Québec produces more strawberries than any other Canadian province. Strawberries are delicate and difficult to keep fresh. In response to this challenge, Monique Lacroix, professor at the Institut national de la recherche scientifique (INRS), and her team have developed a packaging film that keeps strawberries fresh for up to 12 days. The team’s results on protecting this film from mold and certain pathogenic bacteria have been published in Food Hydrocolloids.
The innovative film consists of chitosan, a natural molecule found in mussel shells. This food industry by-product contains important antifungal properties that help curb mold growth. The packaging film also contains essential oils and nanoparticles, both of which have antimicrobial properties.
“Vapors from essential oils protect strawberries. And when the film comes into contact with strawberries, the chitosan and the nanoparticles prevent mold and pathogens from reaching the surface of the fruit, ”says Professor Lacroix, an expert in food science.
The packaging could, among other things, be placed in blotting paper that the industry currently uses for strawberries.
Versatile protection
The formulation developed for this packaging film has the additional advantage that it is effective against several types of pathogens. The team tested the film on four microbial cultures. “Our work has shown the film’s effectiveness against Aspergillus niger, a highly resistant mold that causes significant losses in strawberry production,” said Lacroix.
This type of bioactive packaging also showed antimicrobial effectiveness against the pathogens Escherichia coli, Listeria monocytogenes and Salmonella Typhimurium, which are caused by contamination when handling food and are a major problem for the food industry.
Advantages of irradiation
Professor Lacroix and her team also combined the packaging film with an irradiation process. When packaging film was exposed to radiation, team members found a longer shelf life, which halved the loss compared to the control (without film or radiation). On day 12, the team recorded a loss rate of 55% for the control group of strawberries, 38% for the group with the foil, and 25% for additional radiation.
The irradiation not only extended the shelf life, but also helped to maintain or increase the amount of polyphenols in the strawberries. These molecules give strawberries their color and have antioxidant properties.
Source of the story:
Materials provided by National Institute for Scientific Research – INRS. Originally written by Audrey-Maude Vézina. Note: The content can be edited in terms of style and length.
