Efficacy of 1‑methylcyclopropene and modified atmosphere packaging on the ripening behaviour of guava stored under low-temperature conditions
摘要
Guava is highly perishable, with a short shelf life limiting its storability and marketability. The present study aimed to extend its storage life by combining 1-methylcyclopropene (1-MCP) with polypropylene-based modified atmosphere packaging (MAP) under two low-temperature conditions (8 and 12 °C). Mature green guava fruits cv. Arka Mridula were treated with 1-methylcyclopropene (1-MCP; 500 ppb), packaged using polypropylene (PP) and Cryovac® PD-961 (PD) films with micro- and non-perforated configurations, and stored at 8 ± 1 °C and 12 ± 1 °C to evaluate their effects on postharvest ripening and quality retention. The treatments were evaluated under two commercially relevant storage temperatures (8 °C and 12 °C) to assess their effectiveness in extending guava shelf life. Compared to untreated control fruits guava fruits treated with 1-MCP (500 ppb) in combination with polypropylene non-perforated (PP-NP) packs effectively maintained superior quality at 12 °C (21 days) and 8 °C (28 days), preserving colour, firmness, acidity (0.45–0.57%), ascorbic acid (118.60–91.76 mg/100 g), total phenols (444.47–613.68 mg GAE/100 g), and total flavonoids (332.09–302.8 mg CAE/100 g). This treatment significantly reduced respiration rate, ethylene production, browning enzyme activity, and malondialdehyde content (5.35 nmol/g FW), extending shelf life up to 28 days at 8 °C and 21 days at 12 °C while maintaining consumer-acceptable quality. In contrast, untreated fruit showed rapid deterioration and poor sensory appeal. Gene expression analyses revealed that ACC synthase, ACC oxidase, and expansin genes were markedly downregulated after 21 days, confirming the molecular basis for delayed ripening. This study is the first to report the combined use of 1-MCP and PP-based MAP in guava, demonstrating a novel, synergistic approach to delay ripening, preserve antioxidant potential, and enhance overall fruit quality during cold storage.