BIOCHEMICAL APPROACHES TO SPROUT CONTROL: A COMPARATIVE STUDY ON SEED YAM

This study evaluated the effectiveness of selected organic sprout suppressants—gibberellic acid (GA₃), neem seed kernel extract, and peppermint oil—on the sprouting behavior and quality attributes of stored yam tubers (Dioscorea alata L., variety UM 680). Untreated tubers served as the control. Small-sized seed yams (≤ 0.5 kg) were stored under ambient conditions, and changes in physicochemical and functional properties were monitored over the storage period. Parameters assessed included temperature, relative humidity, sprout count, weight loss, dry matter, starch yield, bulk density, water absorption capacity, reducing sugars, and amylose content. Storage temperature ranged from 26.90 ± 0.00 to 27.86 ± 1.00 °C, while relative humidity ranged from 77.96 ± 0.10 to 85.85 ± 0.02%. Dormancy was maintained for up to eight weeks, with sprout suppression following the order GA₃< neem seed kernel extract < peppermint oil < control. Weight loss increased progressively with storage duration, but GA₃-treated tubers recorded the lowest mean weight loss (11.39%), significantly lower (p < 0.05) than other treatments. Dry matter content increased during storage, while starch yield (15.62–23.32%) declined significantly with prolonged storage. Bulk density (0.42–0.77 g/mL) and water absorption capacity were significantly influenced by treatment, indicating suitability of UM 680 flour for food formulation and weaning diets. Amylose and total reducing sugars were evaluated for GA₃-treated and control tubers; amylose content decreased with storage time (7.09–11.52%), while reducing sugars ranged from 1.03 to 1.31%. Overall, GA₃ treatment was the most effective in suppressing sprouting while preserving tuber quality attributes. Given its natural origin, non-toxic mode of action, and established safety profile, gibberellic acid represents a safe and effective strategy for sprout control in stored D. alata seed yams.