Optimization of Maize-Tacca Starch Composite Edible Coating Using Response Surface Methodology for Prolonging Shelf Life of Tomato

Abstract

Edible coatings play an important role in increasing the shelf life of fresh produce and have the potential to minimize postharvest losses. The present study evaluates the effect of composite edible coatings containing maize and tacca starch, black seed, and glycerol on the physicochemical attributes and microbial growth of tomatoes stored at an average temperature of 25.34 °C and relative humidity of 90.95%, respectively. Response surface methodology (RSM) based on D-optimal design was employed for the coating formulation with twenty (20) randomized experimental runs. The formulation design was constrained as follows: maize starch (20-40%), tacca starch (50-70%), black seed (5-10%) and glycerol (2-10%). The top three optimized coatings with the best desirability were then applied to tomato samples and stored with the control for a duration of 24 days. The result of the study shows that all coated samples exhibited lower degradation in weight loss, total soluble solids, titratable acidity, pH, and lycopene content in contrast to uncoated samples. Optimization analysis on the data obtained showed that a blend of 23.945% maize starch, 65.685% tacca starch, 2% glycerol, and 8.370% black seed recorded the least microbial count at the end of the storage period. The composite edible coating is promising for extending the shelf life of tomatoes.