Quality of Tropical Sweet Potatoes Exposed to Controlled-atmosphere Treatments for Postharvest Insect Control

Abstract

Sweet potatoes ( Ipomoea batatas L.) were exposed to low O 2 and high CO 2 for 1 week during curing or subsequent storage to evaluate the use of controlled atmospheres (CA) as insecticidal treatments for sweet potatoes infested with sweet potato weevil ( Cylas formicarius elegantulus ). Sweet potato roots tolerated 8% O 2 during curing, but, when exposed to 2% or 4% O 2 or to 60% CO 2 plus 21% or 8% O 2 , they were unsalable within 1 week after curing, mainly due to decay. Exposure of cured sweet potatoes to 2% or 4% O 2 plus 40% CO 2 or 4% O 2 plus 60% CO 2 for 1 week at 25C had little effect on postharvest quality. However, exposure to 2% O 2 plus 60% CO 2 resulted in increased decay, less sweet potato flavor, and more off-flavor. These results indicate that exposure of sweet potatoes to O 2 and CO 2 levels required for insect control is not feasible during curing, but that cured sweet potatoes are capable of tolerating CA treatments that have potential as quarantine procedures.