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United States Department of Agriculture

Agricultural Research Service

Research Project: POSTHARVEST TREATMENT FOR TROPICAL COMMODITIES FOR QUARANTINE SECURITY, QUALITY MAINTAINANACE, AND VALUE ENHANCEMENT Title: Development of edible bioactive coating based on modified chitosan for increasing shelf life of strawberries

Authors
item Vu, K.D. -
item Hollingsworth, Robert
item Salmieri, S. -
item Takala, P.N. -
item Lacroix, M. -

Submitted to: Food Research International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 22, 2010
Publication Date: January 1, 2011
Citation: Vu, K., Hollingsworth, R.G., Leroux, E., Salmieri, S., Lacroix, M. 2011. Development of edible bioactive coating based on modified chitosan for increasing shelf life of strawberries. Food Research International. 198-203.

Interpretive Summary: For increasing the shelf life of strawberries during storage, coatings made of polysaccharides of chitosan were applied to the fruits. First, tests were carried out with essential oils to determine their ability to slow the growth of moulds and other microorganisms isolated from strawberries. Red thyme (RT) and oregano extract (OR) were found to be most effective in this regard, whereas limonene (LIM) and peppermint oil (PM) had lower antimicrobial properties. The ability of these essential oils to increase the shelf life of strawberries held at 4 °C was also tested. RT, PM and LIM were found to be more efficient preservative agents for strawberries over 14 days of storage. Finally, chitosan was modified by acylation with palmitoyl chloride to increase its hydrophobicity (water repellency), to ensure a controlled release and improve its stability and adhesion to the fruit product. LIM and PM were incorporated into the modified chitosan to create edible coatings and these were tested for their ability to extend the shelf life of fresh strawberries during storage. Formulations based on modified chitosan containing LIM and Tween®80 were shown to perform better than other formulations.

Technical Abstract: For increasing the shelf life of strawberries during storage, bioactive coatings were applied using modified polysaccharides of chitosan. First, antimicrobial tests were performed with selected essential oils to evaluate their antimicrobial capacities against moulds and total flora isolated from strawberries. Red thyme (RT) and oregano extract (OR) were found as strong bioactive agents against moulds and total flora isolated from strawberries, whereas limonene (LIM) and peppermint (PM) had lower antimicrobial properties. These essential oils were also used as bioactive compounds which were sprayed onto strawberries and evaluated for their potential to increase shelf life during storage at 4 °C. RT, PM and LIM were found to be more efficient preservative agents for strawberries during 14 days of storage. Finally, chitosan was functionalized by acylation with palmitoyl chloride to increase its hydrophobicity, to ensure a controlled release and improve its stability and adhesion to the fruit product. LIM and PM were incorporated into the modified chitosan to create bioactive edible coatings and these were tested for their ability to extend the shelf life of fresh strawberries during storage. Formulations based on modified chitosan containing LIM and Tween®80 were shown to perform better than other formulations.

Last Modified: 10/30/2014
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