Variability in the Activity of Selected Hydrolytic and Antioxidant Enzymes in Four Maize Varieties (Zea mays L.) as a Function of Harvest Time in Daloa, Côte d’Ivoire

Maize grain maturation involves changes in hydrolytic and antioxidant enzyme activities that may influence physiological and biochemical characteristics at harvest. This study evaluated the effect of harvest time on selected enzymatic activities in four maize varieties, F1Vn10, KABAMANOJ, LG336 and EV8728, grown in Daloa, Côte d’Ivoire. Grain samples were collected at three harvest periods in accordance with the reproductive cycle of each variety. Lipase, α-amylase, protease, catalase and ascorbate peroxidase activities were determined using spectrophotometric assays. Enzyme activities varied according to both maize variety and harvest period. Lipase, α-amylase and protease generally showed greater activities during the earlier harvest periods and declined as harvesting was delayed. In contrast, antioxidant enzyme activities tended to increase at later harvests, with catalase and ascorbate peroxidase exhibiting comparatively high activities during advanced grain maturation. Differences among varieties were also observed, indicating varietal variation in enzymatic responses during grain development. These findings demonstrate that the biochemical characteristics of maize kernels change with harvest time and that hydrolytic and antioxidant enzymes follow different activity patterns during maturation. Harvest timing should therefore be considered when evaluating the physiological and biochemical status of maize grain. Further interpretation of these enzymatic patterns should take into account varietal characteristics and the maturation stage at which grain is collected.