Synergistic Effect of Aloe Vera Gel and Plectranthus Amboinicus Extract Composite Coating on Tomato Postharvest Preservation

Abstract

Postharvest quality deterioration of tomatoes leads to substantial losses during storage, primarily due to rapid ripening, moisture loss, and physiological degradation. This study investigated the effectiveness of an Aloe vera gel (AVG)-based edible coating, incorporating Plectranthus amboinicus extract (PEE), in extending the shelf life of tomatoes stored at room temperature. Tomatoes were treated with no coating (T₀), AVG with glycerol (T₁), and AVG incorporated with PEE and glycerol (T₂), and evaluated over 15 days for physical appearance, weight loss, chromaticity, pH, total soluble solids (TSS), and antimicrobial activity. Coated tomatoes, particularly T₂, maintained firmness, exhibited reduced shrivelling, and showed delayed visual deterioration compared to uncoated samples. At the end of storage, T₂ had the lowest weight loss (15.71%), the highest lightness (L* = 42.35), the lowest redness (a* =3.75), the lowest TSS (4.4%), and the lowest pH (4.35), indicating delayed ripening. This study demonstrates a novel dual-botanical edible coating system (AVG/PEE) that extends tomato postharvest shelf life via physical barrier-mediated metabolic regulation rather than direct microbial inhibition.