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United States Department of Agriculture

Agricultural Research Service

Research Project: ENHANCEMENT OF THE QUALITY AND MICROBIAL STABILITY OF FRESH FRUITS AND VEGETABLES WITH EDIBLE COATINGS AND OTHER SURFACE TREATMENTS

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2007 Annual Report


1a.Objectives (from AD-416)
Improve technology that preserves quality, edibility and storability of whole fresh and fresh-cut produce, with emphasis on chemical-free and organic-compatible treatments. Model how fruit coatings influence concentrations of internal gases and, thus, affect quality.


1b.Approach (from AD-416)
Assess potential incidence of disease preharvest to anticipate problems under postharvest conditions. Test antagonistic microorganisms as a decay-control treatment as well as antimicrobial essential oils and natural phytoalexins. Coating formulations will be developed from new or traditional ingredients and analyzed for their ability to block pores in the fruit peel, and reduce microbial populations for intact and fresh-cut produce. Intact fruit will undergo treatments that reduce wound-ethylene in the fresh-cut product. In all cases, affect of treatments on quality will be evaluated.


4.Accomplishments
Antimicrobial coatings and surface treatments: Demonstrated that certain commercial coating ingredients and other antimicrobial aromatic compounds were lethal to the citrus pathogenic canker organism on citrus peel using a screening method developed in the laboratory. The method allows screening in vitro, followed by screening on fruit peel explants and finally on the whole fruit. Citrus fruit from Florida are not shipped to other citrus growing areas in the U.S. and abroad due to the possibility of harboring the citrus canker bacteria. Packers need a method of removing/destroying the bacteria on the fruit before leaving the packinghouse, in order to have this quarantine lifted. The research relates to NP 306 "Quality and Utilization of Agricultural Products", Component 1d, "Preservation and/or Enhancement of Quality and Marketability".

Quality and safety of enzyme-peeled oranges: Demonstrated that enzyme-peeled orange fruit segments were preferred by panelists due to appearance and softer texture compared to the water-infused method of peeling fruit, and that the enzyme infiltration did not result in more contamination than manually-peeled fruit. Infiltration with citric acid further reduced microbial counts in the peeled orange slices without affecting flavor. The fresh-cut industry has the perception that infusing citrus fruit with enzymes would result in microbial contamination, but this study showed this not to be the case. Peeled citrus segments would be a beneficial addition to a healthy diet, especially for school lunches since they are much more shelf stable than other fresh-cut fruit and easy for young children to consume. This research relates to NP 306 "Quality and Utilization of Agricultural Products", Component 1d, "Preservation and/or Enhancement of Quality and Marketability".

Coatings were developed in cooperation with the Instituto Valenciano dew Investigaciones Agrarias, Postharvest Department, Spain for tangerine-type citrus fruit that have a more natural shine and that develop less off-flavor that is so often associated with commercial citrus coatings. The coatings developed were tested on oranges and tangerines, and coated fruit were evaluated for appearance and flavor. These coatings may be compatible for the organic market. This research relates to NP 306 "Quality and Utilization of Agricultural Products", Component 1d, "Preservation and/or Enhancement of Quality and Marketability".


5.Significant Activities that Support Special Target Populations
Coatings and surface treatments were developed for lychee fruit that keep the red outer coating from turning brown and causing the fruit to become unmarketable. This research was done in collaboration with Chiang Mai University in Thailand, and benefits rural family-owned tropical fruit farms in south Florida.


6.Technology Transfer

Number of non-peer reviewed presentations and proceedings14
Number of newspaper articles and other presentations for non-science audiences1

Review Publications
Pinnavaia, S., Baldwin, E.A., Plotto, A., Narciso, J.A., Senesi, E. 2007. ENZYME-PEELING OF VALENCIA ORANGES FOR FRESH-CUT SLICES. Proceedings of Florida State Horticultural Society. 119:335-339.

Plotto, A., Narciso, J., Baldwin, E.A., Rattanapanone, N. 2006. Edible coatings and other surface treatments to maintain color of lychee fruit in storage. Proceedings of Florida State Horticultural Society. 119:323-331.

Narciso, J.A., Baldwin, E.A., Plotto, A., Ference, C.M. 2007. Preharvest peroxyacetic acid sprays slow decay and extend shelf-life of strawberries. HortScience. 42(3):617-621.

Narciso, J.A. 2005. An assessment of methods to clean citrus fruit surfaces. Proceedings of Florida State Horticultural Society. 118:437-440.

Last Modified: 9/10/2014
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