Conservation of Mineral Elements in Maize Grains by a Triple Bagging System and Biopesticide (Lippia multiflora Moldenke and Hyptis suaveolens Poit Leaves).

Maize (Zea mays) is a staple food in the traditional diet of rural populations in Côte d'Ivoire. It is a source of many minerals. However, inefficient and sometimes harmful storage methods hamper its large-scale production in Côte d'Ivoire. It is in this context that a triple bagging system associated or not with biopesticides of plant origin (Lippia multiflora and Hyptis suaveolens leaves) was proposed in this study to evaluate its efficacy on the conservation of mineral quality of grains over an 18-month period following a 3-factor central composite design (CCD). The first CCD factor consisted of 6 observation periods: 0; 1; 4.5; 9.5; 14.5 and 18 months. The second factor, the type of treatment, included 1 control lot with a polypropylene bag (TB0SP) and 9 experimental lots including 1 lot in triple bagging without biopesticides (TB0P) and the remaining 8 lots containing variable proportions and/or combinations of biopesticides (TB1 to TB8). And finally, the third factor was the combination of the two biopesticides with % Lippia multiflora as a reference. The results indicate that the shelf life, ratio and combination of biopesticides significantly (P < 0.05) influence the mineral quality of grain maize. Principal component analysis revealed that the addition of at least 1.01% biopesticides (leaves of Lippia multiflora and Hyptis suaveolens) in triple bagging systems improves preservation efficiency and preserves the mineral quality of the grain over a period of 15 months as opposed to triple bagging without biopesticides where the mineral elements are preserved during the first 10 months of storage. However, this preservation of mineral quality is more pronounced in these storage systems with combinations of biopesticides (of which the proportion is greater than or equal to 3.99%) or with 2.5 % of individual biopesticides. Keywords— Maize conservation, mineral quality, triple bagging, biopesticides, Côte d'Ivoire. _________________________________________________________________________________