Impact of Different Rootstocks on Antioxidant Properties and Volatile Profile of Honeydew Melons (Cucumis melo L.) during Postharvest Storage

Abstract

Two rootstock hybrids of sweet melons and watermelons (“Kickstart” and “Carnivor” Cucurbita moschata × Cucurbita maxima) grafted onto two watermelon cultivars (scions), “Honeygoal” and “Honeyval”, were examined in this study to determine whether functional compounds, antioxidant properties, and volatile compounds were retained after five days of cold storage at 5 °C and 85% RH following harvest. An interaction exists between cultivars, rootstocks, and storage for total phenolic content, ascorbic acid, chlorophyll content, antioxidant activities, and volatile compounds. Generally, all functional compounds and antioxidant properties decreased during storage; however, “Honeygoal/Carnivor” in cold storage for 7 days retained the total phenols, ascorbic acid, chlorophyl contents, DPPH (15.47 IC50 mg/mL), ABTS (1.06 IC50 mg/mL) scavenging activities, and antioxidant power (IC50 mg/mL) higher than ungrafted, “Honeyval” or “Honeygoal/Kickstart”, “Honeyval/Carnivor” or “Honeyval/Kickstart” melons. The heat map showed a higher abundance of volatile compounds in “Honeygoal/Carnivor” and “Honeyval/Carnivor” melons stored for 7 and 14 days while “Honeygoal/Kickstart” or “Honeyval/Kickstart” requires 14 days of storage. “Honeygoal/Carnivor” and “Honeyval/Carnivor” melons stored for up to 7 days in cold storage were preferred by panelists. Hence, grafting “Honeygoal” melons onto “Carnivor” rootstocks helped to improve the functional compounds, antioxidant properties, and volatiles during storage for 7 days after harvest.