Effects of edible coating (guar and tara gam) applications on post-harvest fruit quality and gene expressions in cherry tomatoes

Abstract

Post-harvest storage life of tomatoes (Solanum lycopersicum L.) is relatively short, posing a significant challenge in maintaining fruit quality. Addressing this challenge, our study aimed to evaluate the effects of 1.5 % guar gum and tara gum applications on post-harvest fruit quality and gene expression in Bamano and Yolita cherry tomato varieties cultivated under greenhouse conditions. The tomatoes were stored at 10ºC with 80 ± 5 % relative humidity, and the study assessed changes in respiration rate, external ethylene production, in-package gas composition (O₂ and CO₂), organic acid content (citric acid, malic acid, succinic acid, tartaric acid, fumaric acid, and oxalic acid), and the expression of genes associated with respiration (LeAOX1a) and ethylene biosynthesis (LeACO1 and LeACS2). The findings revealed that 1.5 % guar and tara gum edible coatings effectively suppressed respiration rates and external ethylene production in both cherry tomato varieties. Additionally, these coatings regulated in-package gas compositions (O₂ and CO₂) and significantly contributed to the preservation of organic acids. Gene expression analysis indicated that in the Bamano variety, the expression levels of LeAOX1a and LeACS2 increased until the 24th day of storage, while LeACO1 expression levels rise until the 30th day. For the Yolita variety, the expression levels of respiration- and ethylene-related genes (LeAOX1a, LeACS2, and LeACO1) increased until the 24th day. In conclusion, the study demonstrated that 1.5 % guar gum edible coating effectively extended the post-harvest storage life of Bamano cherry tomatoes to 30 days and Yolita cherry tomatoes to 24 days, based on the evaluated parameters. These findings highlight the potential of guar gum coatings as a promising approach for improving the post-harvest quality and storage life of climacteric tomatoes.