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Submitted to: Postharvest Biology and Technology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 5/19/1998 Publication Date: N/A Citation: N/A Interpretive Summary: Postharvest decays of fruits and vegetables result in the spoilage of approximately one third of all produce harvested in the U.S. The availability of synthetic fungicides to control these decays is becoming severely restricted due to consumer concerns that these chemicals may be harmful to their health. We are exploring the use of natural compounds to replace synthetic fungicides. Our research has led to investigations of the antifungal activity of neem seed oil, a byproduct in the production of a natural insecticide. A formulation of this oil called Trilogy was compared to clarified neem seed oil and two other natural coatings for maintaining firmness and reducing decay caused by three of the most important storage pathogens of apples. Our results show that Trilogy has advantages over clarified neem seed oil and other natural coatings because it is easily applied, helps to reduce postharvest decay and also helps to reduce fruit softening. The coating provides a practical alternative to synthetic fungicides for protecting fruit against postharvest pathogens, and can also reduce softening, where other methods such as the use of modified atmosphere storage may not be feasible. Technical Abstract: Trilogy (an emulsifiable formulation of neem (Azadirachta indica A. Juss.) seed oil), Nature Seal 4000 (an edible carbohydrate coating) and heavy mineral oil (paraffin oil) were compared to clarified neem seed oil containing no emulsifier, and calcium chloride-infiltration, for maintaining quality and reducing decay of 'Golden Delicious' apples (Malus domestica). Fruit coated with these materials at harvest, and again after 4 months storage at 0C had less gray mold rot and less bitter rot and were significantly firmer than nontreated control fruit. Their firmness was comparable to that of calcium chloride-infiltrated fruit. The coatings also significantly reduced weight loss of fruit. However, none of the treatments significantly reduced blue mold rot. In vitro fungal growth studies demonstrated that Neem seed oil formulations are not fungitoxic to these pathogens, but act as protectants when applied to the apple surface. |
