Evaluation of Shellac and Sucrose Ester Fruit Coating Formulations that Support Biological Control of Post-harvest Grapefruit Decay
Titel:
Evaluation of Shellac and Sucrose Ester Fruit Coating Formulations that Support Biological Control of Post-harvest Grapefruit Decay
Auteur:
McGuire, Raymond G. Dimitroglou, Dimitrios A.
Verschenen in:
Biocontrol science and technology
Paginering:
Jaargang 9 (1999) nr. 1 pagina's 53-65
Jaar:
1999-03-01
Inhoud:
Fruit coating formulations of bleached and unbleached shellac were developed that support survival of the yeast Candida oleophila . These and commercial formulations based upon sucrose esters were evaluated for their ability to promote surface colonization of citrus for the biological control of post-harvest decay. The type of shellac did not affect yeast survival in the liquid formulation; however, a pH 7.6 was essential for satisfactory recovery from the liquid over 24 h. The replacement of morpholine and aqueous ammonia, which aid dissolution of shellac, with equally efficacious sodium or potassium hydroxide improved yeast survival, as did replacing the surfactant oleic acid with polyoxyethylene (20) sorbitan monooleate ( polysorbate 80). When formulations were applied to grapefruit, those that initially facilitated higher numbers of yeasts on the fruit surface later developed epiphytic populations that were significantly greater during the most critical first 2 weeks after harvest. As a group, coating formulations that incorporated sucrose esters favored the development of yeast populations to a greater extent than those based upon shellac and, over 6 months, grapefruit with these coatings were slower to decay. However, shellac formulations incorporating sodium hydroxide significantly extended the storage life of grapefruit compared with similar formulations with morpholine.
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