Efficiency of Triple Bagging System and Lippia multiflora Leaves for the Vitamin Quality Preservation of Cowpea Seeds (Vigna unguiculata L. Walp)

Aims: To assess the effectiveness of triple bagging systems with or without Lippia multiflora leaves on the vitamin-quality of cowpea seeds during storage.

Methodology: Cowpea seeds that have undergone any treatment were collected from producer in the southwest of Côte d’Ivoire. The fresh leaves of Lippia multiflora were collected and dried in sunlight for 7 days in center of Côte d’Ivoire. The storage bags used were obtained from the suppliers to Côte d’Ivoire in Abidjan. All this material was sent to the Laboratory of Biochemistry and Food Sciences, Felix Houphouet-Boigny University, Côte d’Ivoire to perform the experiment. Thus for the experiment realization, a central composite design (CCD) was used. The first factor of CCD consisted to six types of packaging, namely: one control with polypropylene bag (TST), one triple bagging batch (composed of 2 internal layers in independent high density polyethylene 80 mm thick and a woven bag polypropylene) without biopesticide (H0), and four batches (H1, H2, H3 and H4) containing respectively (0.7%; 2.5; 4.3%; and 5%) biopesticide. The second factor, storage time, it included six periods of observation (0; 1; 2; 4.5; 7 and 8 months). HPLC techniques were used for the separation and quantification of β-carotene, α-tocopherol (vitamin E) and the water-soluble vitamins (thiamine, riboflavin, niacin, pyridoxine and folic acid). The estimated daily intake of folic acid (vitamin B9) was also evaluated for Ivorian adult of 70 kg.

Results: The results of vitamin properties indicate a significant influence (P < 0.05) between the type of treatments and shelf life. Multivariate analysis results (PCA and AHC) indicate that the addition of at least 0.7% Lippia multiflora leaves in triple bagging systems makes preservation more efficient and preserves the vitamin quality of the cowpea seeds during 8 months. The contribution to meeting vitamin B9 requirements is palpable when cowpea seeds are stored for up to 8 months in the triple bagging systems associated with the biopesticide.

Conclusion: Cowpea seeds storage in triple bagging systems with Lippia multiflora leaves appears as a method of effective and inexpensive conservation to ensure the vitamin-quality of cowpea.