Physicochemical changes of stored cowpea, Vigna unguiculata, treated with selected essential oils to control cowpea bruchid, Callosobruchus maculatus (F.)

Author: Gayan R. S. Rubasinghege ¹, Priyani Paranagama ¹ and Krishanthi Abeywickrama ^2*

Received 2 June 2006, accepted 13 September 2006.

Abstract

Cowpea (Vigna unguiculata) seeds were treated with essential oils of C. citratus,C. nardus, C. zeylanicum, M. minutum and a standard pesticide (pirimiphos methyl) as fumigant toxicants. At the end of the four month storage period, physical and chemical properties of cowpea from each storage system were analyzed. Variation of physicochemical properties among treated storage systems was insignificant with one exception; 20±5% of moisture was lost in samples treated with essential oils due to absorption of treated oil. Higher protein, fat and dietary fiber contents were reported from essential oil-treated samples compared to those treated with pirimiphos methyl. With lower toxicity to humans and other mammals and less or no significant variation in physicochemical properties, the selected essential oils can be used as fumigant toxicants against Callosobruchus maculatus (F.).