Natural Postharvest Preservation of Tomatoes Using a Cashew Gum–Lemongrass Essential Oil Edible Coating under Ambient Storage

Abstract

Tomatoes are considered one of the most widely grown horticultural crops, but their short shelf life is due to their climacteric ripening cycle and their susceptibility to microbial rot and mechanical damage after harvest, resulting in significant losses. The development of natural and effective post-harvest treatments is therefore a major challenge in preserving their quality and reducing losses. This study evaluated the effectiveness of an edible coating based on cashew nut gum, alone or enriched with lemongrass essential oil, on the preservation of cherry tomatoes harvested at the r stage of ripeness.  The fruits were divided into seven batches: an uncoated control, batches treated with a GC10%, GC15%, and GC20% formulation, and batches treated with the same formulations enriched with essential oil (GC/EO). After application of the coatings, the tomatoes were stored at room temperature (24 ± 2 °C; 84 ± 2% RH) for 25 days. Physicochemical analyses were performed every five days to assess weight loss, firmness, pH, titratable acidity, and color. The results showed that the cashew gum-based treatments significantly slowed the deterioration of fruit quality compared to the control. The GC20/EO treatment maintained high firmness (15.80 N) and stable titratable acidity (0.42%) after 25 days of storage. The GC20% formulation limited pH variations (5.77), color degradation (ΔE = 19.82), and acidity reduction. In addition, the GC15% treatment significantly reduced weight loss, reaching the lowest value at the end of storage. These effects can be explained by the formation of a semi-permeable barrier limiting gas exchange and moisture loss, as well as by the antimicrobial and antioxidant activity of the essential oil. In conclusion, cashew gum-based coatings, particularly the GC15% and GC20/HE formulations, are promising post-harvest treatments for extending the shelf life of cherry tomatoes and maintaining their physicochemical properties during storage at room temperature.