Genotypic Variation and the Effects of Nitric Oxide and 1-Methylcyclopropene on Mitigating Blackspot Bruise Enzymatic Browning in Potatoes

Abstract

Blackspot bruise is a common defect caused by physical injury of potato tubers that triggers internal enzymatic browning, leading to significant postharvest losses. Reducing the development of internal discolouration has enormous benefits for the industry. The objective of this study was to evaluate the efficacy of nitric oxide (NO) and 1-methylcyclopropene (1-MCP) in controlling blackspot enzymatic browning in Clearwater Russet, Russet Burbank, and Russet Norkotah potato cultivars. Tubers from these three cultivars were treated with NO (98 mL L −1 ; 5 h) and 1-MCP (0.139 mL L −1 ; 24 h), in addition to the untreated control. After the application of these treatments, half of the tubers were stored at 7.2 °C and 95% relative humidity (RH) for 14 days. The remaining half of the tubers were injured to induce blackspot bruising and then held for 24 h at 23 °C and 65% RH to allow browning symptoms to develop. 1-MCP and NO treatments significantly reduced blackspot enzymatic browning score to 1.3 and 1.1, respectively, compared to the untreated control (1.8) on a scale from 1 (lightest) to 4 (darkest). Treated tubers maintained higher lightness (L*) value of bruise area after peeling 70.47 in 1-MCP and 69.35 in NO, compared to the control, 66.67. Biochemical profile does not show any significant changes with treatment. This study provides preliminary proof of approaches to minimise bruise-associated discolouration in potatoes, with the potential to reduce postharvest losses and enhance the marketable value of fresh potatoes, which needs further verification to see its further implications.

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