Physicochemical Characterization and Nutrient Composition Decide Harvest Maturity of Cucumis melo Varieties

Cucumis melo is a polymorphic taxon belonging to the family Cucurbitaceae, with several varieties based on ovary pubescence. Cucumis melo var. momordica and Cucumis melo var. acidulus are popularized and highly cultivated forms in South India. The characteristic of   C.melo var.momordica is its fruit-cracking nature, which distinguishes the variety from others when it is ready to harvest.  So, it would be a herculean task for the farmers to harvest ripened fruits before it gets cracked. Analysis of the ripening process's physicochemical attributes and nutritional composition is inevitable to understand and establish proper harvest management for the varieties. The current study was conducted in the experimental field of the Department of Botany, University of Kerala using two different melon varieties, Cucumis melo var. momordica (Roxb.) Duthie & Fuller (Snap melon) and Cucumis melo var. acidulus L. Naudin (culinary melon), from January to October 2021. Fruits were harvested at five developmental stages (S1: 5 days after pollination (DAP), S2: 10 DAP, S3:15 DAP, S4: 20 DAP, S5: 25 DAP) and analysed for physical and biochemical characters. Results were analyzed statistically by using one way ANOVA (P≤0.05). Pomological characteristics such as fruit weight and length at different developmental stages showed a tremendous peak from S3 to S5 in both varieties. However, the firmness of the fruits decreased from the S4 to S5 stage in varieties, reducing sugar accumulated sharply from the S2 to S3 stage. Titratable acidity content in Cucumis melo fruits continuously increased from the S1 to S5 stage. On the other hand, the total carbohydrate, cellulose, protein, and amino acid content increased from S1 to S2 but decreased sharply in S3 and S5. Ascorbic acid, total phenolics, lipid peroxidation, and electrolyte leakage levels declined with fruit ripening in Cucumis melo varieties. As a result of all the quality parameters mentioned above, Cucumis melo fruit harvested at the S4 maturity stage was the ideal harvest maturity for long-distance transportation and had higher consumer acceptability before fruit cracking. Our findings showed that the physical-biochemical properties and nutritional composition of Cucumis melo varieties change dynamically during ripening. The study highlighted the significance of maturity stages for fruit quality and provided critical information for optimal harvest management of the fruits of Cucumis melo varieties.