Integrated preservative and packaging strategies suppresses senescence in loose marigold (Tagetes erecta L.) by preserving antioxidants and membrane integrity

Loose marigold flowers are highly perishable and suffer substantial postharvest losses because of rapid moisture loss, accelerated respiration, membrane deterioration, and oxidative damage. Although packaging technologies have been widely investigated for extending the shelf life of loose flowers, information on the integrated use of chemical preservatives and packaging materials remains limited. This study evaluated the combined effects of five preservative treatments [tap water (control), distilled water, boric acid (4%), salicylic acid (50 ppm), and ascorbic acid (50 ppm)] in combination with two packaging conditions (open/no packaging and muslin cloth bag) under ambient (30 ± 2 °C and 40–45% RH) and cold storage (5 ± 1 °C and 75–80% RH) conditions on postharvest quality of loose flowers. Cold storage extended flower longevity by 100–300% compared with ambient conditions, while muslin cloth bag packaging increased shelf life by 25–100% over unpackaged flowers. Among the treatments, 4% boric acid combined with muslin cloth bag packaging was the most effective, extending shelf-life from 4.0 to 7.0 days under low temperature and from 1.0 to 3.5 days under ambient storage. This treatment substantially reduced weight loss, resulting in approximately three-fold and four-fold lower PLW than the untreated unpackaged control under ambient and cold storage, respectively. It also maintained membrane stability, suppressed respiration, and preserved carotenoid content. In addition, it enhanced superoxide dismutase, catalase, and peroxidase activities, indicating improved antioxidant defence and reduced oxidative damage. These findings demonstrate that integrating boric acid with muslin cloth bag packaging delays postharvest senescence, extending shelf life up to 7.0 days and 3.5 days under cold and ambient conditions respectively, by maintaining membrane integrity and antioxidant defence, offering a practical strategy for reducing postharvest losses and extending the marketability of loose marigold flowers.