Cassava Starch and Tea Extract Edible Coating Delays Postharvest Quality Loss of Tomato Fruit Under Ambient Storage in Rwanda

Abstract Background Tomato ( Solanum lycopersicum L.) is highly perishable, and postharvest losses threaten food security and smallholder income in Rwanda, where refrigeration and plastic packaging are largely inaccessible. This study evaluated a low-cost cassava starch–glycerol coating containing aqueous tea extract for preserving tomato under ambient storage. Methods Coatings contained 3–5% (w/v) gelatinised cassava starch, 1–2% (v/v) glycerol and 0.5% (T1) or 1.0% (T2) (w/v) dried tea extract. Uncoated (T0) and dip-coated tomatoes (three replicate lots per treatment) were stored at 25 ± 2°C and 65–85% relative humidity for 21 days. Weight loss, moisture content, vitamin C, titratable acidity, crude fibre, total soluble solids, visual deterioration and sensory attributes were assessed on days 1, 7, 14 and 21 and analysed by two-way ANOVA or non-parametric tests. Results Both coatings reduced weight loss at every sampling day (p < 0.001); on day 21, weight loss was 15.94% in T0, 10.72% in T1 and 7.26% in T2. T2 fruit also retained more vitamin C (12.0 vs 6.47 mg/100 g), titratable acidity (0.43 vs 0.36%) and crude fibre (1.23 vs 1.00%) than T0, and less visual deterioration (2.5 vs 4.0). Uncoated fruit became sensorially unacceptable after about 15 days, whereas both coated treatments remained acceptable at day 21. Conclusions The coating delayed tomato quality loss without refrigeration, with the 1.0% tea-extract formulation performing best. Because no starch-only coating was tested, the specific role of the tea extract remains to be confirmed. Made from locally available, biodegradable materials, the coating is a promising postharvest option for smallholder farmers and traders.