Efficacy of Lippia multiflora (Verbenaceae) and Hyptis suaveolens (Lamiaceae) Leaves on Merchant Quality of Stored Maize Grain (Zea mays L.) in Côte d’ivoire

The aim of this study was to monitor the merchant quality of maize grains stored for 9 months in polypropylene bags containing leaves of Lippia multiflora and Hyptis suaveolens. It was carried out in villages of Timbé and Soko respectively in departments of Katiola (Hambol region, Center-North) and Bondoukou (Gontougo region, Northeast) of Côte d'Ivoire. The parameters determined were weight loss, damages, moisture, fat, acidity and peroxide values. The mass losses and damages were determined by methods of Harris, Lindblad and Boxall respectively, while moisture, fat, values of acidity and peroxide were measured according to AOAC's standard methods. The batches treated with the leaves of L. multiflora and H. suaveolens recorded the best values compared to control batches irrespective of the type of leaf, the study site and the parameter studied. Indeed, the moisture levels of grains varied between 9.00% and 14% for control batches and were less than 13% for the treated batches. Concerning mass losses, the treated batches had rates of less than 15.25% while those of the control batches reached 24.25%. Grain damage was up to 47.40% in the control batches but remained below 32.40% in the treated batches. For the fat content of the grains, the averages decreased from 5.4% to 1.90% for control batches and remained above 2.4% for treated batches. The opposite phenomenon was observed in acidity and peroxide values which were higher in control batches than in treated batches. These results indicate that treatment of maize grains with leaves of L. multiflora and H. suaveolens makes it possible to inhibit activity of insects and to preserve quality of grains with a remanence of up to 9 months. This inexpensive and easy-to-use treatment should be popularized among farmers.