehyde, and did not induce the signs of hypoxic stress and off - flavor development observed in other samples, especially in alginate - coated melons. At the same time, the LbL coating resulted in somewhat increased produce weight loss due to the reduced surface water vapor resistance.
The scientists conclude highlighting the readily implementation of the method because it is cheap, simple and can improve quality and safety of fresh-cut products.
Source: Poverenov E., Danino S., Horev B., Granit R., Vinokur Y., Rodov V., ‘Layer-by -Layer electrostatic deposition of edible coating on fresh-cut melon model: anticipated and unexpected effects of alginate-chitosan combination’, Food and Bioprocess Technology, May 2013. Further info: http://link.springer.com/